Datasheet

Section 9 I/O Ports
Rev. 3.00 Sep. 10, 2007 Page 161 of 528
REJ09B0216-0300
9.8 Port B
Port B is an input port also functioning as an A/D converter analog input pin. Each pin of the port
B is shown in figure 9.8.
PB7/AN7/ExtU
PB6/AN6/ExtD
PB5/AN5
PB4/AN4
PB3/AN3
PB2/AN2
PB1/AN1
PB0/AN0
Port B
Figure 9.8 Port B Pin Configuration
Port B has the following register.
• Port data register B (PDRB)
9.8.1 Port Data Register B (PDRB)
PDRB is a general input-only port data register of port B.
Bit Bit Name
Initial
Value
R/W Description
7
6
5
4
3
2
1
0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0








R
R
R
R
R
R
R
R
The input value of each pin is read by reading this
register.
However, if a port B pin is designated as an analog input
channel by ADCSR in the A/D converter or as an external
comparison voltage input pin by LVDCR in the low-
voltage detection circuit, the corresponding bit is read
as 0.