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Port Control Register 3 (PCR3)
Bit :
PCR37
Initial value :
R/W :
Port control register 3 (PCR3) controls the I/Os of pins P37 to P30 of port 3 in a unit of bit.
When PCR3 is set to 1, the corresponding P37 to P30 pins become output pins, and when it is set
to 0, they become input pins. When the relevant pin is set to a general I/O by PMR3, settings of
PCR3 and PDR3 become valid.
PCR3 is an 8-bit write-only register. When PCR3 is read, 1 is read. When reset, PCR3 is
initialized to H'00.
Bits 7 to 0 Pin 37 to P30 Pin Switching (PCR37 to PCR30)
Bit n
PCR3n
Description
0
The P3n pin functions as an input pin
1
The P3n pin functions as an output pin
Port Data Register 3 (PDR3)
Bit :
PDR37
Initial value :
R/W :
R/W
Port data register 3 (PDR3) stores the data for the pins P37 to P30 of port 3. When PCR3 is 1
(output), the PDR3 values are directly read if port 3 is read. Accordingly, the pin states are not
affected. When PCR3 is 0 (input), the pin states are read if port 3 is read.
PDR3 is an 8-bit read/write enable register. When reset, PDR3 is initialized to H'00.
7
6
PCR36
PCR35
0
0
W
W
7
6
PDR36
PDR35
0
0
R/W
R/W
5
4
PCR34
PCR33
0
0
W
W
5
4
PDR34
PDR33
0
0
R/W
R/W
3
2
PCR32
PCR31
0
0
W
W
3
2
PDR32
PDR31
0
0
R/W
R/W
Rev. 1.0, 02/00, page 207 of 1141
1
0
PCR30
0
0
W
W
(Initial value)
(n = 7 to 0)
1
0
PDR30
0
0
R/W
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