Z90251 ZILOG [Zilog, Inc.], Z90251 Datasheet - Page 65

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

7
Input/Output Ports
There are 20 input/output (I/O) ports. In addition, seven pulse-width modulators
(PWM), PWM1 through PWM6, and PWM11, can be configured as regular output
ports. The maximum number of I/O ports available is 27. Please refer to the port
bank and number carefully for exact addressing and access. See Table 39
through Table 49.
Table 39 Port configuration Register 00h: Bank F (PCON)
Ports 2, 4, and 6 can be set for Standard or Low EMI. The Low EMI option
can also be selected for the microcontroller oscillator or OSD oscillator. Standard
(1) is the High setting. Following Power-On Reset, Bits 1, 2, 5, 6, 7 each
has a value of 1.
Bit
R/W
Reset
Note: R = Read W = Write X = Indeterminate
Bit/
Field
Low EMI Z8
Oscillator
Low EMI Port 6
Low EMI Port 2
Reserved
Low EMI Port 4 and
PWMs
Low EMI OSD
Oscillator
Reserved
R/W
7
1
Bit
Position
7
6
5
4, 3
2
1
0
R/W
6
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
W
R
5
1
Value
32 KB Television Controller with OSD
R/W
4
1
0
1
0
1
0
1
0
1
0
1
Description
Low EMI Noise
Standard-POR
Low EMI Noise
Standard-POR
Low EMI Noise
Standard-POR
Return 1
Write 1s
Low EMI Noise
Standard-POR
Low EMI Noise
Standard-POR
Return Unknown
No Effect
R/W
3
1
R/W
2
1
R/W
PS001301-0800
1
1
R/W
0
0
57