bg_xaydungcachethongnhung.pdf

7/25/2019 BG_Xaydungcachethongnhung.pdf

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Xy dng cc H thng nhng

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HC VIN CNG NGHBU CHNH VIN THNG

Khoa Cng nghthng Tin

Bmn Khoa hc my Tnh

XY DNG CC

HTHNG NHNG

H Ni, thng 11 nm 2013

(bn sa v bsung)

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Li ni u

Dy v hc h thng nhng l cp ti mt ch c phm vi rng bao gm thit k,mi trng ng dng, loi hnh cng ngh, qui tc cn thit tip cn mt cch c h thng.

Lnh vc thit k v ng dng cc h thng nhng bao gm : cc h thng vi iu khin (micro -controller) nh v n gin, cc h thng iu khin, h thng nhng phn tn, h thng trnchip, mng my tnh (c dy v khng dy), cc h thng PC nhng, cc h thng rng buc thigian, robotic, cc thit b ngoi ca my tnh, x l tn hiu, h thng lnh v iu khin Nntng cng ngh hin i l k thut vi in t vi mt tch hp ln v rt ln. Khi mun thitk h thng nhng, c nhiu yu t cn tun th ging nh khi thit k my tnh, nhng li brng buc bi c th ng dng. Thm vo l s an cho ca cck nng rt cn thit chothit k h thng nhng, c lp vn hnh, thit k vi tiu ch tiu hao nng lng thp, cngngh phn cng, cng ngh phn mm (h thng v ng dng), h thi gian thc, tng tc

ngi my v i khi c vn an ninh h thng. Nh vy o to v hc h thng nhng cnmt khi lng kin thc tp hp t nht t cc b mn khc nh khoa hc my tnh (computerscience), khoa hc truyn thng (communication), k thut thit k in t: cc mch tng t vs, s dng tt cc phn mm thit k bo mch (nh Protel, Proteus, DXP), kin thc v chto bn dn. V l b mn cng ngh c tnh ng dng cao vi bi ton c th, nn li cn cchuyn mn ca ngnh ngh, m h thng nhng s ng dng. Tm li y l mt ch hp nht v vic thc hin ch ny thc khng d dng.

Vi lng thi gian nht nh, mn hc XY DNG CC H THNG NHNG smang li cho ngi hc nhng vn c bn nht v h thng nhng Chng 1. Chng 2 cp ti kin trc phn cng h thng, cch thit k mt s khi chc nng c s c tnh thc tcao. Chng 3 ch yu gii thiu v phn mm ci t trn h thng nhng, bao gm cc trnhiu khin thit b, cc phn mm trung gian, v phn mm h thng c ci t . c bit nhcli mt syu cu v khi nim ca cc h thng thi gian thc v h iu hnh thi gian thc.Chng 4 gii thiu cc tiu ch v phng php thit k h thng nhng. Cui chng l mt scc bi tp ln kiu D n thit k, c th la chn cho thc hnh vi cc kiu kin trc h thng

nhng khc nhau.

Nh nu, y l ch rng, mang tnh k thut v kin thc li c tng hp t ccmn khc, nn ti liu ny chc khng th tht s y . Cc phn kin thc no khng c cp su y, ngi hc cn tham kho thm cc ti liu khc, hay t cc mn hc lin quan.

Tc gi xin chn thnh cm n cc cn b, ging vin Khoa Cng ngh thng tin v bmn Khoa hc my tnh, Hc vin Cng ngh BCVT H Ni gp tc gi hon thnh giotrnh. Tc gi cng xin n nhn cc kin ng gp, ph bnh t ngi c, ngi hc, sao choti liu ny c ch hn. a ch theo e-mail:[email protected].

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H Ni, thng 10 nm 2013

Hunh Thc Cc,

Vin Cng ngh thng tin, VAST, 18, Hong Quc Vit, H Ni.

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Li ni u ..................................................................................................................................................... 2

Mt schvit tt .......................................................................................................................................... 7

Danh sch cc hnh v.................................................................................................................................... 9

Chng 1. GII THIU CHUNG VCC HTHNG NHNG ........................................................... 15

1.1 KHI NIM VHTHNG NHNG (HTN) ................................................................. 15

1.2 C IM CA HTN ....................................................................................................... 15

1.3 CC YU CU VI HTN ............................................................................................... 18

1.4 M HNH TNG THHTN .............................................................................................. 19

1.4.1 M hnh cu trc phn cng ca my tnh........................................................................... 19

1.4.2 Kin trc ca CPU ............................................................................................................... 23

1.4.3 M hnh tng qut ca mt HTN ......................................................................................... 25

1.4 PHN LOI HTN ............................................................................................................... 27

1.5 KT CHNG................................................................................................................... 32

1.6 CU HI CUI CHNG................................................................................................ 33

Chng 2. CC THNH PHN PHN CNG CA HTHNG NHNG .......................................... 34

2.1 BXL TRUNG TM (Central Processing Unit-CPU)................................................. 34

2.2.1 Cc loi CPU v nguyn l hot ng .................................................................................. 34

2.2.2 V dvmt CPU v nguyn l hot ng .......................................................................... 35

2.2 CPU 8085 V HTHNG BUS ........................................................................................ 44

2.2.1 Khi nim v bn cht vt l ca cc BUS .......................................................................... 45

2.2.2 Khuych i BUS (bus driver)............................................................................................. 47

2.2.3 Bus ng b(Synchronous bus): ......................................................................................... 48

2.2.4 Bus khng ng b(Asynchronous bus) ............................................................................. 50

2.2.5 Trng ti BUS (bus arbitration) .......................................................................................... 51

2.2.6 Bus mrng (Expansion bus) EISA, MCA, Bus cc b, PCI ............................................. 54

2.2.7 Bus SPI (Serial Peripheral Interface ) .................................................................................. 552.2.8 Bus I2C (Inter-Integrated Circuit) ....................................................................................... 56

2.2.9 Thc hin k thut ca BUS ................................................................................................. 62

2.3 BO MCH mt HTN VI CU HNH TI THIU ......................................................... 66

2.4 HTN VI CC CPU KHC NHAU .................................................................................. 69

2.4.1 CPU a nng 16 bit.............................................................................................................. 69

2.4.2 Bo mch vi CPU HARVARD (microcontroller Unit-MCU) hIntel 8051/8052/8xC25173

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2.4.3 Vi mch Hthng khtrnh trong mt Chip (Programmable System on chip-PsoC) vMy tnh thng minh khtrnh (Programmable Intelligent Computer-PIC) ...................... 84

2.5 BNHV THIT KBNH.................................................................................... 98

2.5.1 Mt sthng schnh ca mch nh.................................................................................. 99

2.5.2 Phn loi bnh................................................................................................................ 101

2.5.3 Phn cp bnh................................................................................................................. 108

2.5.4 Tchc bnhvt l v thit kbnh.......................................................................... 110

2.6 GHP NI VI THIT BNGOI VI ............................................................................ 121

2.6.1 Tng quan .......................................................................................................................... 121

2.6.2 Ghp ni CPU chng .................................................................................................... 125

2.6.3 Ghp ni I/O chng ...................................................................................................... 130

2.6.4 Cng vo/ra ........................................................................................................................ 1442.6.5 Ghp ni vi tn hiu tng t(analog signal) .................................................................. 150

2.6.6 Bin i tng tthnh s(sha) ................................................................................... 152

2.6.7 Bin i sthnh tng t(DAC)..................................................................................... 153

2.7 KT CHNG................................................................................................................................ 153

2.8 CU HI V BI TP ................................................................................................................. 153

2.8.1 Cu hi cui chng.......................................................................................................... 153

2.8.2 Bi tp cui chng........................................................................................................... 154

Chng 3. CC THNH PHN PHN MM CA HTHNG NHNG .......................................... 1563.1 TRNH IU KHIN THIT B( vit tt: TKTB)....................................................... 156

3.1.1 Tng quan .......................................................................................................................... 156

3.1.2 Cc loi TKTB................................................................................................................ 160

3.1.3 3.1.3 Hot ng ca TKTB............................................................................................. 161

3.1.4 Pht trin TKTB.............................................................................................................. 161

3.1.5 Mt sv dvTKTB.................................................................................................... 163

3.2 HTHNG NHNG THI GIAN THC ...................................................................... 165

3.2.1 Hiu hnh a nhim (multitasking) ............................................................................... 165

3.2.2 Hthng thi gian thc ..................................................................................................... 184

3.2.3 Hiu hnh thi gian thc (RTOS) ................................................................................. 189

3.2.4 Hthi gian thc khng c hiu hnh thi gian thc ................................................... 195

3.3 PHN MM TRUNG GIAN (middleware) ...................................................................... 198

3.4 PHN MM NG DNG ............................................................................................... 200

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3.5 KT CHNG................................................................................................................. 201

3.6 CU HI CUI CHNG.............................................................................................. 201

Chng 4 THIT KV CI T CC HTHNG NHNG .................................................... 203

4.1 THIT KHTHNG .................................................................................................... 2034.1.1 Cc nn tng c bn khi xy dng kin trc HTN ............................................................. 207

4.1.2 Phn hoch thit kphn cng, phn mm........................................................................ 211

4.1.3 Xy dng bo mch khi pht trin hthng ........................................................................ 217

4.2 CI T V THNGHIM HTN ................................................................................. 221

4.2.1 Chn CPU cho thit k...................................................................................................... 221

4.2.2 Bnhcho HTN................................................................................................................ 223

4.2.3 Ghp ni vi thit b.......................................................................................................... 225

4.2.4 Pht trin phn mm cho HTN .......................................................................................... 2254.2.5 Gri v m phng ........................................................................................................... 235

4.2.6 Pht trin HTN ................................................................................................................... 240

4.2.7 V dpht trin HTN ......................................................................................................... 266

4.3 KT CHNG................................................................................................................. 267

4.4 CU HI CUI CHNG.............................................................................................. 267

TI LIU THAM KHO ...................................................................................................................... 267

PHLC Cc v d .............................................................................................................................. 270

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Mt s ch vit tt

CPU Central Processing Unit n vxl trung tm

ROM Read Only Memory Bnhchi c

EPROM Erasable programmable read-onlymemory

Bnhchc, xa v lp trnh li c

RAM Random Access Memory bnhtruy cp ngu nhin

FLASH

non-volatilecomputer storage

(memory cards,USB flash drives,solid-state drives-SSD)

Bnhbn dn khng bmt ni dung ngay ckhikhng cung cp ngun nui

OS Operating System Hiu hnh

RTOS Real Time Operating System Hiu hnh thi gian thc

ES Embedded System Hthng nhng

HTN Embedded System Hthng nhng

OS hay HH Operating System Hiu Hnh

TKTB Device Driver Trnh iu khin thit b

PLC Programmable Logic Controller biu khin logickhtrnh

PIC Programmable IntelligentComputer

My tnh khtrnh thng minh

PSoC Programmable System - on - Chip Hthng khtrinh trn vi mch

ASIC Application-Specific IntegratedCircuit

ASIC l mt vi mch c thit kdnh cho mtng dng cththeo yu cu c bit

MCU Microcontroller Unit Vi iu khin

CICS Complex Instruction Set Tp lnh y

RISC Reduced Instruction Set Tp lnh rt gn

SPI Serial Peripheral Interface ng lin kt dliu ni tip, ng b, hot ngtheo kiu Ch/t(Master/Slave)

I2C Inter-Integrated Circuit Bus dng ni gia cc vi mch in t

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http://tratu.vn/dict/en_vn/Erasable_programmable_read-only_memory_%28EPROM%29http://tratu.vn/dict/en_vn/Erasable_programmable_read-only_memory_%28EPROM%29http://tratu.vn/dict/en_vn/Erasable_programmable_read-only_memory_%28EPROM%29http://en.wikipedia.org/wiki/Non-volatile_memoryhttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Memory_cardhttp://en.wikipedia.org/wiki/Memory_cardhttp://en.wikipedia.org/wiki/Memory_cardhttp://en.wikipedia.org/wiki/USB_flash_drivehttp://en.wikipedia.org/wiki/USB_flash_drivehttp://en.wikipedia.org/wiki/USB_flash_drivehttp://en.wikipedia.org/wiki/Solid-state_drivehttp://en.wikipedia.org/wiki/Solid-state_drivehttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://www.cypress.com/psochttp://www.cypress.com/psochttp://en.wikipedia.org/wiki/Complex_instruction_set_computerhttp://en.wikipedia.org/wiki/Reduced_instruction_set_computerhttp://en.wikipedia.org/wiki/Reduced_instruction_set_computerhttp://en.wikipedia.org/wiki/Complex_instruction_set_computerhttp://www.cypress.com/psochttp://vi.wikipedia.org/w/index.php?title=B%E1%BB%99_%C4%91i%E1%BB%81u_khi%E1%BB%83n_logic&action=edit&redlink=1http://en.wikipedia.org/wiki/Solid-state_drivehttp://en.wikipedia.org/wiki/USB_flash_drivehttp://en.wikipedia.org/wiki/Memory_cardhttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Non-volatile_memoryhttp://tratu.vn/dict/en_vn/Erasable_programmable_read-only_memory_%28EPROM%29http://tratu.vn/dict/en_vn/Erasable_programmable_read-only_memory_%28EPROM%29


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USART Universal Serial AynchronousReceiver/Transmitter

Bthu/pht ni tip di ba nng

ISR Interrupt Service Routine Chng trnh con xl ngt hay Dch vxl ngt

MAC Media Access Control iu khin truy nhp mi trng (mng my tnh).V d:MAC address: a chvt l ca thit bmng.

