Z86C83 Datasheet, PDF (26/46 Pages) Zilog, Inc. – Z8 MCU MICROCONTROLLERS

Z86C83/C84
Z8^® MCU Microcontrollers
Interrupts. The Z8 has six different interrupts from six
different sources. These interrupts are maskable,
prioritized (Figure 20) and the six sources are divided as
follows: four sources are claimed by Port 3 lines P33-P30,
and two in counter/timers (Table 10). The Interrupt Mask
Register globally or individually enables or disables the six
interrupt requests.
When more than one interrupt is pending, priorities are
resolved by a programmable priority encoder that is
controlled by the Interrupt Priority register. An interrupt
machine cycle is activated when an interrupt request is
granted. This action disables all subsequent interrupts,
saves the Program Counter and Status Flags, and then
branches to the program memory vector location reserved
for that interrupt.
IRQ0 IRQ2
IRQ1, 3, 4, 5
Interrupt
Edge
Select
IRQ (D6, D7)
IRQ
Name
IRQ0
IRQ1,
IRQ2
IRQ3
IRQ4
IRQ5
26
Interrupt
Request
IMR
6
Global
Interrupt
Enable
IPR
PRIORITY
LOGIC
Vector Select
Figure 20. Interrupt Block Diagram
Table 10. Interrupt Types, Sources, and Vectors
Source
/DAV0, IRQ0
IRQ1
/DAV2, IRQ2, T_IN
IRQ3
T0
T1
Vector Location
0, 1
2, 3
4, 5
6, 7
8, 9
10, 11
Comments
External (P32), Rise/ Fall Edge Triggered
External (P33), Fall Edge Triggered
External (P31), Rise /Fall Edge Triggered
By User Software
Internal
Internal
DS96DZ80203