On 22/04/2016 3:06 AM, Eric Smith wrote:
A friend building a Z80 system asked me about whether the Z80 /WAIT
signal has any effect during machine cycles that aren't
memory/IO/intack cycles (i.e., neither /MREQ and /IORQ asserted). The
user manual only describes the use of /WAIT for adding wait states,
so I expect it probably only affects mem/IO/intack cycles, but I
can't find anything definitive in the user manual.
I'm hoping someone can save me the time of hooking up a logic
analyzer and running the experiment.
Thanks! Eric
http://kaput.homeunix.org/~thrashbarg/z80.pdf
Looking at this Z80 datasheet (page 20 of the PDF) the timing diagrams
say the /WAIT signal is sampled on the falling edge of clock state T2.
If it is active, additional cycles are introdced between T2 and T3. This
only occurs on op-code fetch, memory reference, input-output and
interrupt acknowledge cycles.
Alexis.
