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The Intel (“eighty-eighty-five”) is an 8-bit microprocessor produced by Intel and introduced in It is a software-binary compatible with the more-famous. Microprocessor: It is a programmable electronics chip (Integrated Circuit ( IC)). A single IC has computing and decision making capabilities similar to. In addition to the microprocessor, a personal computer has a keyboard for The AS/ uses the PowerPC microprocessor with its reduced instruction set.

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Sorensen, Villy January The contents of the H register provide the high-order address and the contents of the L register provide the low-order address. All buses are tri-stated and a Hold Acknowledge signal is sent out.

8085 Data-transfer Instructions

S0 and S1 are status signals which provides different status and functions depending on their status. READY is used by the microprocessor to check whether a peripheral is ready to accept or transfer data.

MOV A, [[]] Implicit addressing: These instructions are used to transfer data from one register to another register, from memory to register or register to memory. In the previous articles we saw about the architecture of microprocessor. Comments Write a comment. In other projects Wikimedia Commons. The content stored in the stack pointer and program counter is loaded into the address buffer and address-data buffer to communicate with the CPU. Some of them are followed by one or two bytes of data, which can be an immediate operand, a memory address, or a port number.


The Address bus consists of 16 wires. Introduction In the previous articles we saw about the architecture of microprocessor.

As the name suggests micrpprocessor controls the interrupts during a process. A 1-byte instruction includes the opcode and operand in the same mictoprocessor.

Week 7 Aug 20 35 upvotes. Trainer kits composed of a printed circuit board,and supporting hardware are offered by various companies. This distinguishes whether the address is for memory or IO. These instructions use bit operands and include indirect loading and storing of a word, a subtraction, a shift, a rotate, and offset operations. Although PIO is not necessarily slower than DMA, it does consume more processor cycles and can be detrimental in a multi-processing environment.

INTR is an interrupt request signal. The stack pointer is incremented by 1 and the microproceszor of that memory location are copied to the high-order register B, D, H, A of the operand. Write assembly program for multiplying two 8 bit numbers.

This is provided by CLK pin.

Pin Diagram and Pin description of Microprocessor

Steps involved in the mode of DMA midroprocessor are as follows. Effective address is calculated by the processor and the contents of the address is used to form a second address. Decoder then takes instruction and decodes or interprets the instruction. The instruction loads the contents of the H and L registers into the stack pointer register.


The uses approximately 6, transistors. It controls data flow between CPU and peripherals including memory. That is, an operation is performed when the signal goes low.

The ALU performs the following arithmetic and logical operations. In a three byte instruction, the first byte specifies the opcode and the following two bytes specify the bit address.

This pin resets the program counter to 0 and resets interrupt enable and HLDA flip-flops. Output the data from the accumulator to a port with 8bit address. Which indicate that the selected IO or Memory device is to be read and data is available on the data bus. Used to accept data from outside devices to store in the accumulator or send the data stored in the accumulator to the outside device.

More complex operations and other arithmetic operations must be implemented in software. A NOP “no operation” instruction exists, but does not modify any of the registers or flags.

So the first clock cycle means the first transition of pulse from 0volts to 5 volts and then back to 0 volts. The contents of the microproocessor port designated in the operand are read and loaded into the accumulator. Decoded instruction then passed to next stage.