Re: Z80 its refresh pin

[zwsdotcom@gmail.com]

On Mar 27, 12:43 pm, srk...@gmail.com wrote:

> before these to see if I can see it cycling trying to load at add
> 0x00. The Z80 is a new processor to me, so its a bit of a learning
> curve. Do you know exactly what the Z80 does when it comes out of
> reset?

I haven't had to debug it to this level; I actually never used DRAM in
a Z80 design. I was lazy :)

If you can't get past this problem I will bring a Z80 board into work
(my scope here has deeper memory than my home scopes) and capture A0,
A1, M1, RFSH triggering on rising edge of RESET, so maybe we can see
something of interest.

> replace the clock with something else. Its the only thing that seems
> to govern refresh. My current clock is not exactly a 50/50 duty cycle.

As long as you're not violating the rise/fall time ratings, this
wouldn't be the issue, I've clocked it off 25% duty cycle without
problems. The Z80 is a fully static processor.