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GSM Based Temperature Monitoring System


By Guided bySujadevi.S. Mr. Asni.H.DeepuDevaraj Mrs. Sumol

Elby Basil

ABSTRACT

In recent years industrial automation and control systems are an integral part of an industry

and hence the project temperature monitoring system is an important system in this state of affairs.

TMS aims at monitoring the temperature statistics in a factory, room etc, and controlling

peripheral systems. It uses embedded technology from Intel Corporation and built for application in

highly sensitive and critical systems.

Through the system we try to bring down the overhead involved in monitoring the

temperature statistics in various fields such as factory, air condition areas etc. With the obvious and

immediate usage as a system controller it is a complete implementation of dynamic system

management.

The system is aimed to meet the following prerequisites:

• To sense the temperature

• To display the temperature

• To display the date and time

• To set temperature limits

• To control the connected systems

• To save the history of limit crossings

Advantages

In a dynamic scenario wherein the breed and nature of real time systems are subjected to

promising changes TMS is aimed at adding the fundamental functionality of interfacing them with

varying ambience enabling them to be stable and reliable.


BLOCK DIAGRAM:

Department of Electronics and Communication. SNGCE, Kolenchery


Temperature Transducer 1 2 Channel

ADC------*------

Display

■t

M Cont

cro roller

Level w GSMTranslator Module


GSM Channel


Temperature Transducer 2

DC Power Supply

AC Source



CIRCUIT DIAGRAM:

ycc


I


PI 0/T2 PO.O/ADO

P1.1/T2-EX PO 1/AD1

P1 2 P0.2/AD2

PI.3 PO 3/AD3

PI 4/SS P0.4/AD4

P1.S/MOSI P0.5/AD5

PI 6/M1SO P0.6/AD6

PI 7/SCK PO 11 AD 7

P2 0/A8

P3 7/RD P2 1/A9

P2 2/A10

P3 6/WR P2 3/A11

P3 5/T1 P2 4/A12

P3 4/TO P2.5/A13

P3 3/iHJJ P2 6/A14

P3 2/INTO P2.7/A15

RST ALg/PROG

EA/VPP

XTAL2 P3 0/RXD

P3 1/TXD

XTAL1 Z


I

CONNECTOR DB9


BLOCK DIAGRAM DESCRIPTION

SIGNAL CONITIONING CIRCUIT: -

Signal conditioning circuit consists of two temperature transducers and an Analog to

Digital Converter. The transducer converts the temperature to proportional electrical signal.

The Temperature sensor used here is LM35 which has a resolution of

1 ° Celsius.

ANALOG TO DIGITAL CONVERTER:

An 8 Channel ADC is used since there is more than one sensor output that should be

converted into digital format before feeding to the Micro Controller.

INTERFACING OF GSM UNIT: -

Interfacing of GSM unit through a serial communication link with

microcontroller 89S51. Whatever data is to be sent to GSM unit is done through this RS 232

link.

LEVEL TRASLATOR: -

Level translator Translates TTL voltage level to RS-232 compatible level. It

is realized with MAX 232.


SIGNAL CONDITIONING CIRCUIT:

Signal conditioning is widely used in the word of data acquisition. Signal

conditioning circuit have two parts- two temperature transducers and an analog to digital

converter.

Transducer Section (Temperature Sensor) LM 35:

VCC LM35D

1—A

Transducers convert physical data such as temperature, light intensity, flow

and speed to electrical signals. Depending on the transducer the output produced is in the

form of voltage, current, resistance or capacitance.

The temperature transducers convert temperature into electrical parameters,

e.g.: thermistor, thermocouple. A thermistor responds to temperature change by changing

resistance but its response is not linear. Simple and widely used temperature sensors include

the LM 34 and LM 35 series.

The LM 35 series sensors are 3 pin precision integrated circuit temperatures

whose output voltage is linearly proportional to the Celsius (centigrade) temperature. The

LM35 thus has an advantage over linear temperature sensors calibrated in 0 Kelvin, as the

user is not required to subtract a large constant voltage from its output to obtain convenient

Centigrade scaling. The LM35 does not require any external calibration or trimming to

provide typical accuracies of ±1/4°C at room temperature and ±3/4°C over a full -55 to

+150°C temperature range. It can be used with single power supplies, or with plus and minus

supplies. As it draws only 60 uA from its supply, it has very low self-heating, less than 0.1

°C in still air.

+VS g VOUT


Features:

> Calibrated directly in ° Celsius (Centigrade)

> Linear + 10.0 mV/°C scale factor

> Rated for full -55° to +150°C range

> Suitable for remote applications

> Operates from 4 to 30 volts

> Less than 60 uA current drain

Analog to Digital Converter 0808:

vcc


+VS VOUTGND LM35D

+VS VOUTGND LM35D

vcc


Analog to digital converters are among the most widely used devices for data

acquisition. Microcontrollers use binary (discrete) values, but in the physical world

everything is analog (continuous). Here the output of LM 35 is an analog signal in the form

of voltage. Therefore, we need an analog to digital converter to translate the analog voltage

to digital form so that the microcontroller can read and process them.

An 8 Channel ADC is used since there is more than one sensor output that should be

converted into digital format before feeding to the Micro Controller.


Both the sensor outputs are fed to the two different channels of ADC 0808.The channels are

selected using the select pins which are controlled according to the signals from micro

controller.

The ADC0808 is a monolithic CMOS device with an 8-bit Analog-to-Digital

converter, 8-channel multiplexer and microprocessor compatible control logic. The 8-bit A/D

converter uses successive approximation as the conversion technique. The converter features

a high impedance chopper stabilized comparator, a 256R voltage divider with analog switch

tree and a successive approximation register. . The 8-channel multiplexer can directly access

any of 8-single-ended analog signals. The device eliminates the need for external zero and full

scale adjustments. Easy interfacing to microprocessors is provided by the latched and decoded

multiplexer address inputs. The ADC0808 offers high speed, high accuracy, minimal

temperature dependence, excellent long-term accuracy and repeatability, and consumes

minimal power. These features make this device ideally suited to applications from process

and machine control to consumer and automotive applications.

In ADC 0808. Vref (+) and Vref (-) set the reference voltage. If Vref (-) =

GND and Vref-(+) = 5V, the step size is 5v/256 = 19.53mv. Therefore to set a lOmv step size

we need to set Vref (+) = 2.56v and Vref (-) = GND. SC is for Start Conversion. SC is the

same as the WR pins in other chips. EOC is for End Of Conversion and OE is for Output

Enable (READ). The EOC and OE are the same as INTR and RD pins respectively.

The ADC 0808 has no self clocking. So the clock must be provided from an

external source to the CLK pin. Although the speed of conversion depends on the frequency

of the clock connected to the CLK pin, it cannot be faster than lOOmicrosecs.


Timing diagram


3C


0U1PJT t<lH.( '


'iOC f


< >


Features:

> Easy interface to all microprocessors

> 8-channel multiplexer with address logic

> OV to 5V input range with single 5V power supply

> Outputs meet TTL voltage level specifications

> Resolution 8 Bits

> Single Supply 5 VDC

> Conversion Time 100 ms

CLOCK GENERATOR:

An astable multivibrator using IC 555 is used here for providing the clock

signals. The frequency of the clock signal is 500Hz. NE 555 is a timer IC configured as the

frequency running oscillator provides the clock for ADC. It is basically switching circuit that has

two distinct output levels. As a result the circuit continuously switches back and forth between

two unstable states. In other words, circuit oscillates and output is a periodic rectangular

waveform. Since neither output


state is stable, then circuit is said to be astable and is often referred to as free running or

astable multivibrator.

