In this section we will see some advanced features of Zilog Z-80 Microprocessor. These features are basically compared to the Intel 8085 Microprocessor.
The features are listed below −
|Sr.No.||Features & Description|
In this Microprocessor there are 698 Opcodes of different lengths.
The instructions can be divided into four categories according to their lengths.
There are 202 of 1-byte instructions,
344 of 2-byte instruction
74 of 3-byte instruction
78 of 4-byte instruction
The instructions can also be divided into two parts according to the opcode length. In the instruction set, there are instructions with 1-byte opcode and 2-byte opcode.
The number of 1-byte opcode instruction is 252, and number of 2-byte opcode instruction is 446
|4||New addressing modes, compared to 8085|
Like 8085, it has different addressing modes, but here some additional addressing modes are also available. These addressing modes are,
Indexed Addressing Mode
Relative Addressing Mode
Bit Addressing Mode
|5||New Instructions, compared to 8085|
In 698 instructions, there are many instructions, which are different from the 8085. The instruction types are like these,
Different I/O instructions
Different Exchange Instructions
Decimal adjustment instructions after Addition and Subtraction
Different Shift and Rotate Instruction
Direct Memory Access type instruction
In Z-80 there are powerful interrupt structure compared to 8085 Microprocessor.