Rev. 1.0, 02/00, page 208 of 1141
MOS Pull-Up Select Register 3 (PUR3)
0
0
1
0
R/W
2
0
R/W
3
0
4
0
R/W
0
R/W
5
0
7
0
R/W
R/W
R/W
R/W
6
PUR34
PUR33
PUR32
PUR31
PUR30
PUR37
PUR36
PUR35
Bit :
Initial value :
R/W :
MOS pull-up selector register 3 (PUR3) controls the ON and OFF of the MOS pull-up transistor
of port 3. Only the pin whose corresponding bit of PCR3 was set to 0 (input) becomes valid. If
the corresponding bit of PCR3 is set to 1 (output), the corresponding bit of PUR3 becomes invalid
and the MOS pull-up transistor is turned off.
PUR3 is an 8-bit read/write enable register. When reset, PUR3 is initialized to H'00.
Bits 7 to 0
P37 to P30 MOS Pull-Up Control (PUR37 to PUR30)
Bit n
PCR3n
Description
0
The P3n pin has no MOS pull-up transistor
(Initial value)
1
The P3n pin has a MOS pull-up transistor
(n = 7 to 0)
10.5.3
Pin Functions
This section describes the port 3 pin functions and their selection methods.
P37/TMO: P37/TMO is switched as shown below according to the PMR37 bit in PMR3 and the
PCR37 bit in PCR3.
PMR37
PCR37
Pin Function
0
P37 input pin
0
1
P37 output pin
1
*
TMO output pin
Note:
*
Don’t care