Why 8085 microprocessor is called 8085

They are less important than the accumulator. They are used to store data temporarily during the execution of the program. The following features enable microprocessor to be a versatile component in an instrumentation system.

The stack pointer always contains a memory address the location of the top of the stack. The program counter always contains a memory address the location of the next machine instruction to fetch. So, both the program counter and the stack pointer must be 16 bits wide. PUSH then places the operand on the new top of stack, which is pointed to by the stack pointer. The is an 8-bit microprocessor.

It was produced by Intel and first introduced in The is enhanced version of microprocessor. It is bit processor…. If there is a carry from addition or a borrow from subtraction or comparison, the carry flag CS is set to 1, otherwise 0. The zero status flag Z is set to 1 if the result of an arithmetic or logical operation is zero.

For non-zero result it is set to 0. The sign status flag is set to 1 if the most significant bit of the result of an arithmetic or logical operation is 1 otherwise 0. The parity status flag is set to 1 when result of the operation contains even number of 1's. It is set to zero when there is odd number of 1's. The auxiliary carry status flag holds carry out of bit 3 to 4 resulting from the execution of an arithmetic operation. Figure 3 shows the status flags for ADD operation.

Take an example of the instruction ADD B. The execution of the instruction ADD B will add the content of the register B to the contents of the accumulator. Suppose the contents of the accumulator and register B are C. B and ES respectively. Now C. B and ES are added and the result is 01, B4. As the accumulator is an 8-bit register B4 remains in the accumulator and there is a carry.

The various status flags are shown in figure 2. In figure 2 Five bits indicate the five status flags and three bits are undefined. PSW and the accumulator are treated as a bit unit for stack operations. The Intel is an 8-bit microprocessor. Its data bus is 8-bit wide and hence, 8 bits of data can be transmitted in parallel from or to the microprocessor. The Intel requires a bits. The 8 most significant bits of the address are transmitted by the address bus, Pins A 8 , to A At a particular moment it transmits either data or address.

Thus the AD-bus operates in time shared mode. This technique is known as multiplexing. Thus the effective width of the address is latched so that the complete bit address remains available for further operation. The 8-bit AD-bus now becomes free, and it is available for data transmission 2 16 i. Each memory location contains 1 byte of data. The timing and control unit generates timing signals for the execution of instruction and control of peripheral devices.

The organization of a microprocessor and types of registers differ from processor to processor. The timing used for the execution of instructions and control of peripherals are different for different microprocessors. The selection of a suitable microprocessor for a particular application is a tough task for an engineer. The knowledge of the organization and timing and control system helps an engineer in the selection of a microprocessor.

The design and cost of a processor also depends on the timing structure and register organization. For the execution of an instruction a microprocessor fetches the instruction from the memory and executes it. The time taken for the execution of an instruction is called instruction cycle IC. Your technical expertise would be needed to create quality articles and content on this site and hence contribute to this growing global community of technical enthusiast.

Create quality content and get recognized! Our Works! Dear Shyam, There must be some reason behind other series of microprocessors which i dont know. What i shared with you is true for Since every manufacturer choose their product name on a separate basis so it is quite difficult to keep track of nomenclature guidlines of each and every products. However we can keep abrest with few important names. Author:arbelectbit yahoo. Dear Shyam, THis absolutely correct and excellent answer.