MIPS Million instructions per second Triu lnh my trong mt giy

IDE

Integrated DevelopmentEnvironment, hoc:

Integrated Design Environment

hoc:

Integrated DebuggingEnvironment

L tp cc phn mm h tr cc cng c, tin ch pht trin phn mm my tnh, bao gm:

Son tho m ngun, trnh thng dch, trnh bindch, trnh gri

ICE In-Circuit Emulator

L loi thit bphn cng dng gri khi phttrin phn cng v phn mm hp nht, nh HTN.Vid dnh Logic anlyzer, phn mm MPLAB caMicrochip

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Danh sch cc hnh v

Hnh 1.1 M hnh tng qut bo mch ch

Hnh 1.2 Ngun nui cho hmy tnh

Hnh 1.3 HTN xy dng txy dng tvi xl(Microprocessor-based) v vi iu khin

(microcontroller based)

Hnh 1.4 Microcontroller v cc thnh phn c bn, BUS kt ni bn trong.Tt ctrong mt

chip

Hnh 1.5 Hai kiu HTN vi 2 loi kin trc CPU

Hnh1.6 Havard CPU ARM 920T ca Amtel

Hnh 1.7 M hnh tng qut HTN-M hnh vi cc khi chc nng

Hnh 1.8 Mt cch nhn khc vm hnh tng qut HTN:Vi cc khi ngoi vi v phnmm

Hnh 1.9 Kin trc tru tng HTN

Hnh 1.10 S khi CPU DSP-MP3.

Hnh 1.11 BMP3 vi CPU BlackFin ca ANALOG DEVICES

Hnh 1.12 Mt sHTN thng mi

Hnh 2.1 Intel CPU 8085

Hnh 2.2 Cc khi chc nng ca CPU 8080/8085

Hnh 2.3 Cc khi nin qui chiu theo CPU Clock

Hnh 2.4 Lu thi gian c sca CPU 8085 (Theo ti liu ca hng Intel)

Hnh 2.5 Biu thi gian ca chu k tm lnh.

Hnh 2.6 Cu hnh ti thiu: CPU 8085 v to BUS hthng

Hnh 2.7 CPU Bus v BUS hthng

Hnh2.8 Chu k c ng b

Hnh 2.9 BUS khng ng b, hot ng ng bbi i thoi gia cc tn hiu iu

khin

Hnh 2.10 BUS chui quay vng (daisy chaining)

Hnh 2.11 Trng ti BUS

Hnh 2.12 Trng ti Bus khng tp trung trong multibus

Hnh 2.13 Lin kt qua bus SPI

Hnh 2.14 Lin kt qua bus I2C

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Hnh 2.15 Nguyn l ni BUS I2C

Hnh 2.16 Ghi/c trn BUS I2C

Hnh 2.17 V ddliu thu/pht trn BUS I2C

Hnh 2.18 Cc mch logic thng dng trong thit kk thut sHnh 2.19 Cc kiu ni u ra, u ra trkhng cao

Hnh 2.20 Vi mch 3 trng thi: hai trng thi logic v

trng thi th3 HZ: u ra btchkhi BUS.

Hnh 2.21 Mch cht (hay nh, gi li) kiu D,

lm vic theo mc hay sn ln ca xung ng hCK. (Xem thm chi tit mach

SN 7474).

Hnh2.22 Cht 4 bit vi D-Flip/flop

Hnh 2.23 Cng khuych i (driver) cht hai chiu

Hnh 2.24 Cu hnh ti thiu bo mch CPU 8085, RAM/ROM/Ports

Hnh 2.25 Mch in cho hnh 2.24

Hnh 2.26 CPU Intel x86

Hnh 2.27 Bo mch vi ti thiu vi CPU 8086:BUS controller, Ngt controller, RAM

Hnh 2.28 CPU 8086 timing: lnh c

Hnh 2.29 M hnh kin trc Havard:

BUS cho bnhchng trnh: Code Bus v Code Address;

BUS cho RAM dliu: Data Bus v Data Address;

SRC1, SRC2:ngun, DST: ch, l cc Bus ni b.


Hnh 2.31 CPU 8051: EEPROM, RAM bn trong

v khnngmrng bnhti 128 KB (64 KB code+64 KB data)

Hnh 2.32 Bo mch vi CPU 8051/8052

Hnh 2.33 Cc khi chc nng ca nhn 8XC251SxHnh 2.34 CPU 8051

Hnh 2.35 Phn hoch a chtrong CPU 8051

Hnh 2.36 Bo mch vi CPU Intel 8051 v RAM, ROM mrng bn ngoi.

Hnh 2.37 M hnh mt vi iu khin kiu PSoC hay PIC kiu Vi xl trong mt Chip

(Microprocessor-based system on a chip)

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Hnh 2.38 Vi iu khin PSoC CY8C29466

Hnh 2.39 Btr v-chn PIC 12F675

Hnh 2.40 M hnh khi chc nng PIC12F629/675

Hnh 2.41 Vi iu khin PIC 16F882/883/88Hnh 2.42 Cch to bit nhcnh bng cng tc c hc hay diode bn dn

Hnh 2.43 M hnh u vo/ra ca phn tnh

Hnh 2.44 Cch tchc 1 n vnhchun (1 byte) tcc phn t1 bit, 4bit v 8 bit

Hnh 2.45 Phn loi bnh

Hnh 2.46 Cc loi bnhROM

Hnh 2.47 Cc loi RAM

Hnh 2.48 1 phn tRAM tnh

Hnh 2.49 1 chip RAM 32K x 8 (32K byte)

Hnh 2.50 Phn tDRAM, 1 bit DRAM v ma trn DRAM

Hnh 2.51 Cc cch ghi/c/lm ti ca DRAM

Hnh 2.52 Phn cp bnh

Hnh 2.53 M hnh hot ng ca RAM cache

Hnh 2.54 S v ngoi mt vi mch (chip) nh(pin-out)

Hnh 2.55 S khi chc nng bn trong chip 16K x 1 bit

Hnh 2.56 S thit kbng nhSRAM 16K x 8, vi Chip 16Kx1

Hnh 2.57 S khi chc nng ca 1 chip DRAM thng mi 4164Kb

Hnh 2.58 Quan hcc tn hiu iu khin DRAM 4164x1 thng mi.

Hnh 2.59 CPU 8080/8085 Module DRAM 64 KB ton phn

Hnh 2.62 V dvcch phn bbnhtrong my tnh PC

Hnh 2.63 M hnh k thut ghp ni

Hnh 2.64 Cc kiu ghp ni

Hnh 2.65 c dliu vo: Dliu_tthit bvo ACC sau vo RAMHnh 2.66 a dliu tRAM vo ACC sau ACC ra thit b

Hnh 2.67 Trao i d liu c vo c iu kin

Hnh 2.68 Lu iu khin c d liu v c iu kin

Hnh 2.69 Lu iu khin c d liu kiu quay vng

Hnh 2.70 M hnh hot ng ca ngt

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Hnh 2.71 Cc kiu ngt

Hnh 2.72 Thit kt vi ngt cng che c INTR ca CPU

Hnh 2.73 Vector ngt v chuyn xl ti ISR

Hnh 2.74 T chc ngt vi iu khin ngtHnh 2.75 Mrng sngt vi 2 vi mch 8259

Hnh 2.76 Nguyn l DMA

Hnh 2.77 DMA v hot ng ca CPU l c lp

Hnh 2.78 Ghp ni DMAC 8237 vo vi CPU 8085v lu thi gian ca qui trnh DMA

Hnh 2.79 Lu DMA ghi dliu tRAM ra thit bngoi

Hnh 2.80 nh ngha cc chn ca cng SSP

Hnh 2.68 Cng song song trn PC v gii ngha cc chn cngHnh 2.81 Lu cc tn hiu cng song song

Hnh 2.82 Cng song song hai chiu

Hnh 2.83 u ni RS 232 cc loi DB9, DB 25 v DEC MMJ

Hinh 2.84 PC lm hpht trin phn mm cho HTN, ph hp tn hiu gia RS-232 cua PC

v cng SI-P ca HTN ang pht trin

Hnh 2.85 Cng SI-P n gin, dng ngun tRS 232 ca PC

Hnh 2.86 ADC v ghp vo HTN

Hnh 2.87 HTN v DAC

Hnh 2.88 Bi tp thit kghp ni ADC, cng LPT vo my tnh PC

Hnh 3.1 M hnh tng qut cc phn mm trn my tnh

Hnh 3.2 M hnh tng qut cc kiu sp xp phn mm trn my tnh

Hnh 3.3 Trng thi ca tin trnh

Hnh 3.4 Trin khai API qua GHT

Hnh 3.4 Nguyn l a trnh v quan hgia chngi dng v chnhn HH

Hnh 3.5 Cc kiu tc vHnh 3.6 Hu ht cc loi tc vxuyn qua lp biu.

Hnh 3.7 Biu thc hin mt tc v

Hnh 3.8 Phn loi cc gii thut lp lch thc hin tc v

Hnh 3.9 Quay vng kt hp u tin v chen ngang

Hnh 3.10 M hnh nguyn l cho WD

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Hnh 3.12 Skin v p ng

Hnh 3.13 RTOS nhn thi gian thc v RTOS a nng

Hnh 3.14 Module lp biu ca nhn HH

Hnh 3.15 Cc chc nng nhn RTOSHnh 3.16 Cc hiu hnh RTOS

Hnh 3.17 Hthng nhng thi gian thc

Hnh 3.18 Vtr cua PMTG HTN

Hnh 3.19 M hnh cc lp mng theo TCP/IP, OSI v nh xvo HTN

Hnh 3.20 Cc ng dng WEB trong HTN, t lp phn mm ng dng

Hnh4.1 Cc thuc tnh chung ca phn cng ca mt HTN

Hnh4.2 Mt kiu c ttin thit kHTN

Hnh 4.3 Kch bn m phng hiu nng khi thit kHTN

Hnh 4.4 Cc cu trc kiu 4+1

Hnh 4.5 Cc pha thit kHTN

Hnh 4.6 Gii thut thit kmy in laser: phn hoch cng/mm

Hnh 4.7 Phn hoch thit kphn cng v phn mm

Hnh4.8 ng thit kphn cng v phn mm-ng kim nghim, ti uthit k

Hnh4.9 Qui trnh thit kkiu ASIC

Hnh 4.10 Xy dng m hnh hnh thc: Bc sng lc sdng cch tng hp phn cng

v phn mm chuyn ha xc nh chc nng vo m hnh phn cng ca thit

k.

Hnh 4.11 Bo mch HTN

Hnh 4.12 Mi tng quan gia gi thnh hthng/hiu nng

v mc tch hp thng/hiu nng

Hnh 4.14 Qu trnh bin dch thnh m ma to ra HH

Hnh 4.15 nh dng mt tp thc thi ELFHnh 4.16 Tng qut cc bc to nhn HH mi tm ngun

Hnh 4.17 Tng qut cc bc to nhn HH mi tm ngun v kiu khi ng

Hnh 4.19 Cc loi cng chtrgri

Hnh 4.20 Kt quhin thca gri

Hnh 4.21 Lin kt gihpht trin v hch ang c gri

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Hnh 4.22 Mi trng pht trin cho: hpht trincng c- HTN ch

Hnh 4.23 Hthng nhng : phn mm nhng v phn cngnhng

Hnh 4.24 Hpht trin HTN

Hnh 4.25 Qui trnh pht trin phn mm ch np vo HTN ch.Hnh 4.26 Qui trnh pht trin phn mm cho HTN

Hnh 4.27 Sn gin hthng v nh xbnhvo EEPROM hay FLASH ca HTN

ch.

Hnh 4.28 Vai tr ca trnh loader

Hnh 4.29 Phn program header table chra cc phn on c sdng lc chy chng

trnh (run time) v phn header lit k tp cc phn nhphn : .text: m chng

trnh, .rodata: dliu chc, .data: dliu c/ghi c.

