Z8018x Family
MPU User Manual
282
Table 53. Request Acceptances in Each Operating Mode
Current Normal
Status Operation
(CPU mode
Interrupt
Acknowledge
Cycle
BUS
SYSTEM
STOP
Mode
and IOSTOP
Mode)
Refresh
WAIT State Cycle
RELEASE SLEEP
Request
DMA Cycle Mode
Mode
Internal
I/O
•
•
•
•
•
•
•
Not
acceptable
Interrupt
NMI
•
•
•
Not acceptable Acceptable
Acceptable
Return from
SYSTEM
STOP mode
to normal
Interrupt
DMA cycle
acknowledge
cycle precedes.
NMI is accepted
after executing
stops
operation
Note: * Not acceptable when DMA Request is in level-sense.
•: Same as above.
MC: Machine Cycle
REQUEST PRIORITY
The Z80180 features three types of requests.
.
Table 54. The Z80180 Types of Requests
Type 1
Type 2
Accepted in specified state
WAIT
Accepted in each machine cycle Refresh Request, DMA
Request, and Bus Request.
Interrupt Request
Type 3
Accepted in each instruction
Type 1, Type 2, and Type 3 requests priority as follows.
•
•
Highest priority Type 1 > Type 2 > Type 3 lowest priority
Each request priority in Type 2 is shown as follows. highest priority
Bus Req. > Refresh Req. > DMA Request lowest priority
UM005001-ZMP0400
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