Z86L825 Datasheet, PDF (24/79 Pages) Zilog, Inc. – 20-Pin Low-Voltage IR Microcontrollers

Z86L825/826/827
20-Pin Low-Voltage IR Microcontrollers
17
edge-triggered interrupts (IRQ register bits 6 and 7). P33 is the comparator refer-
ence voltage input. Access to the counter/timer edge-detection circuit is through
P31 or P20 (see “CTR1 Register” on page 38). Other edge-detect and IRQ modes
are described in Table 8.
Table 8. Pin Assignments
Pin
I/O
C/T
P31
IN
IN
P32
IN
P33
IN
P34
OUT
T8
P36
OUT
T8/16
P20
I/O
IN
Comp.
AN1
AN2
RF2
AO1
Int.
IRQ2
IRQ0
IRQ1
Port 3 also provides output for the counter/timers and the AND/OR logic. Control
is performed by programming bits D5–D4 of CTR1 and bit 0 of CTR0.
Comparator Inputs
In analog mode, P32 and P33 have a comparator front end. The comparator refer-
ence is supplied to P33. In this mode, the P33 internal data latch and its corre-
sponding IRQ1 are diverted to the SMR sources (excluding P31, P32, and P33)
as indicated in Figure 8. In digital mode, P33 is used as D3 of the Port 3 input reg-
ister, which then generates IRQ1.
Note: Comparators are powered down by entering STOP Mode. For
P31–P33 to be used in a Stop-Mode Recovery source, these
inputs must be placed into digital mode.
PS008808-1203
PRELIMINARY