z89138 ZiLOG Semiconductor, z89138 Datasheet - Page 26

• Manufacturer Part Number: z89138
• Description: Voice Processing Controllers
• Manufacturer: ZiLOG Semiconductor

PIN FUNCTIONS (Continued)
Z89138/Z89139
Voice Processing Controllers
Port 3 (P37-P31). Port 3 is a 7-bit, CMOS compatible port
with three fixed inputs (P33-P31) and four fixed outputs
(P37-P34). It is configured under software control for in-
put/output, counter/timers, interrupt, and port handshakes.
Pins P31, P32, and P33 are standard CMOS inputs; out-
puts are push-pull.
Two on-board comparators can process analog signals on
P31 and P32 with reference to the voltage on P33. The an-
alog function is enabled by programming bit 1 of the Port 3
Mode Register. Port 3, pin 3 is a falling edge interrupt in-
put. P31 and P32 are programmable as rising, falling or
both edge-triggered interrupts (IRQ register bits 6 and 7).
P33 is the comparator reference voltage input. Access to
counter/timer1 is made through P31 (T
Notes:
HS = Handshake Signals
D = DAV
R = RDY
26
P31
P32
P33
P34
P35
P36
P37
Pin
OUT
OUT
OUT
OUT
I/O
IN
IN
IN
CTC1
T
T
OUT
IN
IN
) and P36 (T
Table 5. Port 3 Pin Assignments
AN IN
AN1
AN2
REF
P R E L I M I N A R Y
OUT
).
IRQ2
IRQ0
IRQ1
Int.
Handshake lines for ports 0, 1, and 2 are available on P31
through P36.
Port 3 also provides the following control functions: hand-
shake for Ports 0, 1, and 2 (/DAV and RDY); three external
interrupt request signals (IRQ3-IRQ1); timer input and out-
put signals (T
Comparator Inputs. Port 3, pins P31 and P32 all have a
comparator front end. The comparator reference voltage,
pin P33, is common to both comparators. In analog mode,
P31 and P32 are the positive inputs to the comparators
and P33 is the reference voltage supplied to both compar-
ators. In digital mode, pin P33 can be used as a P33 reg-
ister input or IRQ1 source.
P0 HS
D/R
R/D
IN
and T
P1 HS
D/R
R/D
OUT
) (Figure 14).
P2 HS
D/R
R/D
DS97TAD0201
EXT
DM
Zilog