Z86E30/E31/E40
Z8 4K OTP Microcontroller
Zilog
Port 3 (P37-P30). Port 3 is an 8-bit, CMOS-compatible
port with four fixed inputs (P33-P30) and four fixed outputs
(P37-P34). These eight lines can be configured by soft-
ware for interrupt and handshake control functions. Port 3,
Pin 0 is Schmitt- triggered. P31, P32 and P33 are standard
CMOS inputs with single trip point (no Auto Latches) and
P34, P35, P36 and P37 are push-pull output lines. Low
EMI output buffers can be globally programmed by the
software. Two on-board comparators can process analog
signals on P31 and P32 with reference to the voltage on
P33. The analog function is enabled by setting the D1 of
Port 3 Mode Register (P3M). The comparator output can
be outputted from P34 and P37, respectively, by setting
PCON register Bit D0 to 1 state. For the interrupt function,
P30 and P33 are falling edge triggered interrupt inputs.
P31 and P32 can be programmed as falling, rising or both
edges triggered interrupt inputs (Figure 21). Access to
Note: P33-P30 differs from the Z86C30/C31/C40 in that
there is no clamping diode to V due to the EPROM high-
CC
voltage circuits. Exceeding the V maximum specification
IH
during standard operating mode may cause the device to
enter EPROM mode.
1
Counter/Timer 1 is made through P31 (T ) and P36
IN
(T
). Handshake lines for Port 0, Port 1, and Port 2 are
OUT
also available on Port 3 (Table 9).
DS97Z8X0500
P R E L I M I N A R Y
29
ZILOG [ ZILOG, INC. ]
