Instruction set need help

[vead]

I have question how to design Instruction set (just for paper work)

I chose 8 bit instruction with 8 instruction 4 for arithmetic operations and 4 for logic operation

1)what should be operand and opcode ?
2)what should I know before to design ?

 

[(*steve*)]

2)what should I know before to design ?

Your first step is to know how many instructions you can have with an 8 bit instruction length. (hint: it's not 8)

 

[BobK]

You really need to go back and learn something about microcontrollers before trying to design one.

Bob