In the circuit, the capacitor, the timing capacitor is charged towards +Vcc

through Rl and R2. The charging time Tl is given as

T1=0.693(R1+R2)C1.

This is the time during which output is high. The timing capacitor CI is then

discharged towards GND through the resistor R2. The discharge time T2 is gives as

T2=0.693R2.C1

This is the time during which the time is low. The period T of the oscillating clock is

the sum of Tl and T2. Thus

T= Tl+T2= 0.693(R1+2R2).C1

The frequency oscillation is then found as

F=1/T=1.44/(R1+2R2)C

V „ + 5 V

O/P CLK


MICROCONTROLLER 89S51:

The AT89S51 is a low-power, high-performance CMOS 8-bit

microcontroller with 4K bytes of downloadable Flash programmable and erasable read-only

memory. The on-chip downloadable Flash allows the program memory to be reprogrammed

In-System through an SPI serial interface or by a conventional nonvolatile memory

programmer. The AT89S51 provides the following standard features: 4K bytes of

downloadable Flash. 128 bytes of RAM, 32 I/O lines, programmable watchdog timer, two

data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full

duplex serial port. In addition, the AT89S51 is designed with static logic for operation down

to zero frequency and supports two software selectable power saving modes. The Idle Mode

stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to

continue functioning. The Power-down mode saves the RAM contents but freezes the

oscillator, disabling all other chip functions until the next external interrupt or hardware reset.

Features:

> 4K Bytes of In-System Reprogrammable Downloadable Flash Memory

> 4V to 6V Operating Range

> Fully Static Operation: 0 Hz to 24 MHz

> 128 x 8-bit Internal RAM

> 32 Programmable I/O Lines

> Three 16-bit Timer/Counters

> SPI Serial Interface

AT 89S51 Serial Programming

The microcontroller AT 89S51 can be programmed in both serial mode and parallel

mode. The Serial programming was carried out as it does not required extra burning module.

The serial programming of AT 89S51 is done using the personal computer, through the

printer port. The AT89S51 in its serial mode programming mode is shown in the figure.


P

;i ' ...................


AD DR.

QOOOB'FFFHSEE FLASH

PRCGRA'vlMINCH MODES TABLE

3-33 MHz

PGM DATA

PROG

RDY/ BSY

PI 0-P1.7P2.0 - P2.3PGP2.6

P2.7 P33 P3.6 P3..7ALEXTAL2E

AP3.0XTAL

IRSTGNDPS EN

AT89S5AO - A7

A8-A11


The microcontroller AT 89S51 is serially programmed using the software ATMEL

ISP Flash Programmer Version 3.0 through the printer port of the computer.

Serial Programming Algorithm

To program and verify the AT89S52 in the serial programming mode, the following

sequence is recommended:

1. Power-up sequence: Apply power between VCC and GND pins. Set RST pin to "H". If a

crystal is not connected across pins XTAL1 and XTAL2, apply a 3 MHz to 33 MHz clock to

XTAL1 pin and wait for at least 10 milliseconds.

2. Enable serial programming by sending the Programming Enable serial instruction to pin

MOSI/P1.5. The frequency of the shift clock supplied at pin SCK/P1.7 needs to be less than

the CPU clock at XTAL1 divided by 16.

1. The Code array is programmed one byte at a time by supplying the address and data

together with the appropriate Write instruction. The write cycle is self timed and typically

takes less than 1 ms at 5V.

2. Any memory location can be verified by using the Read instruction which returns the

content at the selected address at serial output MISO/P1.6.

3. At the end of a programming session, RST can be set low to commence normal device

operation.

The connection diagram with the pins of the serial port for serial

programming of AT 89S51 is as shown in the figure below

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LIQUID CRYSTAL DISPLAY:

Liquid state have been called the fourth state of matter(after solids, liquids and gases)

because they have certain crystal properties normally found in solids, yet flow like liquids.

Unlike LEDs and other electronic devices, LCDs do not generate light energy, but simply

alter or control existing light to make selected areas appear bright or dark.

There are two fundamental ways in which liquid crystal are used to control properties

of light and therefore after its appearance. In the dynamic scattering method, the molecules

of the liquid crystal acquire a random orientation by virtue of an extremely applied electric

potential. As a result light passing through the material is reflected in many different

directions and has a bright frosty appearance as it emerges.■

In the absorption method the molecules are oriented in such a way that then after the

polarization of light passing through the material. Polarizing filters are used 2 absorb or pass

the light depending on the polarization it has given, so light is visible only in those regions

where it cam emerge from the filter.

In recent years, LCD is finding wide spread use of replacing LEDs. This is due to the

following reasons:

1. The declining prices of LCDs.

2. The ability to display numbers, characteristics and graphics. This is in

contrast to LEDs which are limited to numbers and a few characteristics.

3. In corporation of a refreshing controller into the LCD, thereafter relieving

the CPU of the task of refreshing the LCD. In contrast, the LED must be refreshed

by the CPU to keep displaying the date.

4. Ease of programming for characteristics and graphics.

The connection of LCD with microprocessor is shown in the figure.

LCD INTERFACE:

vcc


The 8-bit data pins, D0-D7, are used to send information to the LCD or read the

contents of the LCDs internal registers. To display letters and numbers, we send ASCII

codes for the letters A-Z, a-z and numbers 0-9 to these pins while making RS=1( to select

data registers).

There are also instruction command codes that can be sent to the LCD to clear the

display or force the cursor to the home position or blink the cursor.

We also use RS=l(to select command register) to check the flag bit if the LCD is ready to

receive information. The flag is D7 and can be read when R/W=l and ■ RS=0. When D7=l

(flag=l), the LCD is taking care of internal operation and will not accept any new

information. When D7=0, the LCD is ready to receive new information.

;i ' ...................


RS 232 INTERFACE:

5 V


16

'CC

0 VJT

C3t ^ 1 uF

„..:... + 8 5 v

......-.........► -3.5 V

C4'X^ 1 uF

EIA-232 Output EIA-

232 Output EIA-232

input EIA-232 Input

1ci 1 uf34C2 — 1 MF5I 11From CMOS or TTL <",10I,12| ^.....................To CMOS or TTL <.91, *"

CBYPASS = 1 U'F

C1 +

C1-

C2+

C2-

14

13


I 15 GND

Serial port is harder to interface than parallel port. In most cases, any device you

connect to serial port will need the serial transmission converted back to parallel so that it can

be used. This can be done using a UART. On the software side of things, there are many

more registers that you have to attend then on a standard parallel port (SPP). Serial cables can

be longer than parallel cables. They also do not need as many wires as parallel transmission.

RS 232 stands for Recommended Standard 232. RS 232 is the most widely used

serial I/O interfacing standard. This standard is used in PCs and numerous types of

equipment.

In RS 232, a l is represented by -3 to -25V while a 0 is represented by +3 to

+25V,making -3 to +3 undefined where as a serial port transmits a 0 as 0V and l as 5V. This

standard was set long before the advent of the TTL family, its input and output voltage levels

are not TTL compatible. For this reason to connect any RS 232 to a microcontroller system

we must use voltage converts such as MAX 232 to convert the TTL logic levels to the RS

232 levels and vice versa.