Hnh 4.30 nh xthc thi chuyn vo bnhca hthng

Hnh 4.31 V dtng quan vboostraphthng

Hnh 4.32 Trnh tboot boot image chy tROM

Hnh 4.33 Trnh tboot thc hin RAM sau khi image c copy tROM vo RAM

Hnh 4.34 Chy image sau khi ti xung hch thpht trin (PC)

Hnh 4.35 Tin trnh khi ng phn mm HTN

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Chng 1. GII THIUCHUNG V CC H THNG NHNG

1.1 KHI NIM V H THNG NHNG (HTN)

Nhn li nhng nm 70 thktrc, xl thng tin thng phi sdng cc my tnh ln haymy tnh mini (v ddng my mini PDP 11 ca hng DEC mt hthng thng trtrong truynthng). Cho ti nhng nm 80, khi vi xl v my tnh c nhn (PC bn v xch tay) ra i,my tnh trthnh cng cc dng cho xl thng tin bi khnng tnh ton nhanh, gn nhv di ng linh hot. Giai on tip theo l khnng chto vi mch kch thc vi trm micromt v nano mt ca nhng nm chn mi, thc y xu hng nhha (miniaturization) va dng cc dng vi xl, pht trin mnh m. Cc bvi xl a nng v sxut hin cc vi xl chuyn bit (ASIC- application-specific integrated circuit) c chto vi slng ln chatng thy. Vic sdng cc bvi xl chuyn bit to ra cc thit bchuyn xl mt haymt vi bi ton k thut, to ra mt nghnh cng nghmi, gi l cng nghnhng. Sn phm

ca cng nghnhng ny l cc hthng nhng.Vy hthng nhng (HTN-Embedded system) l g ?C nhiu nh ngha vHTN, nhng nu ta ly tiu ch m tHTN lm ci g v sdng n nhthno, th c thni vHTN nh sau:

Hthng nhng l mt thut ngchmt hthng c khnng hot ng ttrcnhng vo trong mt mi trng hay mt hthng khc qui m phc tp hn. l cc hthngtch hp cphn cng (l mt h thng my tnh c xy dng trn c ssdng vi x l -microprocessor-based system) v phn phm nhng trong phn cng , thc hin cc biton chuyn bit.

Hay theo nh ngha ca tchc IEEE th hthng nhng l mt htnh ton (my tnhs) nm trong (hay c nhng vo) sn phm khc ln hn v rng thng thng n i vingi sdng. Ni rng ra, v n gin hn, khi mt htnh ton (c thl PC, IPC, PLC, vi xl, vi h thng (microcontroller), DSP v.v...) c nhng vo trong mt sn phm hay mt hthng no v thc hin mt schc nng cthca hthng , th ta gi htnh ton lmt hthng nhng. Tuy nhin tht khng dg nh ngha cho tht ng vHTN, nh nghatrn rt t ni ti cng nghv cng rt n gin. Hin nay cha c nh ngha no tht tha ngvHTN, v dnu ly chc nng x l thng tin, th HTN l mt phn x l thng tin nhngtrong cc hthng ln hn v phc tp hn, hay cng c thl mt hthng c lp vn hnh tng. V dgn gi ta c: my tnh c nhn, hay my ch, l mt hthng phc tp c xy

dng tcc thnh phn hot ng c lp nhng c ng bvi nhau. V iu khin ha,c vi iu khin rt mnh xl ha, v iu khin trn a cng c vi iu khin chuyn dngxl tn hiu, ghi/c dliu ta ttnh theo yu cu ca hiu hnh, v mng cng lmt vi iu khin tinh vi xl tn hiu l cc hthng con c nhng trong hthng mytnh ni chung. Mc d vy ta cng snu ra y mt sim chung vHTN.

1.2 C IM CA HTN

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hiu r hn vHTN, ta nu ra mt sc im nhn bit vmt hthng nhng:

L mt kiu my tnh ng dng c bit, rt gii hn vphn cng v phn mm khi sosnh vi cc my tnh a nng, nh my tnh c nhn, my ch, siu my tnh. iu ni

ln rng hiu nng xl, nng lng tiu th, bnh, cc phn cng khc u hn ch. Cnphn mm hn ch, hay phn mm l cnh, c ngha hiu hnh c thit kph hp

vi cc xl nh. Hin nay hiu hnh thng sdng l hiu hnh a nhim (nh

DOS 6.X htra nhim trn cc loi HTN dng PC 104), hay hiu hnh thi gian thc.Nu khng c hiu hnh, th cng l mt kiu chng trnh iu khin chung (monitor)no . Phn mm vit ra khng c cc phn m c mc tru tng hay c cng mcthp. M thc thi (gm hiu hnh v cc ng dng) c np vo bnhROM. Nhnchung m thc thi c kch thc nhv ti u v ROM c dung lng nh. Tuy nhin vi spht trin nhanh chng ca cng ngh, cch nu trn c ththay i, bi sc cc HTN rttinh xo v mc phc tp rt cao, bnhc thn vi chc mega bytes.

HTN c thit kthc hin mt hay vi ng dng xc nh, chuyn bit (Applicationspecific), v dcc thit bnhng cng nghip nh robot thuc loi ny. Tuy nhin c nhngthit b nhng khc nh cc PDA, in thoi di ng, l cc HTN c kh nng thc hinnhiu chc nng hn. Hay cc Tivi k thut sli c ththc hin cc ng dng tng tcvi mn hnh cm ng, v.v Tuy nhin xu hng hin nay l to ra cc HTN khtrnhcgiao din kt ni vi mt hpht trin khc nng cp phn mm.

HTN tng tc vi mi trng ng dng qua nhiu phng thc:

Qua cc bcm bin (sensor), ghp ni vo HTN bng dy dn, hay khng dy; Pht trin cc giao thc truyn tin ring bit, hay theo cc giao thc chun trao

i thng tin vi cc thit bkhc, c thc htrni mng LAN; HTN thuc loi thit bthng minh tphn ng(reactive), bng nhng tng

tc lin tc vi mi trng v c p ng kp thi vi nhng tin trin (skin)m mi trng xc lp.

Tng tc ngi-my rt n gin nu c v HTN chy c lp v thng tin vi hthng ln hn l chnh. Ngy nay xu hng WEB ha giao din tng tc l phbin, v dcc thit bkt ni mng Internet nh ADSL dng SOHO (SmallOffice-Home Office), c WEB lm cu hnh v qun tr. Tng t, cc HTN

cng nghip cng pht trin theo xu hng ny dqun trttrung tm iukhin.

HTN hot ng c lp, do ccc im sau y: tin cy, l tng l khng c s chng hc. Bo tr: thi gian bo tr nhanh chng. C tnh sn sng cao, l kt quca stin cy v bo tr.

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An ton: nu c scxy ra, HTN khng gy ra nhng tc hi khc ca ton hthng.

An ninh: dliu ca HTN c bo mt, truy nhp phi c xc nhn (v d, HTNl cc thit btruyn thng, SOHO).

HTN l mt kiu my tnh c yu cu vcht lng v tin cy rt cao, hot ng c

trong cc mi trng khc nghitvnhit (cao, hay rt thp), m cao, rung ngln, nhiu sng in tv.v V dcc my tnh trong cng nghip, cc thit btruyn thng,trm BTS chng hn, hay cc my tnh iu khin trn my bay (fly by wire)

Phn ln cc hthng nhng hot ng visrng buc thi gian: yu cu c thi giancho (p ng) u ra nhanh, ng thi im, trong mi tng quan vi thi im xut hinca (skin) u vo. Kiu hot ng nh vy gi l to p ng theo thi gian thc. Thigian thc c thchia ra lm hai kiu:

Nhy cm vi thi gian (time- sensitive): skin chc xl trong mt khung

thi gian nht nh;

Thi gian ti hn (time critical): khi c s kin, h thng phi phn ng ngay,

chuyn nhanh nht n m chng trnh ng vi s kin x l, ni cchkhc trong mt ca s thi gian cho php, x l phi c thc hin v phi cp ng u ra. V dnu vng phn hi trong cc hc iu khin HTN l

biu khin chy gii thut iu khin khng nhanh (xl, tnh ton qu lu),hthng trnn khng n nh.

C hiu nng cao. Cc sosau y se phn nh c tnh ny: Sdng nng lng thp v hiu qu. C ththy im ny cc thit bdi ng. M phn mm c kch thc rt ti u, v m phi ci ton btrn HTN. Thi gian xl tc v(run-time) phi nhanh, sdng t ti nguyn phn cng (v

lin quan ti tiu hao nng lng). Trng lng nh. y l mt trong nhng lc chn khi mua mt HNT. Gi thnh rt cnh tranh. Mun vy thit kv sdng phn cng, phn mm cn

quan tm ti hiu qu.

Di y l cc v dvcc HTN nhn gc sdng:

Lnh vc ng dng Thit bnhng

t nh la in t, iu khi n ng c, hthng phanh, hs

in ttiu dng Tivi analog, Tivi s, CD, DVD, VCR,

PDA, in thoi di ng, CAMCODER, GPS, tiu ha, t

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lnh, l vi sng

Cng nghip Robot, dy chuyn sn xut tng, SCADA agents

Y t My thm tch, my pha-lc, my th, my trtim, my qut ctlt, rt nhiu thit by thin i

Mng thng tin (WAN, LAN, thoi) Bnh tuyn, gateway, chuyn mch mng, cc thit btruynthng-mng, trm chuyn tip, BTS di ng

Vn phng My Fax, my potocopy, my in (kim, laser, phun), my qut, mnhnh LCD

Cc lnh vc khc: an ninh, qucphng, hng khng, hng hi

c hp nht trong rt nhiu kh ti hin i ca tt ccc binhchng .

1.3

CC YU CU VI HTN

HTN thc tl mt loi my tnh dng xl thng tin dng s. HTN c thlmt h thng c lp nh mt thit b tch cc trong m hnh iu khin, tc HTN l mtregulator s, thc hin cc chc nng caPID regulator, khi cc chc nng ny c thhinbi thut ton v chuyn ha dng m chng trnh trong HTN. Trong khi HTN li l mtphn ca mt qui trnh cng nghtrong cng nghip. Nh trn lit k cc c im chung mcc hthng nhng thng c, tnhin ta c thrt ra c nhng yu cu cn c trn mt hthng nhng.

1.

Khnng p ng vi s kin bn ngoi (t cc tc nhn b kim sot) phi nhanh

nhy, kp thi, tc l khnng theo thi gian thc:

Cc tc vc p ng rng buc bi thi hn cht (deadline);

Thi gian pht hin li phi rt ngn (ti thiu);

Khi chy cc chu trnh vng lp iu khin bng phn mm phi c p ngu ra ng thi hn;

2. C khnng lm mi trng khc nghit.

3.

Cgi thnhthp hay hiu quhot ng/gi thnh hp l.

4. Kch thcnhgn,nh, dmang dvn chuyn, lp t.

5.

Tiu thnng lng thp, khnng sdng ngun pin, c qui (tt nhin phthuc vodung lng ca pin, c qui).

6. Hot ng tin cy, chu li cao

Tin cy: p ng dch vyu cu ng thi hn sau thi gian tt0n t;

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Cho hng sca tssctrong thi gian 1 ging hl e (e/h), th biudin t s s c l R(t)=exp(-e(t-t0)), sau thi gian gia 2 ln s c (MeanTime To Failure- MTTF) sl 1/R(t);

tin cy cao nu t ~10-9sc/gi.

Tnh sn sng cao: Nu thi gian sa cha sc trung bnh l MTTR, th tnhsn sng (availability) A=MTTF/(MTTF+MTTR).

7. An ton v bo mt.

8. Khnng nng cp phn mmv dphng nng cp phn cng (m rng qua khecm dtr, v dcc thit bmng thng c tnh nng ny).

1.4

M HNH TNG TH HTN

Nh nu trong nh ngha ca HTN, th HTN c kin trc ca mt my tnh s, do vy skhng c g khc bit khi m tm hnh kin trc ca HTN ni chung. C khc chng l chitit ca tng HTN cth.

1.4.1 M hnh cu trc phn cng ca my tnh

Di y ta nu ra m hnh tng qut ca my tnh theo nguyn l Von Neumman. HTN cngchia skin trc ny trong mt strng hp. M hnh cho thy cc khi chc nng c bn cnc. Trong thc tc nhng CPU nhng c kin trc cthkhc nhau, nhng khi m tcc khichc nng, th hon ton thng nht.

M hnh ly n vxl trung tm (Central Processing UnitCPU) l khi chc nng c bn

nht to nn mt hvi xl, HNT hay my tnh c nhn (Personal ComputerPC). CPU thc hin chc nng xl dliu theo nguyn tc thc hin chng trnh my

tnh ci trong bnhROM hay np vo bnhRAM. Vic thc hin nh sau: CPUc m lnh (OPCODE) tbnh(ROM hay RAM), sau ,

Gii m lnh, to cc tn hiu (xung) iu khin tng ng vi m lnh iukhin hot ng ca cc khi chc nng khc trong CPU v bn ngoi CPU.

