Z80 Datasheet, PDF (80/330 Pages) Zilog, Inc. – Z80 CPU PERIPHERALS

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Table 10. Events and Actions
Event
End-of-Block
Byte Match (Compare)
Pulse-control byte matches lower part of
byte counter
READY Inactive
READY Active
RETI Instruction (return from interrupt
instruction from the Z80 CPU)
Actions Possible When Event
Occurs
1. Release Bus
2. Interrupt CPU
3. Auto Restart
1. Release Bus
2. Interrupt CPU
3. Continue
1. Generate Pulse
1. Release Bus
2. Suspend (continuous mode
only)
1. Request Bus
2. Interrupt CPU
1. Request Bus
PIN DESCRIPTION
The following pin descriptions detail the function of the Z80 DMA external
pins as illustrated in Figure 25 through Figure 28.
A15-A0
System Address Bus (output, tristate). Addresses generated by the DMA are
sent to both source and destination ports, either of which may be main
memory or I/O peripherals.
UM008101-0601
Direct Memory Access