MAX 232:

The 8051 has two pins that are used specifically for transferring and receiving data

serially. These two pins are TxD and RxD which are TTL compatible. Therefore this

requires a line driver to make their RS 232 compatible. One such line driver is the MAX 232

chip from maximum co-orperation.the MAX 232 converts from RS 232 voltage levels to

TTL voltage levels and vice versa. One advantage of the MAX 232 chip is that it uses a +5V

power source which is the same source voltage for the 8051. In other words with a single

+5v power supplies we can power both 8051 and MAX 232, with no need for the dual

power supplies that are common in many older systems.

The MAX 232 has two sets of line drivers for transferring and receiving data. The

line drivers used for TxD are called Tl and T2 which the line drivers for RxD are designated

as Rland R2. In many applications only one of each is used. Here also used only one set of

transmitter and receiver Tl and Rl.MAX 232 requires four capacitors ranging from 1 to

22microF.the most widely used value for these capacitors is 22microF.


GSM EQUIPMENT:

Introduction to GSM:

GSM (Global System for Mobile Communications) is world's most famous Mobile

platform. Mobile phones with SIM cards use GSM technology to help you communicate

with your family, friends and business associates.

GSM systems have following advantages over basic land line telephony systems:

1. Mobility

2. Easy availability

3. High uptime

We use communication feature of Telephone landlines for internet, e-mail, data

connectivity, remote monitoring, computer to computer communication, security systems. In

the same way we can use GSM technology and benefit from its advantages.

Uses GSM technology for following applications:

1. Access control devices: Access control devices can communicate with servers and

security staff through SMS messaging. Complete log of transaction is available at the head-

office Server instantly without any wiring involved and device can instantly alert security

personnel on their mobile phone in case of any problem.

2. Transaction terminals: EDC (Electronic Data Capturing) machines can use SMS

messaging to confirm transactions from central servers. The main benefit is that central

server can be anywhere in the world.

3. Supply Chain Management: With a central server in your head office with GSM

capability, you can receive instant transaction data from all your branch offices, warehouses

and business associates with nil downtime and low cost.GSM UNIT:

The GSM Modem supports popular "AT" command set so that users can develop

applications quickly. The product has SIM card holder to which activated SIM card is

inserted for normal use. The power to this unit can be given from UPS to provide

uninterrupted operation. This product provides great feasibility for devices in remote location

to stay connected which otherwise would not have been possible where telephone line do not

exist.

"AT" COMMANDS:


AT commands, also called Hayes AT commands, are based on the Hayes Modem de

facto standard, ATTENTION Commands for modems. They are used to communicate with

your modem. These commands modify your modem's behaviour or instruct the modem to do

something specific, such as dialling a telephone number. The "AT" refers to getting the

Attention of your modem.

To send a command to modem, we need to start a terminal program such as

Windows Hyper Terminal .No matter which terminal program you use, it should be

configured to communicate with the COM port that your modem is attached to. You then

type commands in the Terminal window. The modem executes the command and responds

appropriately. One set of AT commands will identify your modem and version information.

Eg: -ATD [<dial_string>][;]

Dials the phone number specified in the <dial string>parameter.

INTERFACING OF GSM UNIT:

Interfacing of GSM modem is done through a serial communication link between the

modem and microcontroller 89S51. Whatever data is to be sent to GSM modem is done

through this RS 232 link. The different initialising signals and commands are sent as data

packets.


APPLICATIONS OF GSM MODULE:

1. Remote Condition Monitoring:

Wire free telemetry allows the early identification of a problem and can save

expensive down time and repair costs. Automated data collection means the information is

available at any time, any place, saving costly visits to site. In a typical remote industrial

monitoring application, when perhaps a cellular solution is being used to check the status of a

machine using GSM, then the use of a wireless monitor comes into its own.

2. Data Capture for Remote People Counting:

Remote monitoring techniques used in conjunction with suitable sensors

are used capture data and count people in retail outlets. By knowing how many people have

entered or left each establishment then the effectiveness of sales and marketing campaigns

can be monitored. When used in conjunction with RFID then the movement of staff can be

monitored which is particularly appropriate in areas where there are a lot of staff and

relatively few customers. By monitoring footfall remotely the data can be viewed centrally,

so you could look at many stores across regions to compare effectiveness geographically.

3. Wire Free Security Alarms:

Wire free security alarms using cable free motion detectors and GSM capable

communication devices for sending text messages are well suited to building sites, temporary

offices. The lack of cable means that the can be installed very quickly, location of sensors

can be quickly altered to suit the changing needs of the building and alarms can be quickly

and easily configured to be sent to mobile phones. The remote alarm system can also works

without mains power.


POWER SUPPLY SECTION:


D1 4- ^

U1IN OUT Q


C1 C2


T2

C78L05


V1

D3

►f

The power section consists of a transformer, bridge rectifier and voltage regulator.

This project uses a transformer of 230V ac primary to 0-9V, 1A secondary. A transformer

isolates dc supply from ac main. The bridge rectifier converts AC signal into DC and is

filtered using capacitor filter. Its output voltage changes when load current or line voltage

varies. An electronic circuit which keeps the output voltage constant irrespective of the

variation in the load current, line voltage and temperature is an electronic voltage regulator.

This is added at the output of the unregulated power supply.

The voltage regulator is a circuit that provides a precision output voltage under

varying load condition and possibly varying input voltage. Here we need a +5V so that the

output of the filter is fed to LM 7805, a voltage regulator which gives an output voltage of

+5v dc.

Voltage Regulator LM7805C:

The LM78XXC monolithic 3-terminal positive voltage regulators employ internal

Current-limiting, thermal shutdown and safe-area compensation, making them essentially

indestructible. If adequate heat sinking is provided, they can deliver over 1 .OA output

current. They are intended as fixed voltage regulators in a wide range of applications

including on-card regulation for elimination of noise and distribution problems associated

with single-point regulation. In addition to use as fixed voltage regulators, these devices can

be used with external components to obtain adjustable output voltages and currents.


Block diagram:


I N P U Tl O —

S E R E Sp a s s

EIEMEN1

OUTPUT— O Z


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Features:

> Complete specifications at 1A load

> Line regulation of 0.01 % at 1A load

> Load regulation of 0.3%

> Internal thermal overload protection

> Internal short-circuit current limit

O


SOFTWARE

IDE- KEIL uVision:

The software for GSM based temperature monitoring system is

written in Assembly language of 8051. The program is assembled using KEIL pVision

assembler which is available in the internet. pVision, from Keil Software, combines Project

Management, Source Code Editing, Program Debugging, and Flash Programming in a

single, powerful environment.

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fig. Screenshot of KEIL micro vision


FLOW CHART:

START

INITIALISE ALL PORTS TO FFH

DISABLE ALL INTERRUPTS

INITIALISE THE DISPLAY

INITIALISE UART WITH BAUDRATE 9600

1

READ DATA FROM ADC

DISPLAY PRESENT TEMP AND LIMIT

1x YES rSEND FORMATTEDMESSAGE TO GSM UNIT

STOP


ALGORITHM:

Stepl: Initialise all Ports to FFH

Step2: Disable all interrupts.

Step3: Initialise LCD and UART with Baud Rate 9600 Step4:

Read the output of ADC from both the channels Step5:

Display the present temperature and limit Step6: Compare

present temperature with the limit set.

Step7: If limit is crossed, send the formatted information to the GSM unit through serial

communication link else go back & read the ADC outputs.


ARTWORK:


CONCLUSION:

GSM Based Temperature Monitoring System was a project based on

microcontroller, due to which hardware requirement is reduced. Modifying the software will

be enough for further enhancement of our project. In a dynamic scenario wherein the breed

and nature of real time systems are subjected to promising changes, this project is aimed

adding the fundamental functionality of interfacing them with varying ambience enabling them

to be stable and reliable.

