Z380 Datasheet, PDF (35/115 Pages) Zilog, Inc. – MICROPROCESSOR

ZILOG
MICROPROCESSOR
I/O Heartbeat Cycle
The Z380 MPU is capable of generating an I/O heartbeat
cycle on the I/O bus in response to an I/O write to an on-
chip control register. This cycle is most useful with Z80
family peripherals, where some members require a trans-
action that looks like a Z80 CPU instruction fetch to perform
certain interrupt functions (Figure 17).
IOCLK
ADDRESS
DATA
/WAIT
/MI
All Zeros
/IORQ
/IORD
/IOWR
/ INTAK
Figure 17. I/O Heartbeat Cycle
PS010001-0301