Z90251 ZILOG [Zilog, Inc.], Z90251 Datasheet - Page 77

• Manufacturer Part Number: Z90251
• Description: eZVision 200 Television Controllers with OSD
• Manufacturer: ZILOG [Zilog, Inc.]

Port 4 Pin-Out Selection Register
Bits 5, 4, 3, and 2 of the Port 4 Pin-Out Selection Register (Table 55) control the
configuration of multiplexed pins 20, 19, 18, and 17. If a bit is reset to 0, the pin
functions as a PWM output port. This value is the default following a Power-On
Reset. If a bit is set to 1, the pin functions as a programmable regular input/output
port.
Table 55 Port 4 Pin-Out Selection Register 08h: Bank C (PIN_SLT)
Bit/
Field
6-bit/14-bit PWM6
PWM 11 / P56
PWM 6* / P55
PWM 5 / P54
PWM 4 / P53
PWM 3 / P52
PWM 2 / P51
PWM 1 / P50
Note: PWM6 can be either 6- or 14-bit depending on the bit status in bit7.
Bit
R/W
Reset
Note: R = Read W = Write X = Indeterminate
R/W
7
x
Bit
Position
7
6
5
4
3
2
1
0
R/W
6
x
R/W
5
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
32 KB Television Controller with OSD
R/W
4
1
Value Description
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
R/W
3
1
Select 6-bit (POR)
Select 14-bit
Select PWM 11
Select P56 - POR
Select PWM 6
Select P55 - POR
Select PWM 5
Select P54 - POR
Select PWM 4
Select P53 - POR
Select PWM 3
Select P52 - POR
Select PWM 2
Select P51 - POR
Select PWM 1
Select P50 - POR
R/W
2
1
R/W
PS001301-0800
1
x
R/W
0
x
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