microprocessor and microcontroller lec2
TRANSCRIPT
Description
• ALU– This section performs various functions on Data– ALU can do Aromatic and Logical operations
• Register Array– This section consists of Registers used to store data during
program execution and to store data – The registers are B, C, D, E, H, L,
• Control Unit– This section provides timing and control signals for all the
operations in the microcomputer– This control the flow of data between microprocessor and
peripheral and memory
Memory
• Memory stores data and instructions and provide the information when needed
• Memory consists of ROM and RAM
• ROM Read Only Memory(Store Monitor program or Operating system)
• RAM Random Access Memory(User Memory)
• To execute the program microprocessor reads instructions from memory and performs the computing operations on it in ALU and transfer the data to Output or store the results in Memory
I/O
• It communicates with outside world
• I/O is Input Output it is also known as peripherals
• Input devices transfer data or instruction from outside world to the microprocessor
• Output devices transfer data from microprocessor to outside world
System Bus
• It communication path between microprocessor and peripherals.
• It is a group of wires which carries bits from and to microprocessor.
• Microprocessor communicate with only one peripheral at a time .
• The time signals are provided by control unit of the processor.
Registers of 8085
Data Bus Address Bus
Accumulator
L (8 bits register)H (8 bits register)
B (8 bits register)
D (8 bits register) E (8 bits register)
C (8 bits register)
Flag Register
Stack Pointer (16 bits)
Program Counter (16 bits)
Registers
• 8085 have six multipurpose 8 bits registers namely B, C, D, E, H,L.
• Accumulator is an 8 bit register it is part of ALU.
• It is used to store 8 bit data to perform arithmetic and logic operations.
• It is also identified as register A.
Flags
• ALU also include five flip flops.
• These are set or rested according to the results in the accumulator.
• These flip flops are showing that whether the data is zero(Z) ,Negative (S), Auxilary Carry or barrow (AC), Carry or barrow (C), Number of one in result (P).
S Z X A X P X C
Program counter and Stack pointer
• These are 16 bits registers used to hold memory addresses.
• Program counter is used to sequence the execution of instructions
• Stack pointer is used as memory pointer.
• It points to the memory location in R/W memory.