Datasheet

Section 8 I/O Ports
Rev. 8.00 Mar. 09, 2010 Page 240 of 658
REJ09B0042-0800
Port Data Register B (PDRB)
Bit
Read/Write
7
PB
7
R
6
PB
6
R
5
PB
5
R
4
PB
4
R
3
PB
R
0
PB
R
2
PB
R
1
PB
R
32 10
Reading PDRB always gives the pin states. However, if a port B pin is selected as an analog input
channel for the A/D converter by AMR bits CH3 to CH0, that pin reads 0 regardless of the input
voltage.
Port Mode Register B (PMRB)
Bit
Initial value
Read/Write
7
⎯
1
⎯
6
⎯
1
⎯
5
⎯
1
⎯
4
⎯
1
⎯
3
IRQ1
0
R/W
0
⎯
1
⎯
2
⎯
1
⎯
1
⎯
1
⎯
PMRB is an 8-bit read/write register controlling the selection of the PB
3
pin function. Upon reset,
PMRB is initialized to H'F7.
Bits 7 to 4 and 2 to 0—Reserved
Bits 7 to 4 and 2 to 0 are reserved; they are always read as 1 and cannot be modified.
Bit 3—PB
3
/AN
3
/IRQ
1
Pin Function Switch (IRQ1)
These bits select whether pin PB
3
/AN
3
/IRQ
1
is used as PB
3
/AN
3
or as IRQ
1
/TMIC.
Bit 3
IRQ1 Description
0 Functions as PB
3
/AN
3
input pin (initial value)
1 Functions as IRQ
1
/TMIC input pin
Note: Rising or falling edge sensing can be selected for the IRQ
1
/TMIC pin.
For TMIC pin setting information, see the Timer More Register C (TMC) description in section
9.3.2, Register Descriptions.