Tp cc tn hiu to ra BUS ca CPU. Khi kt hp vi cc vi mch dn /tchknh v khuych i, cc mch gii m, sto ra BUS hthng. BUS hthngcung cp cc tn hiu cho cc vi mch tch hp vo CPU (ROM, RAM, I/O

module) to thnh bo mch chnh (CPU board). Thc hin tng bc cc thao tc xl dliu nh ngha trong m lnh.

Ghi li kt quthc hin lnh.

B nh chnh (ROM/RAM) c t chc t cc t nh n, kp. Theo chun caIBM/PC tnh n c s) c di 1 byte (8 bits). Bnhny gm cc chip nhch c ROM (Read Only Memory) v cc chip nh truy xut ngu nhin RAM(Random Access Memory) c tc truy cp nhanh. Bnhc sdng cha

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cc chng trnh v cc dliu cn xl. Cc chng trnh ng dng v dliu cthc cha ROM hoc RAM, cc kt qutrung gian hay kt qucui cng cacc thao tc xl c thc cha trong cc thanh ghi a dng hoc trong RAM.

B vi x l trungtm

(CENTRAL

PROCESSING

UNIT)

ng h thch

anh nhp chun

Ngun nui mtchiu

H thng ng dy d liu (DATA BUS)

H thng ng dy iu khin (CONTROL BUS)

H thng ng dy a ch (ADDRES BUS )

B nh Ghi/c(RAM) B nh ch c(ROM)

Ghp ni ra (O) Ghp ni vo (I)

BUS

hthng

Hnh 1.1- M hnh tng qut bo mch ch

Cc mch ghp ni vo/ra (I/O interface) l cc mch in t, thc hin cc gii php kthut thch ng tn hiu, trkhng cho php CPU trao i dliu vi cc thit bngoivi nh bn phm, mn hnh, my in, cc bchuyn i s-tng tDAC (Digital/Analog

Converter), chuyn i tng t-sADC (Analog/Digital Converter), cc mch vo/ra dliu dng sDO (Digital Outputs), DI (Digital Inputs)

Hvi xl cn c mt mch to xung nhp gi l CPU Clock. Bto xung ny c iukhin bng mt mch thch anh c tn sthch hp v m bo tn slm vic n nh,vi tn schnh xc cao. CPU c mt chn pht xung cho cc vi mch cn li, gi l nghhthng (SystemClock), ng hny ni ti tt ccc vi mch iu khin chnh trnbo mch, ng bton bhot ng vi CPU.

Mt khi ngun nui (Power Supply) cung cp nng lng cho h thng tmng inli, hay sdng pin. Bngun ca cc hvi xl thng thng l bngun xung vi

kthut ng-ngt dng linh kin bn dn cng sut (Switching Power Supply), va gnnh, cng sut ln, hiu sut cao.

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Hnh 1.2-Ngun nui cho hmy tnh

Phn loi trn c svi mch

Tuy nhin khi cp ti cu trc ca HTN c xy dng trn cng nghvi mch, c thc hai loi khc bit:

Vi iu khin (Microcontroller )v vi x l (microprocessor)khc nhau theo vi cch, trcht l chc nng. sdng mt vi x l, cn hp nht nhiu thnh phn vo : b nh, I/O,COM v do vy vi x l l trung tm ca c h thng. Trong khi vi iu khin c thit ktheo tiu ch: tt c c tch hp trong mt vi mch, c bit l cc giao tip I/O, tc l s khngcn thm thnh phn no vo . Li ch l ch tit kim thi gian thit kv kch thc snh gnrt nhiu. Tuy nhin do phn cng hn ch, nn lnh vc ng dngcng phi c xcnh.

Hthng nhng da trnbvi xl trn bo mch

(Microprocessor-based

Embedded System)

Hthng nhng vivi iu khin trn bo mch

(Microcontroller-based

Embedded System)

C CPU c lp, c thl CPU anng phbin (Intel 8080/8085,Motorola 6800),

C RAM, ROM, nh thi , I/Oc lp,

Khnng mrng RAM, ROM,I/O ty ,

a nng, t tin.

Kin trc gn nh mt my tnh

CPU dng li chuyn bit, RAM,ROM, nh thi, I/O trong mt vi mchn,

RAM, ROM c dung lng cnh,I/O cho mc ch sdng,

n mc ch, ng dng xc nh,tiu hao t nng lng, gi chp lcho ng dng nhng.

Kch thc nh, gn.

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nhng c kch thc nh.

Thit kchc nng:

Cn phi c cc vi mch RAM,

ROM hp thnh tbn ngoi vi mch. Khng thkt ni vi ngoi vingoi vi, cn c thm cc vi mch htrcho chc nng ny.

Tuy nhin nng lc tnh ton

mnh.

Thit kchc nng:

c thit kc tt ctrongmt Chip !

Nng lc tnh ton c thit ktiu cho ng dng xc nh, cc ngdng chuyn bit.

Rt ph hp xy dng cc HTN

Tit kim gian thit k.

Hnh 1.3 HTN xy dng txy dng tvi xl(Microprocessor-based) v vi iu khin

(microcontroller based)

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Hnh 1.4 ChipMicrocontroller v cc thnh phn c bn,BUS kt ni bn trong.Tt c trong mt chip.

1.4.2 Kin trc ca CPUPhn nhiu cc ti liu khi cp ti thit kHTN, u dnh mt schvkin trc v cch

thit kchto CPU. y l mt vn chuyn v rt su, ti liu ny skhng dn xut. Tiliu chgii hn gii thiu cc kiu CPU c thsdng thit kHTN. Cc kiu CPU ny rtphbin trn thtrng, rt a dng vi nng lc xl khc nhau v ph hp cho mi loi ng

dng nhng. Di y l mt trong cc quan im nhn nhn CPU:

Tp lnh: c thl CISC hay RISC, trong RISC l phbin. Hot ng theo kiu Von Neumman, v din hnh nh hnh vtrn, trong H

thng BUS a chv BUS d liu, BUS iu khin chung cho ton bh thng, b

nh chia s chung cho ton h thng vi vng m lnh (code) v d liu (data) trncng khng gian a chbnhv BUS dliu khng thtruyn ng thi m lnh v

dliu cng mt thi im. Qu trnh thc hin mt lnh my nh sau:1) c m lnh tROM/RAM qua BUS dliu vo CPU, gim xc nh lm

g tip theo;2) c dliu tip theo l mt phn ca lnh (operands) nu c;3) Thc hin lnh khi c ht cc operands ca lnh;4) Lu kt quvo thanh ghi hay ra RAM.

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Trong qua strnh thc hin lnh, BUS dliu l knh duy nht trao i dliu, dovy ta ni BUS d liu c thbbo ha, hiu nng tnh ton bhn ch. Vi ccCPU hin i BUS dliu c ci tin rt nhiu, c bit l giao thc BUS v ng

hBUS c nng cao ci thin hn chni trn.

V hot ng kiu Harvardvi mt sc im khc bit : Howard Aiken (1900-1973) khi xy dng my tnh vi cc rel tch cc bnh

d liu (RAM) v b nh chng trnh (NVM Non Volatile Memory: ROM,FLASH) vi cc bus ring r truy cp vo bnhd liu (RAM) v b nhchng trnh cha phn mm nhng (h iu hnh, Device drivers, ng dng

nhng ). Bus cho lnh v Bus cho dliu tch bit, iu hnh c lp nn lnh v dliu c

thc a ra cng mt lc, ci thin tc so vi thit kvi chmt bus.

Phn bit r rng bnhdliu v bnhchng trnh, CPU c thva c mtlnh, va truy cp dliu tbnhcng lc. Do cc BUS c lp, CPU c khnng tm trc cc lnh (instruction prefetch),

nn vi kin trc Harvard chng trnh chy nhanh hn, bi v n c ththc hinngay lnh tip theo khi va kt thc lnh trc .

Tuy nhin vkin trc c phn phc tp hn trong phn cng, vi 2 BUS c lpgy kh khn nht nh cho cc ngn ng lp trnh cp cao (v d nh C, )nhng cho hiu quhn cho cc ng dng nhng. L loi phbin thit kccHTN.

Hnh 1.5 Hai kiu HTN vi 2 loi kin trc CPU

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V dHavard CPU ARM 920T, l loi CPU ci tin vi mt nhcache cho lnh v mt cache cho d

liu.

Hnh1.6 Havard CPU ARM 920T ca Amtel

1.4.3 M hnh tng qut ca mt HTN

Cc khi chc nng:

- Mi trng hot ng: ni sdng HTN,

- Chp hnh: l cc thit bcng ngh,

- Cm bin: thit bc bit ghi nhn thng tin cng ngh(vtr, vng quay, tc ,nhit , p sut, kch thc (cao, di, su) ) ,

- Ghp ni: l cc thit bphi hp, chuyn ha cc thng tin tcm bin thnh tn

hiu in sha,

- Cc bsha (A/D) v tng tha (D/A),

- Ghp ni vi cc hthng khc: lin kt cc HTN khc, mng dliu, Trung tmiu khin SCADA,

- Ghp ni BUS hthng

- CPU, RAM, ROM (FLASH),

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Hnh 1.7 M hnh tng qut HTN-M hnh vi cc khi chc nng

Hnh 1.8 Mt cch nhn khc vm hnh tng qut HTN:Vi cc khi ngoi vi v phn mm

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Kin trc tru tng: lp xp chng

Khi ni vkin trc mt hthng, thng ta cp tnh tng qut v nhng chc nngc bn. Nh vy mc tng qut, cc lp phn cng v phn mm c cp nh cc

thnh phn (element) hp thnh. Cc thnh phn kin trc c th hp nht bn trong thit bnhng hoc tn ti bn ngoi v tng tc vi cc thnh phn bn trong theo mt cch no . cch nhn kin trc, th kin trc c biu din bi cc cu trc. Mi cu trc bao gm mt tphp cc thnh phn c trng, cc thuc tnh v nhng c t vmi quan h bn trong ccthnh phn .

Kin trc lp xp chng c c tnh l mi lp chsdng chc nnghay dch v) catng di n,ng thi chcho php tng trn sdng cc chc nng dch v) ca mnh. Kintrc ny c li thvan ninh, bn vng, n gin vthit k, dnng cp (cc dch v), thchin mi lp v khnng nng cp nng ngay ckhi hthng ang hot ng. V dnguyn lny ta thy m hnh mng chun OSI (Open Systems Interconnection), kin trc ca hiu

hnh Unix/Linux.M hnh mt NTH cng c c t theo lp kin trc m bo vtin cy, n

gin khi hot ng:

Hnh 1.9 Kin trc tru tng HTN

-Lp phn cng: Nh Cc khi chc nng.

-Lp phn mm hthng: Hiu hnh hay Monitor

-Lp ng dng: L mt schng trnh ng dng xc nh m HTN thi hnh.

1.4

PHN LOI HTNPhn loi HTN c ththeo nhiu tiu ch khc nhau v c thkhng hon ton ging nhau (gingnh khi nu nh ngha vHTN). Tuy nhin c thnu ra y mt stiu ch phn loi HTN. HTN hot ng u:

Hot ng c lp: nhn u vo tcc tc nhn biu khin, xl v cho u ra.Thi gian c u ra (p ng) phi trong mt khung thi gian nht nh theo khithit k.

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Hot ng c lin kt vi nhau gia cc HTN v cc trung tm kim sot khc. Loiny gi l HTN mng. V dcc HTN cc bti cc thit bchp hnh u cui camt qui trnh cng nghphc tp lin kt qua mng cc bca nh my hay ca mtcmy phc tp. H thng mng in thoi di ng l mt v dkiu HTN mng:

my ngi dng cc trm BTS tng i tng i BTS myngi dng. Tn chung ca HNT li ny l HTN di ng.

Lnh vc ng dng:

Cng ctnh ton nh cc my tnh nhng chchy cc bi ton nht nh.

Xl tn hiu: cc thit bvideo thi gian thc, DVD player, thit by t

Truyn thng, mng: thit bmng nh router, chuyn mch (switch), firewall.

Hthng iu khin v thu thp dliu.

Kin trc v qui m:

HTN qui m nh(Small Scale Embedded Systems) vi cc xc nh nh sau:

- Phn cng t phc tp, thit kvi CPU n, loi 4, 8 bits;

- Phn mm n gin, dng mt monitor kim sot hot ng;

- Cng c pht trin phn mm: son tho chng trnh, hp ng v hp ng cho(asembler, cross asembler), mi trng pht trin hp nht (integrated developememtenviroment) sdng vi vi iu khin hay CPU chn. Ngn ngpht trin l C,m C c dch ra nh phn ti u, nh v m thc thi trong b nh ROM, dunglng bnhgii hn.

- Tiu thnng lng rt t.V d: HTN n gin, chc mt vi phm bm a thng tin vo, mt vi n LED

hin u ra (trng thi no ). V d: HTN my iu ha nhit , l nhit v.v.

