Nice Z80+ Operation Manual page 20

Memory Refresh
NOTE
If you use NICE in a system that requires continu-
ous access to the memory bus (such as a CRT
controller), you should expect an under run condi-
tion when NICE enters the QUIT mode.
When NICE is in the QUIT mode, the Z80 control lines are cycled so that systems
containing dynamic RAM will not lose data. The Refresh function is always enabled
following power up.
NOTE
If
the target system does not have dynamic RAM,
it is a good idea to disable the Refresh function.
This allows NICE to operate 2.5 percent faster.
Memory Requests
When NICE is in the GO mode, memory requests are identical to Z80 memory
requests. When NICE is in the QUIT mode, however, requests are extended.
1/0 Requests
NOTE
The lines which control memory access with NICE
in the target system are active for a longer period
of time than they would be ordinarily. Therefore,
during a memory read, be sure that data from the
target system RAM remains valid for the entire
period as indicated by the Z80 control lines.
When NICE is in the QUIT mode,
1/0
control signals are extended beyond ordinary
duration. As with memory requests, then,
be
sure that
1/0
read data remains vaHd
for the duration as indicated by the Z80 control lines.
14.