8085

8085 Addressing modes?

1. Immediate addressing. eg. MVI A, 12H 2. Register addressing. eg. MOV B, C 3. Direct addressing. eg. IN 00H or OUT 01H 4. Indirect addressing. 5. Implicit addressing eg. CMA

Special Purpose registers in 8085?

1. Register A(Accumulator) 2. Flag Register(Program status word) 3. Instruction register 4. Program Counter(PC) 5. Stack Pointer(SP)

Interrupts in 8085?

5 hardware interrupts - TRAP, RST 7.5, RST 6.5, RST 5.5, INTR (written from highest priority to lowest) 8085 can't ignore TRAP interupt. 8 software interrupts - RST 0, RST 1, RST 2, RST 3, RST 4, RST 5, RST 6, RST 7. Vectore & non vector interrupts

About 8085?

8 bit microprocessor, design based on intel 8080. Designed using nmos tech. "5" in th model represents +5V power supply it needed to run. 8 bit data bus, 16 bit address bus, 64K bytes of memory, 8 bit ALU, 8 bit accumulator, 16 bit program counter, 16 bit stack pointer, works at 5Mhz clock frequency. 40 pins in chips out of which 27 are output pins. Lower order address bus is multiplexed with data bus to minimize overall size.

Flag Register in 8085?

8-bit register, in which five of the bits carry significant information in the form of flags: S(Sign flag), Z(Zero flag), AC (Auxiliary Carry flag), P(Parity flag),and CY(Carry flag)

ALU?

Arithmetic and Logic Unit - does all mathematical calculations and makes all logical decisions. addition, subtraction, multiplication, division, AND, OR, EX-OR, NOT, increment, decrement, left shift, right shift, clear etc.

Data Bus

Bus is bidirectional. Size of the data bus determines what arithmetic can be done. Data bus also carries instructions from memory to the microprocessor.

Operations of Microprocessor?

Four operations: Memory Read: Reads data (or instruction) from memory. Memory Write: Writes data (or instruction) into memory. I/O Read: Accepts data from input device. I/O Write: Sends data to output device.

how does 8085 processor looks like?

Just check it out what you've been reading about :)

Memory size formula?

Memory size = 2^A x D where, A denotes the address lines, and D denotes the data lines.

general purpose registers in 8085?

Six, B, C, D, E, H & L to store 8 bit data. Also, can be combined in pairs BC DE HL to perform 16 bit operations.

Arithmetic instructions

These instructions are used to perform arithmetic operations such as addition, subtraction, increment or decrement of the content of a register or memory. Examples: ADD, ADC, ADI, DAD, SUB, INR, DCR, etc.

Branching Instructions

These instructions are used to perform conditional and unconditional jump, subroutine call and return, and restart. Examples: JZ, JNZ, JC, JNC, JP, JM, JPE, JPO, CALL, RET, RST, etc.

Logical Instructions

These instructions are used to perform logical operations such as AND, OR, compare, rotate etc. Examples: ANA, ANI, ORA, ORI, XRA, CMA, CMC , STC, CMP, RLC, RAL, RAR, etc

Data transfer instructions

These instructions are used to transfer data from one register to another register, from memory to register or register to memory. MOV, MVI, LXI, LDA, STA

Machine Control Instructions

These instructions control machine functions such as Halt, Interrupt, or do nothing. Example: PUSH, POP, HLT, XTHL, NOP, EI, DI, etc.

Address bus?

bus consist of 16 wires, Address bus is unidirectional, i.e., numbers only sent from microprocessor to memory.

appications of 8085?

washing machine, microwaves, mobile phones, satellite, radar, flights