Z90251 Datasheet, PDF (67/97 Pages) Zilog, Inc. – eZVision 200 Television Controllers with OSD

Z90255 ROM and Z90251 OTP
32 KB Television Controller with OSD
59
Bit/
Field
P27
P26
P25
P24
P23
P22
P21
P20
Bit
Position
7
6
5
4
3
2
1
0
R/W Value Description
R
Data input on P27
W
Data Output on P27
R
Data input on P26
W
Data Output on P26
R
Data input on P25
W
Data Output on P25
R
Data input on P24
W
Data Output on P24
R
Data input on P23
W
Data Output on P23
R
Data input on P22
W
Data Output on P22
R
Data input on P21
W
Data Output on P21
R
Data input on P20
W
Data Output on P20
7.1 Port 4 Pin-Out Selection Register
Bits 5,4,3, and 2 control the configuration of multiplexed pins 20, 19, 18, and
17. If a bit is set to 0, the pin functions as a PWM output port. If a bit is set to 1, the
pin functions as a programmable regular input/output port. See Table 42. This
value is the default following a Power-On Reset.
Table 42 Port 4 Pin-Out Selection Register 08h: Bank C (PIN_SLT)
Bit
7
6
5
4
3
2
1
0
R/W
Reset
R/W R/W R/W R/W R/W R/W R/W R/W
x
x
1
1
1
1
x
x
Note: R = Read W = Write X = Indeterminate
PS001301-0800