By doing this project, we were better able to understand the various

facets of doing an embedded system project which is emerging as one of the most 'in demand'

technologies right now. Eventhough this project was developed to alert in crucial

circumstances, this can be expanded for controlling the temperature also.

The development of this project has shown how much hard work goes

into the creation of a system. Embarking of this project has helped us in developing a team

spirit, patience and time management necessary for today's technical professionals. This

project has built in us confidence that any problem can be solved with sheer determination,

hard work and optimism.


APPENDIX


APPENDIX - A

SOURCE CODE:

/* PORT ASSFNGMENT:-P0->LCD DATA LINES P1->ADC DATA P3.4->SELECT LINE A P3.5->SELECT LINE B P3.6->SELECT LINE C P2.5->LCD RS P2.6->LCD E P2.7->LCD R/W */

ORG 0000H AJMP 0020H; ORG 0020H

MAINE


LOC:

MOV P1.#0FFH; ACALL DISPINIT; MOV A,#80H; ACALL CWRT; ACALL DORG; MOV A,#0C0H ACALL CWRT; ACALL DORG1; ACALL ADCREAD; MOV R5,#0FFH; ACALL DELAY; MOV R5,#0FFH; ACALL DELAY; MOV R5.#0FFH; ACALL DELAY; JMP MAIN1 ;PORT 1 AS I/P

FIRST LINE OF LCD

INITIALIZING ;SECOND LINE OF LCD


DISPLAY ORG IN** *

DORG:


CLR A;MOV DPTR,#8F8H; ACALL DSEND; MOV R5,#02H;

LOADING; CALL

DELAY;


ACALL DELAY; RET;

SPLAY ORG IN 1

DORG1:


CLR A;MOV DPTR,#911H; ACALL DSEND; RET;

LOAD GSM TEMP


I* ****************** DISPLAY INITIALISATION* * *******************/

DISPINIT:


MOV A,#38H; ACALL CWRT; MOV A,#14H;

ACALL CWRT; MOV A,#0CH;

ACALL CWRT; MOV A,#01H; ACALL CWRT; RET;

LCD 5*7&2LINES

DISPLAY ON CURSER NOT BLINK

DISPLAY ON CURSER NOT BLINK

DISPLAY CLEAR


COMMAND WRITE TO LCD**********************/

CWRT:


MOV P0,A; CLR P2.5; SETB P2.6; ACALL SDELAY; CLR P2.6; ACALL SDELAY; SETB P2.6; RET;

RS->0 E->1

E->0

E->1


/********************Q^'T'^ WRITE TO LCD*************************/

DWRT:MOV P0,A;SETB P2.5; RS->1SETBP2.6; E->1ACALL SDELAY;CLR P2.6; E->0ACALL SDELAY;.SETB P2.6; E->1ACALL SDELAY;RET;

SHORT DELAY*******************/

SDELAY:MOV R3,#10H;

LOCI: DJNZ R3,LOCl;R E T ;

/*************************L)ATA SEND TO

LCD**************/ DSEND:CLR A;ACALL SDELAY; MOVC A,@A+DPTR; CJNE A,#00H,LOC4; RET;

LOC4:ACALL DWRT; INC DPTR; SJMP DSEND;

DELAY: MOV R4, #0FFH;HERE: DJNZ R4, HERE;

DJNZ R5, DELAY;RET;

A D C R E A D :MOV P1,#0FFH; PORT 1 AS I/PCLR P3.4;CLRP3.5; ADD SELECTCLR P3.6;CLR P3.7;ALE


ACALL SDELAY;SETB P3.7;ACALL SDELAY;CLR P3.7;MOV R5,#010H;CALL DELAY;MOV A,P 1; READING ADCANL A,#1FH;MOV R7.A;SETB P3.5;CLR P3.7;ALEACALL SDELAY;SETB P3.7:ACALL SDELAY;CLRP3.7;MOV R5,#010H;CALL DELAY;MOV A,P1;ANL A,#1FH;ADD A,R7RRC A;MOV R6.#030H; JC FIVE;

CARRY: MOV R7,A;C L R CSUBB A,#018H; JNC ALARM; MOV A.R7; ACALL CONVE; MOV A,R0; ACALL DWRT; MOV A,R1; ACALL DWRT; MOV A.R2; ACALL DWRT; MOV A,#02EH; ACALL DWRT;MOV A,R6; ADDING DECIMAL POINT &

DISPLAY

ACALL DWRT;

LOC3: RET;

^** S I :******** H < * * * * * *I_JC7^ TO f3CD (CONVERSION***********************/

CONVE:MOV R(),#30H; MOV R1,#30H; MOV R2,#30H MOV B,#02H; MUL AB; MOV B,#64H


LOC2:

DIV AB; ADD A?R0 MOV RO.A; MOV A,B; JZ LOC2; MOV B.#0AH; DIV AB; ADD A.Rl; MOV Rl.A; MOV A,B JZ LOC2; ADD A,R2; MOV R2,A; RET;

GSM Based Temperature Monitoring Syste

ALARM* * ************* **/


ALARM:


MOV A,#01H; ACALL CWRT; MOV R5,#02H; ACALL DELAY; MOV A,#80H; ACALL CWRT; MOV R5,#02H; ACALL DELAY; CLR A;MOV DPTR,#91BH; ACALL DSEND; CALL SERIALROUTINE; JMP LOC3;

CALL DELAY;

CALL DELAY;


y***************** * *S£RiALROUTINE* * *******************************/

SERIALROUTINE:

UARTINIT:


MOV TMOD,#020H;#10H

MOV TH1,#0FDH MOV SCON,#050H;#10H SETB TR1 CLRTF1MOV PCON,#070H

TIMER1 IN MODE [(ADC)JIMERO IN MODE 2(RS232) BAUD RATE SET SERIAL MODE

RUN TIMERO


• ******************************************************************!(:*


;TX_CHAR TRANSMIT ONE CHAR. THRO' SERIAL INTERFACE ;INPUT CHAR. TO BE TRANSMITTED IN ACC.

TX CHAR:


TRANS 1:

SKIP:

HERE2:

MOV DPTR,#800H

MOV R5,#010H ACALL DELAY CLR AMOVC A,@A+DPTR; CINE A,#00H,SKIP JMP OVE;

INC DPTR; MOV SBUF, A

JNB Tl, HERE2 CLR Tl


SKIPTX:

OVE:

JMP TRANS 1;

RET:


/ DATA TO BE DISPLAYED**********


ORG 800H

ORG 900H

END

DB "ATD9995238051;" DB ODH: DB 00H

DB " INITIALIZING " DB 00H;DB "GSM TEMP:"; DB 00H;DB " ALARM!!!"; DB 00H;


(9 N a 11 o a a I S e m i c o n d u c t o rDecember 19S4

LM35/LM35A/LM35C/LM35CA/LM35D Precision Centigrade Temperature SensorsGeneral Description

T H E LM-JS series aio ptecWtan I ntogratod-ctcuit temperature sensors, whoso

output voltage is Hn early pro cot Her alto tho Celsius (Centigrade) temperature.

