Z86L70 Datasheet, PDF (16/61 Pages) Zilog, Inc. – IR/Low-Voltage Microcontroller

Z86L70/71/75/C71
IR/Low-Voltage Microcontroller
Zilog
PIN FUNCTIONS (Continued)
Port 3 (P36-P31). Port 3 is a 6-bit, CMOS-compatible
three fixed input and three fixed output port. Port 3 consists
of three fixed input (P33-P31) and three fixed output (P36-
P34), and can be configured under software control for In-
put/Output, Interrupt, and output from the counter/timers.
P31, P32, and P33 are standard CMOS inputs; outputs are
push-pull, except for P34, P35 which have floating drain
capability (controlled by P3M, D0).
Two on-board comparators process analog signals on P31
and P32 with reference to the voltage on P33. The analog
function is enabled by programming the Port 3 Mode Reg-
ister (bit 1). P31 and P32 are programmable as rising, fall-
ing, or both edge triggered interrupts (IRQ register bits 6
and 7). Pref1 and P33 are the comparator reference volt-
age inputs. Access to the Counter Timer edge detection
circuit is through P31 or P20 (see CTR1 description).
Port 3 provides the following control functions: three exter-
nal interrupt request signals (IRQ2-IRQ0).
Port 3 also provides output for each of the counter/timers
and the AND/OR Logic. Control is performed by program-
ming bits D5-D4 of CTRI, bit 0 of CTR0 and bit 0 of CTR2.
Table 2. Pin Assignments
Pin
I/O
C/T Comp. Int.
Ext
P31
IN
IN
AN1 IRQ2
P32
IN
AN2 IRQ0
P33
IN
V_REF IRQ1
P34 OUT
T8
A01
DM
P35 OUT T16
P36 OUT T8/16
P20 I/O
IN
P34 OUT
P31
P33
+ ^Comp1
-
Counter/Timer
T8
P34 OUT
P34
PAD
CTR0
D0
0 Normal Control
1 8-bit Timer output active
P32 ₊
-
P33
Comp2
PCON
D0 ^{0 = P34 Standard Output*}
1 = P34 Comparator Output
* ^{Reset condition.}
Figure 10. Port 3 Configuration
1-16
PRELIMINARY
DS97LVO0500