Apangshu Das

8085 Microprocessor: Memory Read Cycle & Memory Write Cycle Bus Cycle A bus cycle is the time taken by the microprocessor to complete one operation, like reading or writing data. Each operation happens over a few machine cycles (timing periods), controlled by the clock signals (T-states). When the 8085 wants to read data from memory, […]

8085 Microprocessor: Opcode Fetch Cycle In the 8085 Microprocessor, the Opcode Fetch Cycle is the first and most essential part of the instruction execution process. It is the phase where the microprocessor fetches the operation code (opcode) of an instruction from memory to determine what operation needs to be performed. Every instruction execution in the

Timing Diagram of 8085 Microprocessor Concept of Instruction Cycle, Machine Cycle and T-State The 8085 microprocessor fetches the instruction from the address in the program counter, decodes it, and then executes it. If needed, it fetches extra data before finishing execution. Each instruction has two parts: the opcode, which is the command (like ADD), and

8085 Instruction Classification by Function The 8085 microprocessor works with a set of instructions called the instruction set. Each instruction tells the processor what kind of task it should perform. To make it easier to study, these instructions are grouped into categories based on their functionality. In the 8085 microprocessor, instructions are classified into five

8085 Instruction Classification by Length (1, 2 & 3 Bytes) In the 8085 microprocessor, every instruction is stored in memory in the form of bytes. A byte is simply 8 bits of data. Depending on how much information an instruction carries, the total length of an instruction can be 1 byte, 2 bytes, or 3

Addressing Modes of 8085 Microprocessor What are Addressing Modes? Different methods of instructing the microprocessor on where to locate the data it needs to work with are known as addressing modes. You may say “go to the blue house” or “go to house number 123” to guide someone to your house; both directions go to

Demultiplexing of Address and Data Bus in 8085 Microprocessor When we study the 8085 microprocessor, one of the first things to understand is how it uses its pins to carry information. The 8085 is designed in such a way that the lower 8 lines (pins) are used for two different purposes at different times. These

Bus Structure & Control Signals of 8085 Microprocessor (Part 2) The bus structure of the 8085 microprocessor is shown in Figure 1. It is divided into three categories: Address bus, Data bus, and Control bus. The Address bus and Data bus were discussed in Part 1, while this section focuses on the Control bus. Fig.

Bus Structure & Control Signals of 8085 Microprocessor (Part 1) Microprocessor (Part 1) The 8085 microprocessor uses a bus structure to connect its internal parts to external memory and peripheral devices. It is essential to know the bus architecture in order to understand how the microprocessor communicate and performs instructions. The bus structure of the

8085 Microprocessor Architecture The 8085 is called an 8-bit processor since its data length and data bus width is 8-bits. It has an addressing capability of 16 bits, that is, it can address 216 = 64 KB of memory (1 KB = 1024 bytes). 8085 microprocessors generally available in 40 pin IC package and uses