Z08617 NMOS Z8
®
8-B
IT
MCU
K
EYBOARD
C
ONTROLLER
8
Port 2
(P27-P20). Port 2 is an 8-bit, bit programmable, bi-
directional, NMOS compatible I/O port. These eight I/O
lines are configured under the software control program
for I/O. Port 2 can be programmed as bit-by-bit indepen-
dently, as input or output, or configured to provide open-
drain outputs (Figure 7). P26 and P27 have 2.4 Kohms
(
±
25%) pull-up resistors and are capable of sourcing
2.4 mA. P24 and P25 have 10.4 Kohms (
±
35%) pull-up
when configured as inputs.
Open-Drain
OUT
OEN
IN
Pad
Input
(a) Ports P20-P23
Port 2
(I/O)
Z8615
Open-Drain
OUT
OEN
IN
Pad
10.4 Kohms
Input
(b) Ports P24-P25
Open-Drain
OUT
OEN
IN
Pad
2.4 Kohms
Input
(c) Ports P26-P27
Figure 7. Port 2 Configuration