HD64F7144F50V Datasheet, PDF (686/932 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

18. I/O Ports
18.2.2 Port B Data Register (PBDR)
The port B data register (PBDR) is a 16-bit readable/writable register that stores port B data. Bits
PB9DR to PB0DR correspond to pins PB9 to PB0 (multiplexed functions omitted here).
When a pin functions is a general output, if a value is written to PBDR, that value is output
directly from the pin, and if PBDR is read, the register value is returned directly regardless of the
pin state.
When a pin functions is a general input, if PBDR is read, the pin state, not the register value, is
returned directly. If a value is written to PBDR, although that value is written into PBDR, it does
not affect the pin state. Table 18.2 summarizes port B data register read/write operations.
Bit
15 to
10
Bit Name Initial Value R/W
—
All 0
R
9
PB9DR 0
R/W
8
PB8DR 0
R/W
7
PB7DR 0
R/W
6
PB6DR 0
R/W
5
PB5DR 0
R/W
4
PB4DR 0
R/W
3
PB3DR 0
R/W
2
PB2DR 0
R/W
1
PB1DR 0
R/W
0
PB0DR 0
R/W
Description
Reserved
These bits are always read as 0. The write value
should always be 0.
See table 18.2
Rev.4.00 Mar. 27, 2008 Page 640 of 882
REJ09B0108-0400