Z86L78 Datasheet, PDF (39/59 Pages) Zilog, Inc. – IR/Low-Voltage Microcontroller

Zilog
Z86L78
IR/Low-Voltage Microcontroller
Table 3. Interrupt Types, Sources and Vectors
Name
IRQ0
IRQ1,
IRQ2
IRQ3
IRQ4
Source
IRQ0
IRQ1
/DAV2,
IRQ2, T_IN
T16
T8
Vector
Location
Comments
0, 1 External (P32),
Rising Falling Edge
Triggered
2, 3 External (P33),
Falling Edge
Triggered
4, 5 External (P31),
Rising Falling Edge
Triggered
6, 7 Internal
8, 9 Internal
Programming bits for the Interrupt Edge Select are located
in the IRQ Register (R250), bits D7 and D6. The configu-
ration is shown in Table 4.
1
Table 4. Interrupt Types, Sources, and Vectors
IRQ
D7
D6
0
0
0
1
1
0
1
1
Notes:
F = Falling Edge
R = Rising Edge
Interrupt Edge
IRQ2(P31)
F
F
R
R/F
IRQ0 (P32)
F
R
F
R/F
When more than one interrupt is pending, priorities are re-
solved by a programmable priority encoder controlled by
the Interrupt Priority register. An interrupt machine cycle is
activated when an interrupt request is granted. This dis-
ables all subsequent interrupts, saves the Program
Counter and Status Flags, and then branches to the pro-
gram memory vector location reserved for that interrupt.
All Z86L78 interrupts are vectored through locations in the
program memory. This memory location and the next byte
contain the 16-bit address of the interrupt service routine
for that particular interrupt request. To accommodate
polled interrupt systems, interrupt inputs are masked and
the Interrupt Request register is polled to determine which
of the interrupt requests need service.
Notes: In analog mode, the Stop-Mode Recovery sources
selected by the SMR register are connected to the IRQ1
input. Any of the Stop-Mode Recovery sources for SMR
(except P31,P32 and P33) can be used to generate IRQ1
(falling edge triggered).
An interrupt resulting from AN1 is mapped into IRQ2, and
an interrupt from AN2 is mapped into IRQ0. Interrupts
IRQ2 and IRQ0 may be rising, falling, or both edge trig-
gered, and are programmable by the user. The software
can poll to identify the state of the pin.
DS97LVO0701
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