Write the number of memory cycles required to execute the following 8085 instructions (I) LDA 3000H (II) LXI D, F0F1H

Write the number of memory cycles required to execute the following 8085 instructions

1. LDA 3000H 
2. LXI D, F0F1H

Answer:

1. LDA 3000H :-

LDA means load accumulator. It basic use is to load content into an accumulator.

First it will fetch instruction from starting address.

Reading is done for next two memory address. 3000H is load into Temporary register WZ pair, 00 will be stored into the Z and 30 will be stored into W.

Finally WZ will latch and read value which is stored in a 3000h. Therefore, Move the content of 3000H into Acccumulator.

LDA 3000H:- Fetch, Read, Read, Read

2. LXI D,F0F1H:-

LXI means load register pair immediately.

First it will fetch instruction from starting address.

Reading is done for next two memory address. F0F1H is load into register DE pair, F1 will be stored into the E and F0 will be stored into D.

LXI D,F0F1H:- Fetch, Read, Read