Help with zilog Z80!!!

Discussion in 'Embedded Systems and Microcontrollers' started by fog76, Dec 4, 2012.

  1. fog76

    Thread Starter New Member

    Dec 4, 2012
    Hi guys, I need a little help!

    I have to make a circuit that when detects a low signal on IOREQ puts the processor in WAIT mode (low signal on WAIT pin).

    To generate the IOREQ signal i use this code:

    out ($1000), A

    My question is this: when my circuit puts the Z80 in wait, program counter
    will be the first or after the "nop" instruction? And after the CPU has detected the WAIT signal, what kind of values ​​will find on the data and address bus?

    Z80 run at 4 Mhz, my circuit use an Atmega8 at 16 Mhz that poll Z80's IOREQ value.

    Thank you all,