T H E LWLis thus has an advantage over linear temperature sensors calibrated m"

Kelvin, as the uses is rat teqiked to subtract a la<go ooiv slant voltage from its

output to obtain convenient Centigrade scaling. The LM3S doos rot iegutre any

external calibration or trimming to provide typical accuracies of i V/'C at toom

temperature ana ' %"C ov« a lull tb to -150*C tomporature range. Low cost Is

assuroa by trimming arc calibration at the wafer level. The LM3b's tow output

impedance, linear output, and precise inherent calibration make interfacing to

readout or control errantry especially easy. It can be used with single power

supplies, or with plus ana minus supplies. As it draws only 60 tiA from its supply, it

H A S very tow self-heating, less than 0.1"C in sUI a'sr. The LM3b is rated to operate

over a SS" to - 1S0"C temperature range, white the LM3bC is rated for a - 4 T Y to -

119*0 range { 10" with unproved accuracy). T H O LM35 series is available packaged

m hermetic TO-46 transistor packages, while the LM3bC, UvtSbCA. and LMSbD

are- also available m the plastic TO-92 transistor package. The LM36D « also

available m an 8-lead surface mount small outline package and a plastic TO-202

package.

Features■Calibrate ! .aoctfy in " Celsius (Centigrade)

■Linear - i\S mV/"C scale factor

■05"C accuracy guarantecaole (at - 2b"C>

■Rated (oi full bb" to - lbO"C range

■Suitable for remote applications

■Low cost due to wafot-level trimming

■Operates from 4 to 30 volts

■Less than 90 i«A aw rent drain

■Low self-lieatmg, 0.06*C I B still air

■Nonlineanty only x Vi"C typical

■Low importance output, 0.1 SI fen 1 mA load

Connection DiagramsTO-46 Metal Can Package*

TO-92 Plastic

Package

SO-8Small Outline Molded Package


j +'s WinSMD \

u jn.c.

ONC

"S II c.

CIiCTTBIK VW


lime is c<tfTi«':4w:i lu ntxjiilvy i

Order Number LM3SH. LM 36AH.

LM3bCH. LM36CAH or LM36DH See NS

Package Number H03H

TO-202 Plastic Package

Order Number LM35CZ. LM36CAZ or LM3bDZ

See NS Package Number ZD3A

Typical Applications-Us 14* TO mi

_Li-.'-niiio 2i

Top ViewHC ~ l*> Ois'rie<tfeet

Order Number LM36DM See NS Package

Number M08A

i-.-i/sbis i

I iGNDl


i» 35

Tt outwit' 0 arV * ICO n«V> G

17m <


I -1il I* 3

FIGURE 1. Basic Centigrade

Temperature Sensori ;-2"C to -

1bO"C)

TUM«5t« -i -

Vs.'» uA


It'lli^l'.i 2A

Order Number LM36DP See NS Package

Number PD3A

-i253 mV 4 • J5-C

- -«50 tivai -sre FIGURE 2. Full-Range

Centigrade Temperature Sensor


Absolute Maximum Ratings (Note 10}tl Military/Aerospace specified devices are required, please contact the National

Semiconductor Sales Olfice/Distributors lor availability and specifications.

Supply Voltage - 36V to -0.2V

Output Voltage - 6V to - 1.0V

Output Cut rent 10 mA

Storage Temp.. TO-46 Package, 60"C to ■•■ 18CTC

TO-92 Package. WCto - 1S<TC

SO-B Package, 6S"Cto i 1 !>CTC

TO -202 Paskage, - 66"C to + 1 S'CfC

Lcaa Temp.:

TO-«6 Package. (Soldering. 10 seconds) 300"C

TO-92 Package, (SotdennR. 10 socoias) 26CTC

TO-202 Package. (Soldering. 10 seconds) -■ 23 OC

Electrical Characteristics lNotcD(Note6)

SO Package (Note 12): Vapoi Phase (60

seconds) Inlrarea (is seconds)

ESD Susceptibility- (Note 11!Spooled Operating Temperature Range: T,lt!H to TMAX (Note 2)

LM3S, LMS6A 55"Cto ; 1KTC

LM 3SC. LM3BCA - 40"C to + 110>'C

LM360 0"Cto ■>■ 100"C

21S"C 220


LM3bCA


ParameterConditions

Typical

Tested Limit

(Note A )

Design Limit

(Note bl Typical

Tested Limit

(Note +)

Design Limit

(Note bi

Units (Max.)


Accuracy (Note

1)

T A - ! Zb'i

T a- rye'0.2

-0.3

-0.4-0.4

t-0.b

11.0 v 1.0 I 0.2

.!. 0.3

I: 0.4 > 0.'.

.tO.Jt ±1.0

1.0 1.5


Morlirvea'% (Mote B)

T, Ta •'.T i ■ 0 . 1 0 • 0 . 3 5 0 . 1 5


Sorvsor Gam

(Avciago Slope)T I • T . 9 . 9 , 1 0 , 1

1 0 . 0i 9 . 9 , ■ 1 0 . 1 mV/'-C


Load Regulation (Note 3) 0

I;/ 1 M AT A - 2 &^ TU»iS T A TYAX 0 . 5 3 . 0

I: 0.*$

0 . 51.0

3 , 0 mV/ m A


L I R E Regulator (Note

D ) ta- 2re

4V1 V'si 30V•. 0.01 0 . 0 2 iO. O 0 . 1

:' 0.01 0 . 0 20 . 1

mV/V mV,.* V


Owe scent Current

(Note S)

V5 - - SV. - 2S*C Vs " - bV

V's «. - 30V. - 2S-C Vs ^ "

30V1 0 5

56.2 1 0 5 . 5

6?

661 3 1

1 3 3

9 1

ye.29 1 . 5

67 €-!>1 1 4 1 1 6

(JtA I* A M,A


Clvangoof Quiescent

Current (Note 3)

lV.-iVss.30V. • 25

'«V--;Vss30V0 2 0 . 5

2 . 0v'.<:

0 . 5


Te mporaturo Coefficient

of Ouiescert Currorl


Mini rn iirn T err per atuto lo>

Rated Accuracy

In 2tJ'l of figure

lf*0

1.5


Loi^g Term StabilityTj -TMAX. 'or 1000

hours

3.01' 0.0b


MAI* 1:UM*««t»rtiile«»ea.l^»6Sl*-fe«to!* *oy -55"C ',Tj'. ' ISCPCNSr tie LW3S »W LV05A. -«*.;Tj< ' 110*CtW»W LM»5C»*tU»SCA, »i<f0'-.Tj'. • 10Q'C tar tfxs Vs~ ^ ifld iiCAD"-* t'«r trmrt of rârt* ^. Tr'<***i *i4aK-id!a*s atsu j*sery lnw * 2*C te TJA^c in flur u-jut -:lKt/utu i 3pei:1'Oiittfis *i btrfdfaor a:>5% tv«* I?* fur rafc*J tetfncw*ahj* rir-^j

Noi* Th<*-rnal re*su.ioe ell.':*.* T04fc eaciwêia 420*C/W. junction fc sn&fcnt and 24*€rw ymctionlG case Thermal re**iarteeet TO 32 paoka§« :* 1 QO'CW pjictor te art*s*;nt Therms aslant* &f f?* *rjaii outline iTK>?<Je«f a^* is ^C'C/W sun«fw te arrive The^rîi fesst^c-ii ef tiis TO 2Q2 paAî


Typical Applications ccoo*

OH ltlk BHtOStSlFIGURE 6. Two-Wire Remote Temperature Sensor (Output

Referred to Ground)FIGURE 5. Two-Wire Remote Temperature Sensor (Grounded

Sensor)


0.1 »f

mam.