HTN qui m phc tp:

- Phn cng phc tp: Thit kvi CPU 8,16 hay32 bits, hay sdng vi iu khin;

- Hthng c cu trc vi BUS mrng ghp ni vi cc thit bngoi vi;

- Phn mm nhng tinh vi, c hiu hnh thc hin cc nhim v, thao tc ngthi. C thl loi RTOS.

-

Cng c lp trnh: C/C++/Visual C++/Java, RTOS, m ngun, cng c ki thut:Simulator, Debugger. Mi trng pht trin hp nht (Integrated DevelopmentEnvirinment-IDE. Cng csoft xy dng phn cng phc hp.

V d: cc HTN trn cc my gia cng (kim loi, khun nha v.v).

HTN tinh vi (Sophisticated Embedded Systems)

- Phn cng v phn mm rt c bit;

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- Nhiu CPU v c th m rng, hay cc CPU c th cu hnh c (configurableCPUs), hay mng logic lp trnh c (programable logic array-PLA);

- Pht trin cho cc lp ng dng mi nht khi cc ng dng loi ny cn phi 8cqu trnh thit kng thi gia phn cng v phn mm, hp nht cc linh kin hthng cui cng, sdng cng nghASIC chto CPU, vi mch ng xl (cngi l ChipSet hay Co-processor).

V d cc h thng hng khng qun s mi nht trn cc my bay (military/civilavionic ), cc thit bmng cao cp. Cc HTN kiu ny bchngbi tc xlca phn cng (CPUs), Cc chc nng phn mm nh cc gii thut m ha/gii m,gii thut chuyn i tn hiu s (Fourrier/Z transformation), giao thc TCP/IPstack, cc hm chc nng mng nhng trong phn cng tng tc x l; Mt schc nng phn mm c cng ha (nh DSP). Cng cpht trin thng khngc sn v t tin, do phi pht trin ring khi dn c chp nhn.

HTN phn cng hay HTN phn mm;

HTN theo An ton sc(fail-safe), hay tan ton (fail-safe operational);

HTN p ng c bo m hay p ng vi nlc ti a;

HTN vi ngun ti nguyn y hay ngun ti nguyn hn ch;

HTN phn ng ngay vi skin hay phn ng vi skin c thi hn.

Ti sao cc HTN li c skhc nhau ?

C thtrli n gin l do cc ng dng khc nhau v hthng phi hot ng hiu

qu. V d:1. HTN l dnh thc hin cc tc vring bit. Cc tc vring bit y phn ln

lin quan ti cc xl khc nhau chuyn bit, cc skin, cc trng thi ca mt quitrnh cng ngh, v dqui trnh iu khin my cng c, robot Khi thay i quitrnh, thng dn ti thay i hay thit kli chthng. Nh vy c ththy cn cmt loi bxl thch hp cho li tc v nu. Bxl nh vy gi l bxlchuyn bit (dedicated microprocessor), n khng mnh nh bx l a nng ta sdng trong my tnh, nh my tnh PC chng hn. V din hnh l bxl tn hiusDSP (Digital Signal Processor) dng TMS320 (TMS320C6000 Multicore DSPs,

TMS320DM6446 DaVinci Video Processor ) ca Texas Instruments, hay cc bxl MP3 (xl dliu m thanh nn v gii m a vo khuych i m thanhri ra loa).

V ds khi chc nng ca CPU DSP:

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Hnh 1.10 S khi CPU DSP-MP3.

Hnh 1.11 BMP3 vi CPU BlackFin ca ANALOG DEVICES

2. Nh im 1. nu trn, vphn cng, cc HTN c thit k t rt nhiu loi CPUnhng v cc CPU nhng bn thn chng li c kin trc khc nhau. Hin trn thtrng c th lit k cc kiu CPU nhng nh: CPU vn nng rt gn ph hp chong dng nhng, cc vi iu khin (microcontroller, PIC), cc kin trc kiu hthngtrn mt vi mch (PSoC-Programmable System on Chip)

3. Vphn mm csc thtn gin cho ti tinh xo, hiu hnh thi gian thc(RTOS-Real Time Operating System).

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4. V dmt sHTN

Phn cng thng mi l cc sn phm nh bo mch HTN (Microprocessor-based)y, thit khon chnh v i cng c phn mm hthng (hiu hnh, hay monitor)ci t trong EEPROM, flash, c RAM hay cn c a cng bn dn (DiskOnChip dunglng 32MB hay ln hn), v dnh dng PC 104 di y:

TMZ104

PC/104 Computer with Transmeta Crusoe TM5500 CPU

TMZ104 Photo Features:

Low power fanless x86 compatible

Embedded BIOS

Linux OSWatchdog timers

Dual EIDE & floppy support

USB, parallel port,

PS2 keyboard & Mouse

Dual RS-232 serial

Hnh 1.12 Mt sHTN thng mi

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Cc loi vi iu khin dng bo mch.

Cc loi vi xl ri thit kTHN theo yu cu ng dng:

CPU : Intel 80X51, PIC 12F 675, Amtel 8051, PSoC (Programmable System on Chip) :

CY8C29466 c im chung ca cc loi ny l c kin trc y chtrong mt vimch c mc tch hp cln v rt ln (VLSI: Very Large Scale Integration).

Bng di y lit k sloi CPU cho HTN tcc hng khc nhau (cha y ):

1.5 KT CHNG

Chng ny gii thiu vHTN tnh ngha, m hnh, phn loi, cc c th v kin trc caHTN. Chng cng nu ra nhng lnh vc cng nghm HTN c sdng. T cng bt ranhng yu cu kthut trn HTN ni chung v HTN cho ng dng ring bit.

Tham kho mt snh ngha HTN tcc ngun ti liu:

HTN l mt hthng c phn cng c xy dng trn nn tng phn cng my tnh chuynbit vi phn mm c nhng trong phn cng , nh mt trong cc thnh phn quan trngnht ca HTN. HTN do c thl mt hc lp hay l mt phn ca mt hthng ln hn.

Mt snh ngha vHTN:

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Wayne Wolf: what is an embedded computing system ? Loosly defined, it is any device thatincludes a programmable computer but is not itself intended to be general-purpose computer[Computers as ComponentsPrincipal of Embedded Computer System Design].

Told D. Morton: Embedded Systems are electronic systems that contain a microprocessor ormicrocontroller, but we do not think od them as computersthe computer is hidden or embeddedin the system [Embedded Microcontrollers]

Tim Wilmshurst: Embedded system is a system whose primcipal function is not computational,but which is controlled by a computer embedded within it. The computer is liklly to be amicroprocessor or micro controller. The word embedded implies that it lies inside the overalsystem, hidden from view, forming an integral part of greater whole [ An Introduction to theDesign of Small Scale Embedded System with PIC, 80c51 and 68HC05/08 Microcontroller]

1.6

CU HI CUI CHNG

1) nh ngha tng i vHTN.2) Nhng thch thc no phi i mt khi thit kmt HTN ?3) Nhng cch nu m hnh kin trc ca mt HTN ?4) Thno l HTN kiu vi xl HTN kiu vi iu khin ?5) Nu cc khi chc nng trong hnh 1.7 m tvm hnh mt HTN.6) C bao nhiu loi kin trc CPU c sdng khi xy dng HTN ? Mi loi khc

nhau im no chyu ?7) Nu cc thnh phn phn cng thng c trong mt HTN ?

8) Cc thnh phn nh bin i tng t-s (ADC), s-tng t (DAC), nh thi(timer), cng (port) nht thit cn c trn mt HTN ? Ti sao ?

9) C cc loi phn mm no trn mt HTN ?P

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Chng2. CC THNH PHN PHN CNG CA H THNG NHNG

Chng 2 cp ti cc thnh phn phn cng, nn tng c s ca HTN. Bao gm: bx ltrung tm (CPU) vi kin trc Von Neumman v kin trc Harvard, BUS ca CPU v BUS h

thng, bnh, cng. Tip theo l k thut ghp ni cc thit bngoi vi vo vi CPU, cc chngtrnh iu khin ghp ni. i vi CPU, ti liu nu nguyn l kin trc, cc c tnh k thut vbiu thi gian hot ng ca CPU, gip cho vic thit kphn cng sau ny. Ring vtp lnhkhng cp ti, do vy khi sdng mt CPU no cn nm c tp lnh ca CPU c

thlp trnh, vit cc trnh iu khn bng hp ng.

Ni dung chng cung cp cc kin thc phn cng v k nng thit k, c bit l thit kghpni vi thit b. Cui chng l mt sbi tp thit kn gin nh thit kbnhROM, RAM,

cng vi CPU, to thnh mt bo mch nh mt HTN cha c cc thit bngoi.

2.1

B X L TRUNG TM (Central Processing Unit-CPU)

Cc hthng sdng k thut tnh ton sxl thng tin u cn mt thp cc mch sto ra mt hthng c khnng: thc hin cc php tnh l lun l (logic), cc php ton shc,cc quyt nh chuyn hng thc hin c hay khng c iu kin v quan trng l hot ngtheo mt hm vi lnh (micro-instruction code) theo mt trnh tnht nh. tng to ra mththng in tsnh vy chnh l to ra mt bxl trung tm. Bxl trung tm ngy nayrt tinh xo, kch thc rt nh ( chln hn 1 cm ) nhng cha vi trm triu transistor, hotng vi tn stvi MHz ti vi GHz, cng sut tiu tn tvi Watt ti vi chc Watt , v d:Intel Pentium G6950 cng ngh: Clarkdale (32 nm), tn

s:2.8 GHz,Powerdissipation:73W.(http://en.wikipedia.org/wiki/List_of_CPU_power_dissipation#Intel_Pentium_Dual-Core). i li tc tnh ton t hn 1 tlnh my trong mt giy (MIPS:milions Instruction per second). V d:Intel Core i7 Extreme Edition i980EE:147.600 MIPS at3,3 GHz , 44.7 lnhmy/chu kxung ng h(vi f=3,3GHz, Tchuk=0,303 ns).(http://en.wikipedia.org/wiki/Instructions_per_second).

y l ni ti cc bxl vn nng, dng chto cc my tnh (bn, my ch). i vicc CPU dng trong thit kcc HTN, tn s lm vic ca CPU c thp hn, tvi chc, vitrmMHz tr ln. Ti sao vy ? n gin khng phi lc no cng cn tc tnh ton thtnhanh, v cn ty vo ng dng nhng l g. Tt nhin cng nhanh cng tt, nhng i li gi

thnh cao, mi trng hot ng khng ththa mn (v dnhit mi trng cao, bi, rungng c hc ).

2.2.1 Cc loi CPU v nguyn l hot ng

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Hin nay trn thtrng rt nhiu nh sn xut CPU vi nhiu chng loi ph hp cho cc ngdng. C thlit k mt snt phn bit:

a) Cch tchc v thc hin lnh my:

- Vi tp lnh y (CICS).

- Vi tp lnh rt gn (RISC).b) Cch xl thng tin v truy nhp bnh:

- Von Neumman: bnhchung, truy cp tun ttheo tng lnh my.

- Harvard: bnhlnh v bnhdliu c lp, truy cp ng thi.

c) Cng nghchto hng ng dng:

CPU a nng: chto my tnh a nng, HTN tinh vi, hiu khin thng minh. CPU chuyn dng: cc ng dng c th ( nh cho ng dng nhng). Trong phm

tr ny li c mt vi cng nghtiu biu:- Vi iu khin (microcontroller v PIC-Programmable Intelligent Computer"

(My tnh khtrnh thng minh)).- Hthng trong mt vi mch lp trnh c (PSoC-Programmable System on

Chip: integrating configurable analog and digital peripheral functions,

memory and a microcontroller on a single chip).

Lp cng nghny c sdng phbin trong cc HTN c i hi mc tinh xotrung bnh hay thp.

2.2.2 V dvmt CPU v nguyn l hot ng

c ththc hin thit kmt HTN, cn tm hiu chi tit vcu trc, cch lm vic v lp trnhcho mt CPU chn. Phn ny gii thiu dng Intel CPU 808X, 8 bits hay 16 bits, a nng

ca Intel c sdng rt phbin trn thgii cng nh Vit Nam. u im ni bt ca CPUny l tnh phbin, a nng, dtrin khai, cng cpht trin rt a dng v sn c.

a) S hnh thc bn ngoi:

Hnh 2.1 Intel CPU 8085

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b) Kin trc: M hnh chc nng bn trong CPU, v dIntel 8080/80858085 l 8-bit microprocessor, trong dliu xl l 8 bits, khng gian a chc xc nhbi 16 bits, cho dung lng a chl 65.535 (gi l 64K) nh. Cc thnh phn chc nng baogm:

Tp cc thanh ghi (Register). n vthc thi cc php tnh shc v lun l (Arithmetic logic unit- ALU). Hthng cc dy ni gia cc vi mch chc nng( BUS). Khi nh thi v iu khin (Timing & Control unit). Khi iu phi, kim sot ngt (Interrupt Control) Khi truyn thng ni tip (Serial I/O Control)


1) Tp cc thanh ghi (Registers):Cc thanh ghi sdng cha dliu v a ch. Co hai loi thanh ghi:

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Thanh ghi a nng c dng nh chc nng nhdliu tm thi hay chtc thi qui chiuti bnh(ROM/RAM). Cc thanh ghi 8 bits l B, C, D, E, H v L. Khi ghp li sthnhthanh ghi 16 bits vi tn kp: BC, DE or HL.Thanh ghi c bit l cc thanh ghi gn cho chc nng c bit (hay chuyn dng):

Thanh ghi tch lyACC (Accumulator)hay A, l thanh ghi 8-bit, a dng cho cc thaotc v cc php tnh s hc, lun l, I/O, np, nh d liu, ton hng, kt qu php tonkhi thc hin lnh.