■ 1WS1KI VOW =lfl lW,"t lliXBitH *V€) FROM + 2"£TE) 4-49-C

V;u-'< ( I'Maaw ■ ,-r-:

,M y rm%m mm


IN*™ (

I 1m y m '«Ktt = 18 i»V/*C fteffljm «i»«C)l r

I FHSm -S'C K - wrc


i Russia >FIGURE 7.Ternperature Sensor, Single Supply, 66" TO tbO'C TUHflllM

FIGURE 8. Two-Wire Remote Temperature Sensor (Output Referred to

Ground)


, asOffKT *D0UST ,

ttffWSSI« «

FIGURE 9. 4-TO-2t>mA Current Source (0"C LO - 100"C!

T-'>|yaSl«~lO FIGURE 10. Fahrenheit Thermometer


FIGURE 11. Centigrade Thermometer (Analog Metcrl" TU M /5SW 12

FIGURE 12. Expanded Scale Thermometer (bO" to 80" Fahrenheit, tor

Example Shown)

FIGURE 13. Temperature To Digital Converter (Serial Output) (I 128"C Full Scale)

FIGURE \ 4. Temperature To Digital Converter (Parallel TRI-STATE* Outputs (or Standard Data Busto uP Interface)

(12B"C Full Scale)

Typical Applications (confinuea)


(9 Ar a l i o n a I S e m i c o n d u c t o rOctober 1995


ADC0808/ADC08098-Bit JJP Compatible A/D Converters with 8-Channel Multiplexer


General Description"he ACCS806. ADCC-J03 data acquisition conrporetrc is a monolithic CMOS c'ev'ce

with ar -3-bt anaiog-to-dtgita converter. 8-channel nwUo.exef ana microprocessor

compatible control log c. The 8-bit NO converter uses successive approximator as

the conversion technique. Trie convener features a high mpedance chopper stapilzed

comparator, a 256R voltage divider with anaog switch tree ano a successive

approximation register The ?-channel multiplexer can directly access any of 3-s-ngle-

ended anaog signals. ~he fi-evce eliminates the need for external zero and fU:l-scale

adjustments. Easy interfacing to microprocessors s provided by the atcneo and

cecoded multiplexer address nputs and l3tched TTL TRI-STATE*- outputs. The

design of the AQC0808. ADC880& has been optimized ay incorporating the most

desirable asoects of several Afl3 conversion techniques The ADCD80&. APC383&

offers h'gh speed high accuracy, minimal temperature dependence, excellent iong-

term accuracy and repeatability, and consumes minima! power. These features make

this device ideally suited to applications from process and machine control to

consumer ana automotive aao ications For 16-channel multiplexer wish common o-

dtput rsamp e'hold port) see ADC0816 data sheer (See AN-2<s7 'or more

nformaticn.i

Features

■ Easy rtfrtace to ail m preprocessors

■ Operates rationietricai'y or with 5 V-.0 or analog scar adjusted

voltage reference

» No zero or fj l-scale adjust required

■ 9-cfiannel multiplexer vvth address logic

■QV to 5V input range with single 5V power sups y

■Outputs meet TTL voltage level specifications

■ Standard hermetic or mooed 2&-pin DIP package

■ 2S-p.ii moided ch-p earner package

■ ADCOSC? equivalent to MM74C&49

■ AOCOati equivalent to MM74C949-1

Key Specifications■ Resolution

■ Total unadjusted Error

■ Singe Supply

■ Low Power

■ Conversion Time

6 Bits

± >/i LS8 and +1 LSS 5

15 mW

100 ms

http://2S-p.ii/


Block Diagram

T U H F tore*O l


3 I D T


IEIE

, ..■■4.1.1.1 ** I J W ' L > « U L » K "« — J—

1 1 111 ___l i lSee Ordering Information


Connection DiagramsMolded Chip Carrier Package

Dual-In-Line Package s a a■<■<■<

I I I 1 1 I 1Hi- 1 —

JR ?« u ,>i 70 •»fi* — ? ?r — iM wr,_ :■ i n

3 -M IH -— 11

we- 4 n -*C0 * M2- ::t lg r "miWK ?- 5 '.'4 -*» e 1 1?

sr«" - F. IS -«0 r *U _ ; 14 —

EOC- 7 223

13

!->-8 21 -2"'MSB 4 - '«ir(»>

WTPUT tH l fe t -CLOCk -

n

RSS ; F | B ; 10 1 !

IC -r5 1 1 1 1 1 1p, »a

11 ■o _ .-4 * S " Z ,-j'«if<«>- w '

7-r'TSA

a!

CND- 12 !T ~VHF <") 1

7"-'- ir» -r'

Order Number ADC 0808C CV orADC0609C

See HS Package V28A

Order number ADC0808CCN or ADC0809CCN See U S Package

J28A or M28A

Ordering InformationTEMPERATURE RANGE -40" C to +85'C -55'C to +126X

Error ±'/i LSB Ursaojjsted ADC0803CCN' AJ5CQ3CSCCV ADC06G3CCJ ADC0303CJ±1 LSB Unadjusted ADCOSOilCCi! ADC03SSCCV

p ackage Ciitire f.I&A N'.olcec DIP V2?A Molded Chic :."arrer J38A Cerarvi c DIP J2SA Ceramic CIP

Timing Diagram


|.._*4 s?*-fic A @ B »? U

• • • a

- Jt I


IR f J "H H Tt R*>H -a*DDI! _____________________: X X


a u fin

1

>

Functional Description■Multiplexer, The dev ce certains an 8-channel singe-ended analog signal mtntip exer. A

particular input channel is se-ected by using the address oecocer Tah<e ? Shows the

input states for the address lines to select any channel The address is latched into the

decoder on the ow-to-high transition of the address latc.n enab'e signa,

TABLE 1.

SELECTED ANALOG

CHANNEL

ADDRESS LIMEC B A

INP L L LINI L L HIN2 L - L

IN3 L :-; H

IN4 H L LIM5 H L HIN6 H H LIN7 H H H

CONVERTER CHARACTERISTICS The Converter

The heart of this singe chip data acquisition system * its 3-bit ana.og-to-digita converter.

The converter s des gneti to give fast, accurate, and reoeataole conversions over a wide

range of temperatures. The converter s partitioned into 3 major sections: the 2S6R

ladder network, the successive approximation register, and the comparator The

convener's digital outputs are positive true

The 256R adder network approach (Figure ?! was chosen over the conventional R/2R

adoer because of its Inherent monotonicity. which guarantees no missing d gita codes.

Monotonicity is part cu any important in closed loop feedback controisystems Anon-

monotomcrelationshipcan cause os-cii ations that will be catastroph c for the system.

Additionally, the 256R network does not cause load variations or, the reference voltage.

The bottom resistor and the top res-stcr of the ladder network in Figure > are not the

same value as the remainder of the network. The difference in these resistors causes

the output characteristic to m symmetrical wth the zero and full-scaie ooints of the

transfer curve The f rst output trans -ton occurs when the analog signal has reached +

1* LSB and succeed ng output transitions occur every 1 LSB ater up to fit -sea e

The successive approximation reg.ster (SAR) performs 8 iterations to approximate the

input voltage. For any SAR type converter, n-iteratons are required for an n-brt

converter. Figure 2 shows 3 typical example of a 3-bit converter. In fie ADC0803.

ADC0809. the approximator technique is extended to 8 bits using the 256R network.