Thanh ghi chs(Index register): c dng lm chscho qui chiu a ch, cchdng phthuc vo cha chha.

Thanh ghi a nng (General registers) 16 bit chia phn thp v phn cao:

8-bit B v 8-bit C hay kt hp thnh cp BC 16-bit.

8-bit D v 8-bit E hay kt hp thnh cp DE 16-bit.

8-bit H v 8-bit L hay kt hp thnh cp HL 16-bit.

Cc thanh ghi ny dng c lp hay kt hp cha dliu hay a chqui chiu vo bnh(chda chha gin tip qua thanh ghi).

Thanh ghi trng thi(Status register) hay C (Flag), l thanh ghi 8-bit, cha cc bit c ngha sau:

Sign, ln 1 nu bit ln nht ca kt quphp tnh c gi tr= 1.

Zero, lp gi tr= 0, nu kt quphp tnh = 0.

Auxiliary carry, vi php tnh 4 bit (D3-D0), ln 1 nu kt quphp tnh c smangtD4 chuyn sang D4.

Parity, ln 1 nu sparity (l tng ca cc bit trong kt qu) l schn.

Carry, ln 1 nu c s mang khi thc hin php cng shc hay borrow khi thchin php trshc hay php so snh gi tr.

Thanh ghi ngn xp(Stack pointer): 16 bit. Thanh ghi ny mi ln tng hay gim 2 (+/-2).

Thanh ghi lnh my(Instruction register): 8 bit cha m lnh (OPCODE) tROM/RAM, u vo cho khi Timing&Control gii m thnh cc tn hiu iu khinca CPU.

Thanh m chng trnh (Program counter), 16-bit, tr trc tip vo b nh ni cham lnh ca mi lnh.a ch qui chiu t 0000h n FFFFh (0 n 65.535).

2)n vthc thi cc php tnh shc v lun l(ALU):Thc hin cc php tnh: Cng, tr, nhn, chia, logis AND, OR, XOR, NOT, dch tri/phi, quayvng tri/phi.3)Hthng cc dy ni gia CPU vi cc vi mch chc nng, thit bngoi(BUS) (Hnh1.1.1- M hnh tng qut bo mch ch)Tp hp cc tn hiu pht ra tCPU v ni ti cc vi mch chc nng trn bo mch chnh. mt ngha ca tng tn hiu ta nhm li theo chc nng nh sau:

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BUS a ch(Address bus): Mang thng tin vda chqui chiu ti ROM/RAM, bgii mchn vi mch. Vi CPU 8080/8085 c tt c16 ng hay 16 bit. BUS ny chc mt hng(chiu) i ra tCPU.BUS dliu(Data bus) : Dliu trao i gia CPU v cc vi mch bn ngoi, cc thit b

ngoi sdng BUS ny. Ty loi CPU c thl 8 bit, 16 bit, 32 bit, 64 bit. Sbit ny thngdng ni ti loi CPU. c im c bn ca BUS l hai chiu.BUS iu khin(Control bus): Cc tn hiu iu khin pht ra tCPU ti cc vi mch chcnng khc nhau trn bo mch ch, cc thit bngoi ni vi CPU. Cc tn hiu ny cdng ng bmi bc hot ng ca my tnh.

4) nh thi v iu khinKhi ny to ra tt ccc tn hiu ng h, cc tn hiu iu khin bn trong CPU, CPU vi bnngoi qua Bus iu khin (Control bus).c)Bnh(Memory)Chng trnh ng dng, h iu hnh, d liu, ngn xp u dng chung khng gian nh. Vi h8080/8085 c 16 dy a ch (A15 ... A0) cho dung lng nh ti a l 65.535 a ch nh.Nu mi nh l 1byte s c 65.535 byte hay 64 KB.Kin trc s dng 64 bytes u tin (000F-0000) t cc vector ngt ca cc lnh RST. d)Ngt (Interrupts)CPU 8085 c 5 u vo tn hiu ngt (interrupt), trnh by theo th t u tin t thp n cao:

INTR,che c. Khi c ngt xut hin, CPU s tm lnh trn BUS, lnh c th l trong cclnh RESTART (u c hiu lc khi ng li CPU) loi RST (RST 5.5, RST 6.5, RST 7.5 v

TRAP). CPU bo lu gi tr ca PC vo ngn xp, chuyn ti nh c gi tr N*8, trong N cgi tr t 0 n 7 m lnh RST cung cp. nh ny cha a ch ca chng trnh x l cho ngt nh sau:

Tn ca ngt a ch chng trnh khi ng ti:

TRAP 24 Hex

RST 5.5 2C Hex

RST 6.5 34 Hex

RST 7.5 3C Hex (u tin cao nht, tc dng sn ln ca xung ngt)

Lnh gi CALL (lnh c 3 byte ). CPU gi mt chu trnh con c a chxc nh byte th2

v th3 ca lnh ny.

RST5.5, che c. Khi c ngt ny, CPU bo lu gi trca PC vo ngn xp, nhy ti achcnh 002Ch (h-hexadecimal).

RST6.5, che c. Khi c ngt ny, CPU bo lu gi tr ca PC vo ngn xp, nhy ti ach c nh 0034h.

RST7.5che c. Khi c ngt ny, CPU bo lu gi tr ca PC vo ngn xp, nhy ti ach c nh 003Ch.

Trap, khng che. Khi c ngt ny, CPU bo lu gi tr ca PC vo ngn xp, nhy ti ach c nh 0024h.

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Tt c cc ngt che c c th lp khng che hay che lp trnh qua lnh EI v DI. RST 5.5,RST6.5 v RST7.5 lp trnh bng lnh SIM.

e) Cng vo/ra (I/O ports)H8080/8085 c tt c256 cng vo v ra, 256 cng ra chy theo lnh IN hay OUT.f)

Tp lnh (Instruction Set)Tp lnh ca CPU Intel 8085 gm cc nhm sau y:

- Lnh chuyn dliu.

- Lnh shccng, tr, tng, gim.

- Logic - AND, OR, XOR v quay vng.

- Chuyn iu khin i c/khng iu kin, gi chu trnh, trvchc khi thot khi chu

trnh, khi ng li.

- Lnh vo/ra (I/O).

- Cc lnh thao tc bit, c, cho php/khng cho php ngt, ngn xp,

g)

Cha ch(Addressing modes)

- Kiu thanh ghi:qui chiu d liu trong 1 thanh ghi hay i thanh ghi.

- Gin tip qua thanh ghi:Thanh ghi cha a ch nh ni c d liu.

Qui chiu trc tipD liu 8 hay 16 bit.

i) Cc nhm tn hiu trong CPU 8080/8085

A8A15.Nhm tn hiu ra: 8 bit cao ca a ch, cc chn ny l cc chn c ni vi bnngoi qua mch 3 trng thi. Cc phn t 3 trng thi s c t trng thi trng thi tr

khng cao (cn gi l trng thi khng kt ni) trong cc trng hp mt trong cc tn hiuHOLD hay HALT l tch cc.

AD0AD7.Nhm tn hiu dn knh cho cc tn hiu a ch v tn hiu d liu theo chia sthi gian, 3 trng thi. giai on u ca chu k my, T1 ca M1, s l byte thp ca 16 bita ch t A0 n A7.

ALE (Address Latch Enable). Tn hiu ra qua mch 3 trng thi. c s dng cht bytethp ca tn hiu a ch (A0 A7) t nhm AD0-AD7. Tn hiu ny c to ra trong giaion u tin ca chu k my, T1 ca M1, v cng c dng cht cc tn hiu trng thiS0 v S1 khi cn thit.

S0, S1 (Data BUS Status). L cc tn hiu ch trng thi ca cc chn thuc BUS d liutrong mi chu k my. T hp ca hai tn hiu ny cng cho bit trng thi ca CPU nh sau:

S1 S0 Trng thi hot ng ca BUS d liu0 0 Trng thi HALT

0 1 CPU ang thc hin thao tc WRITE

1 0 CPU ang thc hin thao tc c (READ)

1 1 CPU ang thc hin thao tc nhn lnh (Instruction Fetch)

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RD (Read). Chn ra 3 trng thi. Nm trong nhm tn hiu iu khin. Tn hiu tch cc khiCPU tin hnh c d liu tb nh hoc t thit b ngoi vi. Trong ch HALT hocDMA, chn ra ny trng thi trng thi tr khng cao.

WR (Write). Chn ra 3 trng thi. Nm trong nhm tn hiu iu khin. Tn hiu tch cc khi

CPU tin hnh ghi d liu vo b nh hoc a d liu ra thit b ngoi vi. Trong cc ch HALT hoc DMA, chn ra ny trng thi trng thi tr khng cao.

IO/M. Trng thi logic ca u ra ny cho bit CPU ang lm vic vi thit b ngoi vi hayvi b nh. Nu l logic 1, CPU ang truy cp thit b vo/ra, cn nu l 0, CPU ang truycp b nh. Kt hp vi hai u ra RD v WR to ra cc tn hiu I/OR, I/OW, MEMR, vMEMW trong trng hp s dng a ch tch bit i vi thit b vo/ra. Nm trong nhmtn hiu iu khin, IO/M cng l u ra 3 trng thi.

Interrupts. P8085 c ngt a mc. C 5 chn ngt tt c: (INTR, RST5.5, RST6.5, RST7.5v TRAP). Ngoi chn ngt khng che c l TRAP, cc chn khc u c th che hoc

khng che nh lp trnh phn mm. INTR: Chn nhn yu cu ngt tbn ngoi, c p ng theo nguyn tc quay vng(polling) hoc vector thng qua lnh RST

Cc yu cu ngt RST: C 3 u vo yu cu ngt vi cc mc u tin khc nhau lRST7.5, RST6.5 v RST5.5. Khi yu cu ngt xut hin ti cc chn ny, CPU t ngchuyn n cc vector ngt tng ng. Cthnh sau:

- RST5.5 l mc u tin thp nht, phn ng theo mc in p trn chn yu cu ngt,a chvector ngt ny nm nhc a ch2CH.

- RST6.5:Ngt u tin thp th2, phn ng theo mc in p trn chn yu cu ngt,

a chvector ngt ny nm nh34H- RST7.5: Mc u tin cao nht. Phn ng theo sn ln ca xung yu cu ngt. Sn

ln ca xung ny tc ng ln mt Flip-Flop, mch ny gili yu cu ngt cho nkhi c xo nhtn hiu p ng nhn bit yu cu ngt (Acknowledge). a chcavector ngt ny nm nh3CH

TRAP: L chn nhn yu cu ngt khng che c (d nhin l n c mc u tin cao nh t).a chca vector ngt ny nh24H.

INTA. Tn hiu ra nhn bit yu cu ngt ti chn INTR. Cc yu cu ngt RST5.5, RST6.5,RST7.5 v TRAP khng tc ng n INTA.

HOLD. Trng thi logic 1 chn ny l yu cu ca thao tc DMA. Cc u ra RD, WR,IO/M v ALE sc a vtrng thi trkhng ra cao.HLDA. Tn hiu nhn bit yu cu HOLD.RESET IN. Logic thp 0 u vo ca chn ny yu cu ti khi ng hvi xl. Do tcng ca tn hiu RESET IN tch cc, gi trca thanh m chng trnh PC sc np lil 0000h. Cc mt nngt v tn hiu HLDA cng c ti thit lp vgi trmc nh.RESET OUT. u ra nhn bit hvi xl c ti khi ng. Dng tn hiu ny ti khing ton bhthng.