The AID convener's successive appro-nation register (SAR) is reset on the positive

edge of the start conversion (SCI pulse. The conversion is begun on the failing edge of

the start conversion pu'M.A conversion n process w I be interrupted by rece pt of a re*'

star conversion puse. Continuous conversion may oe accomplished by tying the end-of-

conversion i'EOC; output to the SC input. If used in this mode, an external start

conversion pulse should be applied after power up Eno-of-eonversion wit go ew

between 0 arc 8 clock pu see after the rising edge of start conversion. The most

important section of the A/D converter is the comparator It is this section which is resp-

orsieie for the ultimate accuracy of the em re converter it is also the comparator dnft

which has the greatest influence on the reoeataWity of the device. A chopper-stabilized

comparator provides the most effective method of satisfying a:I the converter require -

ments

The chopper-stabi izeo comparator converts the DC input s'gnal into an AC signal. This

signal is then fed through a high gain AC amp ifier ana has tie DC eve restored. This

technique limits the dnft component of the amplifier since the dnft is a DC component

which is not passed by the AC amplifier. This makes the entire A/D converter extreme y

insen-s'tive to temperature long term dnft and input offset errors. Figure J shows a

typical error curve for the ADC2808 as measured using the procedures outlined in AN-

173.

Applications Information (Continued!

4.0 ANALOG COMPARATOR INPUTS

The dynamic comparator nput current «

caused by the periodic switching of on-

chip stray capacitances. These are

connected alternately to ttte output of the

resistor ladder: sw ten tree networK end

to the comparator input as part of the

operation of the choppe' stabilized

comparator.

The average value of the comparator

input current varies directly with clock

frequency and with V,N as shown in

Fiaure 6.

If no filter capacitors are used at

the ana ©g inputs signal source

impedances are low, the

comparator it rent shou-.O not

introduce converter errors, as the i

created by the capacitance

discharge w*l cie out ix comparator output is strobed. If

insut filter capacJors are desires

for noise reouc signal conditioning

they wi I tend to average out the

comparator input current. It wil

then take on the cha tics o* a DC bias current whose effect can be

predic vents5naKy.

Typical Application


READ■

AODFLESS DECODE-• I.AB*-ft0t5r

3>

5V STLPPI.V' 1

GRuuMO —

CL K OFU RE F I <; IQ

C.vntn i

7 'SIAJU =, -'>

2 -ALT N ]

2 'J

L

A ? '■'

AU E O M B

B AD C 080! ) 2 -6c 1 7

z *•aG M D

*

•

r '̂IP^x* ■n:i" 1

-#>INIERHUPT

M S 6

DI B

■> DBb -

¥ DS 4

1)83

-♦ • DS 2 -

►OB I

-> am

B-$VANALOG ■ INPUT RANEE

IKTERWHT

'M km-S'BMV-8

000 V ■

AD 0-

ADr-

AD J -

\— V|N« "I


'Ada-ess jh« -teed*: fcr 838J aw SOVB imrfecinsADCKCi tc a n£'-:cro:es*:r


Features• Compatible with MCS-51* Products

• 4K Bytes of In-Systetn Programmable (ISP) Flash Memory

- Endurance: 1000 Write/Erase Cycles

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 128 x 8-bit Internal RAM

• 32 Programmable I/O Lines

• Two 15-bit Timer/Counters

• Six Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

• Dual Data Pointer

• Power-off Flag

• Fast Programming Time

• Flexible ISP Programming (Byte and Page Mode)

DescriptionThe AT89S51 is a low-power, high-performance CMOS 8-bit microcontroller with 4K bytes of in-systen programmable Flash

memory. The device is manufactured using Atmel's high-density nonvolatile memory technology and is compatible with the indus-

try-standard 80C51 instruction set and pinout The on-chip Flash allows the program memory to be reprogrammed in-system or by a

conventional nonvolatile memory programmer By combining a versatile 8-bit CPU with in-system programmable Flash on a

monolithic chip, the Atmel AT89S5I is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many

embedded control applications.

The AT89S51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM. 32 I/O lines, Watchdog timer, two

data pointers, two 18-bit timer/counters, a five-vector two-level interrupt architecture, a fuM duplex serial port, on-chip oscillator,

and clock circuitry In addition, the ATS9S51 is designed with static logic for operation down to zero frequency and supports two

software selectable power saving modes The Idle Mode stops the CPU while allowing the RAM timer/counters, serial port, and

interrupt system to continue functioning The Power-down mode saves the RAM contents but freezes the oscillator, disabling all

other chip functions until the next external interrupt or hardware reset

8-bitMicrocontroller with 4K Bytes In-System Programmable Flash

AT89S51


Pin Configurations

PDIP


PI.CC Pl.t c P1.2C P1.3C

= • 4 C

lIVOS irt.SC

RVIOC. = • -: c

RSTC

IRXCI =s.:-ciTXC-i P3.- C (INTO)

P3.2 C JIRTTj = ;..?

C

4 c

itVPp - i f R

XTAU2 I; XTAU R G\C I

34

24

□VCC

□PC .of ADO:□PC". 1

CADI:□PC.2i.

A02;

□P0.3 |

AD3)

□PC.4 |

AD4;

□PC

5 ;AD5

]

□PC .6

lADBr

□PC.7 |AD7;

□E?.-V==

□A.-E-SSQG□P5EN

□P2.7

i.Aie! 3P2.6 |

A14;

□P2.5 |

A1J)

1P2.4

> A V

2 ) J

P2.3 |

A11> J P2.2

iA10)

1P2.1

iAS;

"]P2.0

I A3;

http://PC.2i.A02/

http://PC.2i.A02/


Block Diagram

A A A A A A A A A A A A A A A A

+ I 1 1 ~L { 1 F , » » » » » ▼ » ▼


=OR" 0 DRIVERS POR" 2 DRIVERS


l-IAM 6.0 Oilnut IS ILK

2 -x

i—_ , I , r


STACK -OltrE.RPROGRAM RE

SISTERBREGIS"^ACC

r3


UTERR JP~ SESIAL PORT *NC T«teR BLOCKS

PROGRAM COUNTER


3SEN « ALSPROG *

ANDCONTROL

rii~Ruc"ic.REGISTER


WATCHDOG

SORT 3

LATCH

i

r

PORT 3 DRIVERS

RTTITTTF A A A A A i i 4

ISP PROGRAM

PORT LOGIC

PORT 1 LATCH

PORT | DRIVERS


Pin Description

VCC Supply voltage.

GND Ground.

Port 0 Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eightTTL inputs. When Is are written to port 0 pins, the pins can be used as high-impedance inputs.

Fort 0 can also be configured to be the multiplexed low-order address'data bus during accesses to externa! program and data memory. In this mode, PO has internal pull-ups.

Port 0 also receives the code bytes during Flash programming and outputs the code bytes during program verification. External pull-ups are required during program verification

Port 1 Port I is an 8-bit bidirectional I/O port with internal puil-jps. The Port 1 output buffers cansink/source four TTL inputs. When 1s are written to Port I pins, they are pulled high by the interna! pull-ups ana can be usee as inputs As inputs. Port I pins that are externally being pulled low will source current (lfLi oecause of the interna! pull-ups.

Port 1 also receives the low-order address bytes during Flash programming and verification

Port Pin Alternate FunctionsPI.5 MCSI iuseci for In-System Programming}PI 6

MISO fused for h-System Programming)PI .7 SCK (used for In-System Programming;

Port 2 Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers cansink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull-ups and can be used as inputs. As inputs. Port 2 pins that are externally being pulled low will source current (l,,J because of the interna! pull-ups.

Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external oata memory that use 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to external oata memory that use 8-bit addresses (MOVX @ R|). Port 2 emits the contents of the P2 Special Function Register,

Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.

Port 3 Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output Duffers can

sink/source four TTL inputs. When Is are written to Port 3 pins, they are pulled high by the internal pull-ups and can be used as inputs As inputs. Port 3 pins that are externally being pulled tow will source current (y because of the pull-ups.

Port 3 receives some control signals for Flash programming and verification.

Port 3 also serves the functions of various special features of the AT89S51. as shown in the following table.


Port Pin Alternate FunctionsP30 RXD <senal input portsP3J TXD (senal output port)P3 2 INTO (external interrupt 0)P3.3 INT 1 (external interrupt i jP3.4 TO (timer 0 external input iP3.5 T1 (timer 1 external input)P3.6 WR {external data memory write strode;P3 7 W ) (external data memory read strobe)


RST Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. This pin drives High for 98 oscillator

periods after the Watchdog times out The DIS-RTO bit in SFR AUXR (address SEHi can oe used to disable this feature In the default state of bit

DISRTO, the RESET HIGH out feature is enabled.


ALE/PROG

Address Latch Enable (ALE) is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the

program pulse input (PROG) during Flash programming.

In normal operation. ALE is emitted at a constant rate of 1/6 the oscillator frequency and may oe used for external timing or clocking purposes.

Note, however, that one ALE pulse is skipped during each access to external data memory

If desired. ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC

instruction Otherwise, the pin is weakly pulled high Setting the ALE-oisab e bit has no effect if the microcontroller is in external execution

mode.


PSEN Program Store Enable (PSEN) is the read strobe to external program memory


When the AT8&S51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN

activations are skipped during each access to external data memory.


EA/VPP Externa! Access Enable. EA must be strapped to GND in order to enable the device to fetch code from externa! program memory locations

starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be infernally latched on reset.

EA should be strapped to Vcc for internal program executions.

This pin also receives the 12-voft programming enable voltage (Vpp) during Flash programming.


XTAL1

XTAL2

lput to the inverting oscillator amplifier and input to the internal clock operating circuit.

Output from the inverting oscillator amplifier Flash Prcgrammng and

Verification Waveforms - Para lei Mode

PRC-3RAMM N3 >? ONPI 0 - PL.7 P2.0 -

P 2 Z

PORT 0

> :CR = £3 A0-RE3.3

QA"A IN DATA OU

LOG C


EAjV, LOG C 3


(ENABLE)

P3.Q

i'RDY/BSYI surf Y R=ACV


Flash Memory Sena: Down oading


ATI9S51 O


V


INSTRUCTIONIHPUT ----------------*

DATA CHJTPJT *------------

CLOCK IN ----------------►

P l .c.'MOSipi.e/wiso

P1.7,'SCK

XTAU


3-33 M H z

XTAL1

GND

Flash Programming and Verification Waveforms - Serial Mode

, Serial Programming Waveforms

SERIAL DATA INPUT / MSB V V V V Y V Y -35

=i,s I;mosi. ________L_______T, ./v........................./v_.............j\__________________________________A „ ........._A___________________A_______________

£Wi DATA OUTPUT / Mk Y Y"" ~Y Y Y V Y i.sa \P I .6S M I S O J ___________________z_________,}.,........................../v.,.................A..............._A._.....................A...............-A__________________A._________________!


S5RIAL COCK INPUT Pi.7 iSCK'i

I I I I

r i j ' L l ..................i i ....run.

MAX232 . .. D. DW. n. OR NS PACKAGE

MAX232I. . D. DW, OR N PACKAGE (TOP

VIEW)


MAX232. MAX232I DUAL EIA-232 DRIVERS/RECEIVERS

SLLS:-7l-FESRbA=< r 133=1 - F.E .'!SEI> OCTC3ER-302

Meet or Exceed TIA/EIA-232-F and ITU Recommendation V.28

Operate With Single 5-V Power Supply

Operate Up to 120 kbit's

Two Drivers and Two Receivers

• ±30-V Input Levels

• Low Supply Current . . . 8 mA Typical

• Designed to be Interchangeable With Maxim MAX232

• ESD Protection Exceeds JESD 22 - 2000-V Human-Body

Model (A114-A)

• Applications

TIA/EIA-232-F

Battery-Powered Systems

Terminals

Modems

Computers

description/ordering information

The MAX232 is a dual driver/receiver that includes a capaotive voltage generator to supply EIA-232 voltage levels from a single 5-V supply. Each receiver

converts EIA-232 inputs to 5-V TTl/CMOS levels. These receivers have a typical threshold of 1.3 V and a typical hysteresis of 0.5 V, and can accept

±30-V inputs. Each driver converts TTUCMOS input levels into EIA-232 levels The driver, receiver, and voltage-generator functions are available as cells in

the Texas Instruments LinASIC" library.

6 ] yCC •5 ]

GND '4 ] T10UT

• I ]

R1IN ]RIOUT ]T

1IN ] T2IN

? ] R20UT

PACKAGEtORDERABLE PART NUMBERTOP-SIDE MARKINGTC to 70"C-C P (NiT.r-tVAX232NMAX2.32NSOIC !D!Tite■VA.X232DMAX232

Tape and re*:VAX232DR

SOIC (DW)T.i:eVAX232QvYMAX232

Tape and reelVAX232DW3

SOP i.NS)Tape and reei■VAX232NSRMA.X232-4CPC tc 35XTjbeVAX232INMAX222INSOIC (D)TjfceMAX232iDMAX232I

Tape and reejVAX232 DR

SOIC I DW ITubeVAX232IDVVHAX232-

Tape and rse';,'AX2 32 2WR

ORDERING INFORMATION

guidelines are available atwiwwJ.com/ttl3ackage.

*al dais synljon-ation, and PCB design

http://atwiwwJ.com/ttl3ackage

Function Table:

EACH INPUT OUTPUT

TIN TOUTL HH L

H = high level. L = Sow level

EACH RECEIVER

INPUT OUTPUTRIN ROUTL HH L

H = high 1 evek L = sowlevel

logic diagram (positive logic)


T1IN

T2IN

R10UT

R20UT

11

10

12

[>> [>

<<r

14

13

T10UT

T20IJT

R1IN

R2IN


absolute maximum rat ings over operat ing free-a ir temperature range (unless otherwise noted)t

Input supply voltage range. Vcc (see Note I)................................................. - ■ ......................... -0.3 V to 6 VPositive output supply voltage range. Vg+.............................................................................................. Vcc - 0.3 V to 15 VNegative output supply voltage range V 'g_ ............................. ....................... .................-0.3 V to-15 VInput voltage range, V|: Dr iver ...................................................................................................-0.3 V to V'cc + 0 .3 V

Receiver ..............................................................................................................................+30 VOutput voltage range, V0: T iOUT, T20UT ................................................................................ Vs_- 0.3 V to Vg+ <• 0.3 V

R10UT. R20UT ........................................................................... -0.3 V to Vcc + 0.3 VShort-circuit duration: T10UT. T20UT.........................................................................................................................^UnlimitedPackage thermal impedance, ftj^ (see Note 2): D package ......................................................................................... 73XAV

DW package .................................................................... 57"CAVN package ...........................................................................e7°C/WNS package .........................................................................64'C/W

Lead temperature 1.6 mm (1/16 inch) from case for 10 seconds .................................................................................. 2QQ'JC

Storage temperature range, Tstq.................................................................................................................. -65°C to 150:C

REFERENCE

1) www.google.com

2) www.redcircuits.com

3) www.efy.com

4) ELECTRONICS FOR YOU MAGAZINE

http://www.efy.com/

http://www.redcircuits.com/

http://www.google.com/

files.spogel.comfiles.spogel.com/projectsqa/qa_00513--gsm_based... · web viewthese two pins are...

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