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READY. Logic 1 u vo ny thng bo trng thi sn sng cung cp d liu choCPU hoc nhn dliu tCPU ca cc thit bngoi vi.SID (Serial Input Data). L cng vo ca dliu ni tip ca hVi x l. Bit hindin ti cng ny c c vo CPU nh lnh RIM, bit sc a vo bit cao ca Acc

(MSB).SOD (Serial Output Data). Bit cao (MSB) ca Acc c truyn ra ngoi chn ny khi sdng lnh SIM.X1, X2. Li ni thch anh hoc mt mch dao ng to xung nhp cho CPU. C thsdng thch anh c tn sdao ng trong khong t0.5 n 3MHz.CLK. u ra ca xung nhp, c thlm xung nhp cho cc thnh phn chc nng khc tronghvi xl.Vcc, Vss. Li ni ngun +5V v GND cho CPU 8085. Cng cn nhc li rng, CPU 8085 chcn mt ngun nui duy nht l +5V, khnng cung cp dng ca ngun cn c thit k

tutheo nhu cu ca ton hvi xl.j)Biu thi gian (system timing)Khi thit k phn cng ca mt HTN ni ring hay mt thit b k thut s ni chung, khinim v biu thi gian l ht sc quan trng. Nm bt c ngha ca biu thi gians c ch khi tin hnh hiu chnh v tm li phn cng. Li phn cng thng xy ra khi cctn hiu hot ng khng ng thi im u vo mch s, gy ra li, t bit hay xy ra cc mch t hp. Di y l mt s nh ngha cc b x l:

Trng thi my: T (machine State): c nh ngha l thi gian ca mt chu k xungng h h thng (CPU Clock-out). V du nu Clock-out=10 Mhz, th T=200ns. Ccsn xung ln/xung c s dng bn trong CPU cho cc thao tc khc nhau.

Chu k my (hay chu k BUS): M (machine cycle): L tp hp ca mt s cc T

CPU hay mt vi mch ( nh DMAC 8237) khi nm quyn kim sot BUS h thng,thc hin xong mt thao tc (mt phn ca qu trnh gi ra hay c vo mt d liu)trn BUS h thng.

Chu k lnh: (Instrution cycle): l tp cc M cn thit hon thnh mt lnh my.

Hnh sau y m t thc thi ca lnh STA cua CPU Intel 8085: Ct ni dung trongthanh ghi ACC ca CPU v nh tr trc tip bi 2 byte tip theo ca lnh: ([byte 3],

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Chu k lnh

M1 M2 M3 M4

T1 T2T2 T3 T4 T1 T3 T1 T2 T3 T1 T2 T3

CPU Clock-CLK

Kiu chu ki my

BUS a ch

BUS D liu

c b nh c b nh c b nh Ghi b nh

PC tr ti byte u tin l mlnh (OPCODE) ca lnh

OPCODE

PC=PC+1, tr tibute th 2 ca lnh

Byte thp ca ach trc tip

PC=PC+2, tr tibyte th 3 ca lnh

Byte cao ca ach trc tip

Pht a ch ly M2 va M3 tr ti b

nhGhi ni dung ca

ACC vo nh

V d thc hin lnh c di 3 byte, ct ni dung ca ACC vo nh tr bi ach trong lnh: STA [ a-ch-thp, a-ch-cao]

Mi: Chu k my , Ti: trng thi my

Hnh 2.3 Cc khi nin qui chiu theo CPU Clock

Ta c th theo di cc xung in ny khi s dng my hin sng (OSCILOSCOPE) vi t nht 2tia cp vo v tr thch hp trn bo mch, ly xung ng h CPU CLK lm chun ng b cc

tn hiu.

Vic thc hin mt lnh trong CPU P8085 thc t l mt chui cc thao tc READ v WRITE.Mi thao tc READ hay WRITE tng ng vi mt chu k my M. Mi lnh c thc hin qua1 n 5 chu k my. Mi chu k my cn t 3 n 5 nhp ng h. V d lnh STA ni trn c 5chu k my, 13 trng thi my.

Sau y l m thot ng ca CPU 8085 vi cc chu k ng hhthng v cc thao tc khc.chu kmy thnht, CPU thc hin np m lnh (Instruction Code Fetch) trong RAM, cngi l chu kOpcode Fetch. Hnh di cho thy rng vic thc hin chu kmy M1 (OpcodeFetch), CPU gi ra cc tn hiu IO/M, S1 v S0 (tng ng 0, 1, 1 trn biu thi gian) xcnh thao tc ca chu k.

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Hnh 2.4Lu thi gian c sca CPU 8085 (Theo ti liu ca hng Intel)

CPU cng ng thi gi 16 bit a chra chu kmy u tin, ngay tnhp u tin (T1) xc nh nhhay thit bI/O. Phn a chbyte thp t trn AD7-AD0 (Program Counter Lowbyte-PCL) chtn ti trong thi gian 1 nhp nn cn phi c cht li nhtn hiu ALE mccao. Cn phn a chbyte cao t trn A16-A8.

Khi D7D0 n nh trn cc dy dliu, CPU gi tn hiu RD. Khi nhn c dliu,

RD chuyn ln mc cao cm vtr nhhay thit bI/O.

Slng chu kmy v trng thi cn cho thc hin mt lnh l cnh, song slng ny khcnhau i vi cc lnh khc nhau, tutheo di ca tlnh (1 byte, 2 bytes, 3 bytes). Slngchu kmy phthuc vo sln CPU phi lin lc vi cc phn tkhc trong hthng, chyul vi cc chip khc.

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Hnh 2.5 Biu thi gian ca chu k tm lnh.

2.2CPU 8085 V H THNG BUS

Vic u tin trong thit kmt HTN l la chn CPU v hnh thnh BUS hthng trc khi m

rng vi cc thnh phn khc nh ROM, RAM v cc cng ghp ni. Tip tc vi t duy sdnghIntel 808X, ta sthit khthng BUS nh sau:

c im ca cc chn/tn hiu pht ra tCPU: Nh trn lit k, CPU a ra 3 tp hp tnhiu chnh, bao gm:

- Tp tn hiu a ch trn cc chn AD7 AD0 v A8 A15, trong AD7 AD0 l ccchn 2 chc nng : Lc (M1, T1) l a chphn thp, sau l d liu. Do to ra 16ng a chta cn cht cc gi trny li vi htrca tn hiu ALE (Address Latch Enable)vi vi mch SN74373. Tp hp ny to thnh BUS a ch.

- Tp cc chn dliu AD7AD0 cc chu ki M/T tip theo ca chu k lnh. Tp hp ny to

thnh BUS d liu. BUS d liu c rng khc nhau theo loi CPU, c th l 4, 8, 16, 32, 64,hay trn mt loi BUS c bit chung ghp ni vo vi mch ng x l (ChipSet), gi l BUSpha trc (Front Side Bus-FSB) cc mt PC hin i, rng co th ln 128, 256 hat 1024 bit.

- Tp cc tn hiu iu khin pht ra t CPU, l BUS iu khin.

- Do cn ghp ni vi cc thit b bn ngoi, cn mt BUS khc gi l BUS h thng mrng, v du: ISA, EISA, v ph bin l PCI. Cc BUS ny cn c nh ngha tng minh v

c giao thc hot ng rt phc tp.

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ng h thchanh nhp chun

Ngun nui mtchiu

D7

D0

A8

A15

A0

A7

A15

A8

ALE

AD0

AD7

STB

A7

A0

L

a

t

c

h

RD/

WR

IO/M

INTA

Address BUS

DATA BUS

Control BUS

CPU 8085

Hnh 2.6 Cu hnh ti thiu: CPU 8085 v to BUS hthng

Do chc nng ca BUS l truyn thng tin gia cc thnh phn hp thnh ca my tnh v do c vai tr rt quan trng nh hng ti hiu nng ca my tnh, nn i khi phi xem xt timt khi nim v thng lng ca BUS (nh bt k loi thit b truyn thng tin no). l gitr v lng d liu ti a c chuyn qua BUS trong mt khon thi gian no , thng thngqui theo CPU clock (hay chu k lnh):

Tc truyn ti a =Tc BUS MH) x s byte mt ln truyn

S chu k Clock cho mt ln truyn

2.2.1 Khi nim v bn cht vt l ca cc BUS

Hot ng ca mt h k thut s thc cht l vic trao i v x l cc gi tr nh phn gia ccthnh phn, cc khi v cc mch vi in t trong ton b h thng. Nh bit, cc gi tr nhphn (hoc 0 hoc 1) c th hin qua mc in p so vi mt chun nht nh, v d chun

TTL (transistor-transistor logic) gi tr 0 tng ng vi mc in p thp (t 0V n +0,8V) vgi tr 1 tng ng vi mc in p t khong +3V n +5V. biu din mt s liu nh phn,cc phn t mang thng tin c lin kt k nhau theo nhm (v d 1byte l 8bits). m nhn

cng vic di chuyn cc d liu ny trong ton b h thng, c cc ng dy truyn dn in

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c ghp song song thnh h thng, mi dy truyn dn dnh ring cho 1 bit. Tp cc ngtruyn dn dnh ring cho cc tn hiu c cng chc nng (d liu, a ch, iu khin v trng s

(2n)) c gi l BUS. BUS gii quyt mt vn k thut c s quan trng l: ni c hai u

ra ca hai mch in t khc nhau m khng lm cho u ra no b hng. Yu t c bn y l

cc u ra phi c iu khin bng chng trnh my tnh a u ra ca vi mch vo mttrong hai ch lm vic c bit (hay gi l trng thi) sau: hot ng bnh thng, ti nnglng ln dy kt ni v trng thi khng hot ng v c tr khng u ra cao ( Tri-state) khng on mch u ra ca vi mch kia. Lm c nh vy tn hiu s i c c hai chiu trncng mt dy ni. V h qu l gim i mt na cc chn ni ra/vo ca vi mch s.

Nh vy, trong mt h my tnh BUS c mt s tiu ch sau y:- BUS phi tun theo 1 chun no . Tp cc quy tc ca chun cn c gi l giao thc bus (bus

protocol)

- C thc nhiu loi bus khc nhau c sdng, cc bus ny ni chung l khng tng thch vi

nhau.- Bus thng phn loi theo 3 cch sau:

Theo tchc phn cng Theo giao thc truyn thng ( bus ng bv khng ng b) Theo loi tn hiu truyn trn bus :

BUS d liu, l BUS hai chiu, c trng thi tr khng cao.

BUS a ch: l BUS mt chiu v thng thng a ch pht sinh ra tCPU. Tuy nhin phi c kh nng trng thi tr khng cao khi cn thit.

BUS iu khin, cc tn hiu iu khin t CPU hay vi mch chc nngkhc..

Cc BUS ny hp li thnh BUS ca CPU. BUS ca CPU thng c ti u ra yu, nn BUS ny c khuych i,

cn c CPU Clock_out (hay BUS Clock) to thnh BUS h thng. Skhc nhau l ch:

BUS ca CPU:

i ra trc tip t CPU

BUS dn knh

BUS h thng:

Khng ni trc tip voCPU, m qua khuych iBUS

Khng cn dn knh, cc

BUS tch bit Ph ti ln hn

C BUS Clock trn BUS

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Hnh 2.7 CPU Bus v BUS h thng

T khi nim trn, d dng suy ra bn cht vt l ca cc BUS trong mt h my tnh: l ccng truyn dn in, c th di cc dng cp nhiu si, ng dn trong cc bng mch inv.v Kh nng v cht lng dn in ca cc ng truyn dn ny ng vai tr quan trng vquyt nh i vi hot ng ca mt h my tnh. ng truyn dn km, in tr thun cao c

th gy ra s suy gim ca tn hiu in dn n cc hin tng mt hoc sai d liu. BUS lng dn in ni b m theo cc tn hiu c truyn t b phn ny n cc b phn khc

trong h my tnh.

2.2.2 Khuych i BUS (bus driver)

Tn hiu pht sinh tCPU thng c cng sut thp chcho mt sti danh nh (fan-out), khng mrng BUS, nht l khi bus kh di v c nhiu thit bni vi n. Chnh v thm hu ht cc BUS

c ni mt svi mch khuych bus (bus driver), vc bn l cc vi mch khuych i tn hiu s.Hu ht vi mch khc ni vi BUS qua vi mch u vo (bus receiver). i vi cc thit bkhi th ngvai tr a tn hiu ln BUS (master), khi th ng vai tr nhn tn hiu tBUS (slave), ngi ta sdngmt vi mch kt hp c khnng pht ra v nhn v, gi l vi mch pht v thu tn hiu (bustransceiver).Cc chip ny ng vai tr ghp ni v l thit b3 trng thi, cho php n c thtrng thi th3 tr

khng cao. Cc vn quan trng nht lin quan n thit kbus l: xung ng hbus (clock bus: sphn chia theo thi gian, hay cn gi l bus blocking), c chtrng ti bus (bus arbitration), xl ngt vxl li. Cc bus c thc chia theo giao thc truyn thng thnh hai loi ring bit l bus ng bv

bus khng ng bphthuc vo vic sdng clock bus.

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2.2.3 Bus ng b (Synchronous bus):

Bus ng bc mt tn hiu trn ng dyBUS clockdng sng vung, vi tn sv d, trongkhong vi MHz GHz. Mi hot ng bus xy ra u qui chiu vo BUS Clock, trong mt snguynln chu kny v c gi l chu kbus. Hnh sau gin thi gian ca mt bus ng bvi tn sxung

BUS clock l 4MHz, nh vy chu kbus l 250ns. Gisc 1 byte tbnhchim 3 chu kbus (750ns), tng ng vi T1, T2, T3 nh hnh v. V tt ccc bng bn dn khi chuyn mc khng phi l tcthi, m c qu v mt mt khon thi gian, nn trn hnh vc cc sn xung, ta giscc snxung ko di 10ns. Con sny rt quan trng khi thit kmch k thut s!

Hnh2.8 Chu k c ng b

T1bt u bng cnh dng ca xung clock, trong mt phn thi gian ca T1, vi xl t a chbytecn c ln bus a ch. Sau khi tn hiu a chc xc lp, vi xl t cc tn hiu MREQ v RD tchcc mc thp, tn hiu MREQ (Memory Request) - xc nh truy xut bnhchkhng phi thit bI/O,cn tn hiu RD - chn c chkhng phi ghi dliu.

T2: thi gian cn thit bnhgii m a chv a dliu ln bus dliu.

T3: ti cnh m ca T3, vi xl nhn dliu trn bus dliu, cha vo thanh ghi bn trong vi xl vcht dliu. Sau vi xl o cc tn hiu MREQ v RD. Nh vy thao tc c hon thnh, ti chukmy tip theo vi xl c ththc hin thao tc khc. Cc gi trcthvthi gian ca hnh vtrn c

thc gii thch chi tit nh sau:TAD: TAD


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ca T2. Thao tc ny a thm cc trng thi chwait state (tc l a thm vo 1 chu kbus), khi bnh a ra tn hiu n nh, n so WAIT thnh WAIT

TML: m bo tn hiu a chsc xc lp trc tn hiu MREQ t nht 60ns. Khong thi gian nysquan trng nu tn hiu MREQ iu khin qu trnh to tn hiu chon chip CS hay CE do mt schipnhi hi phi nhn c tn hiu a chtrc tn hiu chn chip. Nh vy, khng thchn chip nhvi thi gian thit lp 75ns.

TM, TRLcho php hai tn hiu MREQ v RD tch cc trong khong thi gian 85ns tnh tthi imxung ca xung clock T1. Trong trng hp xu nht, chp nhchc 250 + 250 85 50 = 365ns saukhi 2 tn hiu trn tch cc a dliu ra bus dliu. Sbt buc vthi gian ny bsung thm sbtbuc thi gian vi tn hiu clock.

TMH, TRH: thi gian cc tn hiu MREQ v RD c o sau khi dliu c vi xl nhn vo.

TDH:Thi gian bnhcn gidliu trn bus sau khi tn hiu RD o.

Gin thi gian mt chu kc trn bus ng b c n gin ho

so vi thc t, trong cc tn hiu cn sdng ln hn nhiu. Gi trti

hn ca cc thng scho trong bng sau:

K hiu Tham s Min (ns) Max (ns)

TAD Thi gian trca a ch 100

TML Thi gian a chn nh trc MREQ 60

TM Thi gian trca MREQ so vi cnh m

ca T1

85

TRL Thi gian trca RD b so sn xungca tn hiu ng bT1

85

TDS Thi gian thit lp dliu trc snxung ca tn hiu xung clock( tn hiu

ng h)

50

TMH Thi gian trca MREQ b so vi sn

xung ca tn hiu ng hT3

85

TRH Thi gian trca RD b so vi snxung ca tn hiu ng hT3

85

TDH Thi gian lu trdliu tlc o tn

hiu RD

0

Truyn theo khi:

Ngoi cc chu kc/ghi, mt sbus truyn dliu ng bcn htrtruyn dliu theo khi. Khi btu thao tc c khi, vi mch lm chbus (bus master) bo cho vi mch khc (slave) bit sbyte cnc truyn i, th dtruyn con sny i trong chu kT1, sau ng ltruyn i 1 byte, slave a ra

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trong mi chu k1 byte cho ti khi sbyte c thng bo. Nh vy, khi c dliu theo khi, n bytedliu cn n+2 chu kclock chkhng phi 3n chu k.

Mt cch khc cho truyn dliu nhanh hn l gim chu k. v dtrn: 1 byte c truyni trong 750ns, vy bus c tc truyn 1.33MBps. Nu xung clock c tn s8MHz, thi gian 1 chu kchcn mt na, tc sl 2.67MBps. Tuy nhin, gim chu kbus dn n kh khn vmt kthut,cc tn hiu truyn trn cc ng khc nhau khng phi lun c cng tc , dn n hiu ng mo dngtn hiu. iu quan trng l thi gian chu kphi di hn so vi stn ti ca mo dng tn hiu trnhvic nhng khong thi gian c sho li trthnh cc i lng bin thin lin tc.

2.2.4 Bus khng ng b (Asynchronous bus)

Bus khng ng bkhng sdng xung BUS clock, chu kca n c thko di tu v c thkhcnhau i vi cc cp thit bkhc nhau, gi l i thoi tun tbi cc tn hiu iu khin. Lm vic vicc bus ng bddng hn do n c nh thi mt cch gin on , tuy vy chnh c im ny cngdn n nhc im. Mi cng vic c tin hnh trong khong thi gian l bi sca xung clock, nu

1 thao tc no ca vi xl hay bnhhon thnh trong 3,1 chu kth n cng sphi ko di trong 4chu k. Khi chn chu kbus v xy dng bnh, I/O card cho bus ny th kh c th tn dngnhng tin bca cng ngh. Chng hn sau khi xy dng bus vi snh thi nh trn, cng nghmi a ra cc vi xl v bnhc thi gian chu kl 100ns chkhng cn l 750ns nh c, th chngvn chy vi tc thp nh cc vi xl, bnhloi c, bi v giao thc bus i hi bnhphi ac dliu ra v n nh trc thi im cnh m ca T3. Nu c nhiu thit bkhc nhau cng ni vi1 bus, trong c thc mt sthit bhot ng nhanh hn hn cc thit bkhc th cn phi t bushot ng ph hp vi thit bc tc thp nht. Bus khng ng bra i nhm khc phc nhngnhc im ca bus ng b.

Hnh 2.9 BUS khng ng b, hot ng ng b bi i thoi giacc tn hiu iu khin.

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Trc ht master pht ra a chnhm n mun truy cp, sau pht tn hiu MREQ b tch cc xcnh cn truy xut bnh. Tn hiu ny cn thit khi bnhv cc cng I/O sdng chung min a ch.

Sau khi pht a ch, bn master cng phi pht tn hiu RD tch cc bn slave bit rng master sthchin thao tc c chkhng phi ghi. Cc tnh hiu MREQ b v RD b c a ra sau tn hiu a chmt khong thi gian phthuc tc hot ng ca master. Sau khi 2 tn hiu ny n nh, master spht ra tnh hiu MSYN (master synchrization) mc tch cc bo cho slave bit rng cc tn hiu cnthit sn sng trn bus, slave c thnhn ly. Khi slave nhn c tn hiu ny, n sthc hin cngvic vi tc nhanh nht c thc, a d liu ca nhc yu cu ln bus d liu. Khi honthnh slave spht tn hiu SSYN (slave synchronization) tch cc. Master nhn c tn hiu SSYN tchcc th xc nh c dliu ca slave sn sng nn thc hin vic cht dliu, sau o cc ng

a chcng nh cc tn hiu MREQ, RD, v SSYN. Khi slave nhn c tn hiu MSYN khng tch cc,n xc nh kt thc chu kv o tn hiu SSYN lm bus tr li trng thi ban u, mi tn hiu ukhng tch cc, chbus master mi. Trn gin thi gian ca bus bt ng b, ta sdng mi tn thhin nguyn nhn v kt quMSYN tch cc dn n vic truyn dliu ra bus dliu v ng thicng dn n vic slave pht ra tn hiu SSYN tch cc, n lt mnh tn hiu SSYN li gy ra so

mc ca cc ng a ch, MREQ b, RD b, v SSYN. Cui cng so mc ca MSYN li gy ra so mc tn hiu SSYN v kt thc chu k. Tp cc tn hiu iu khin phi hp vi nhau nh vy cgi l kt ni hon ton (full handshake), chyu gm 4 tn hiu sau:

MSYN tch cc. SSYN b tch cc p li tn hiu MSYN. MSYN c o p li tn hiu SSYN b (tch cc). SSYN b c o p li tnh hiu MSYN khng tch cc.

Ta c thnhn thy bt tay ton phn l c lp thi gian, mi skin c gy ra bi 1 skin trc chkhng phi bi xung BUS clock. Nu 1 cp master-slave no hot ng chm th cp master-slavektip khng hbnh hng. Tuy u im ca bus bt ng brt r rng, nhng trong thc tphn

ln cc bus ang sdng l loi ng b. Nguyn nhn l cc hthng sdng bus ng bvi cc vimch ng bvtiu chun k thut, tc nhanh, khi lng bit ln, khon cch BUS ngn (trn mt bomch ch) v dthit khn. CPU chcn chuyn cc mc tn hiu cn thit sang trng thi tch cc lbnhp ng ngay, khng cn tn hiu phn hi. Chcn cc la chn ph hp th mi hot ng utri chy, khng cn phi bt tay.

2.2.5 Trng ti BUS (bus arbitration)

Trong hthng my tnh khng phi chc CPU lm bus master, cc chip I/O cng c lc lm bus masterc thc hay ghi bnhv gi ngt. Cc bng xl cng c thlm bus master. Nh vy ny

sinh ra vn : iu g sxy ra khi 2 thit btrln ng thi cn lm bus master? T cn c mt cchphn xtrnh shn lon ca hthng. C chphn xc thl tp trung hay khng tp trung.

Trng ti BUS tp trung

Nhiu vi xl c n vphn xc chto nm ngay trong chip CPU, trong mt smy tnh mini,n vny nm ngoi chp CPU. Theo c chny th b trng ti (arbiter) ch c thbit c yu cuchim dng bus hay khng m khng bit c bao nhiu n vmun chim dng bus. Khi arbiternhn

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c yu cu, n spht ra 1 tn hiu cho php trn ng dy (bus grant: cho php sdng bus). ngdy ny ni qua tt ccc thit bI/O theo kiu ni tip. Khi thit bnm gn arbiternht nhn c tnhiu cho php, n kim tra xem c phi chnh n pht ra yu cu hay khng. Nu c th n schimly bus v khng truyn tip tn hiu cho php trn ng dy. Nu khng th n struyn tn hiu chophp ti thit bktip trn ng dy, vi thit bny svic xy ra ging thit btrc n, qu trnh

ctip din cho n khi c mt thit bchim ly bus. S xl nh vy c tn gi l chui quay vng(daisy chaining). im ni bt ca s ny l cc thit bc gn thtu tin tuthuc vo vtrca n so vi arbiter, thit bgn hn th mc u tin cao hn.

Hnh 2.10 BUSchui quay vng daisy chaining)

Trng ti BUSMt sloi bus c nhiu mc u tin, vi mi mc u tin c ng yu cu bus (bus request) vng dy cho php bus (bus grant). V d: gis1 bus c 2 mc u tin 1 v 2 (cc bus thc tc 4, 8hay 16 mc). Mi thit b trong h thng my tnh ni vi 1 trong cc mc yu cu bus, cc ngthng c sdng nhiu hn c gn vi ng dy c mc u tin cao hn. v du, cc thit b1,

2 sdng mc u tin 1, cn cc thit b3, 4 sdng mc u tin 2.

Hnh 2.11 Trng ti BUS

Nu c mt sthit bcc mc u tin khc nhau cng yu cu, arbiter chpht ra tn hiugranti viyu cu c mc u tin cao nht. Trong scc thit bc cng mc u tin, thit bno gn arbiterhnsu tin hn. Vmt kthut, khng cn ni ng grant level 2 gia cc thit bv chng khng baogii hi bus mc 2. Tuy nhin, trong thc tthun tin cho vic lp t ngi ta hay lm nh sau:

P

T

I

T


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ni tt ccc ng grant thng qua tt ccc thit b, nh vy sddng hn l ni cc ng grantmt cch ring bit, v t cn cvo thit bno c quyn u tin cao hn.

Mt trng ti BUS c ng dy th3 ni ti cc thit bcc thit bxc nhn nhn ctn hiu grant v chim dng busng tn hiu xc nhn ACK (acknowledgement). Ngay sau 1 thit bpht tn hiu tch cc trn ng dy ACK, c tho tn hiu trn cc ng dy request v grant xungmc khng tch cc. Cc thit bkhc c th yu cu bus khi thit bu tin ang dng bus. Khi struyn thng kt thc, bus master ktip sc la chn. Cch lm vic nh vy lm tng hiu qusdng bus, nhng cn thm 1 ng truyn tn hiu v cu trc thit bcng phc tp hn. Cc chip trongmy tnh PDP-11 v cc chip Motorola lm vic vi cc bus nh vy.

Trng ti BUS khng tp trung

Trong Multibus, ngi ta cho php c thla chn sdng phn xbus tp trung hay khng tp trung, cchphn x

bg_xaydungcachethongnhung.pdf

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