SH7101 Datasheet, PDF (408/486 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

14. I/O Ports
14.2 Port B
Port B is an input/output port with the four pins shown in figure 14.2.
Port B
PB5 (I/O) / IRQ3 (input) / POE3 (input)
PB4 (I/O) / IRQ2 (input) / POE2 (input)
PB3 (I/O) / IRQ1 (input) / POE1 (input)
PB2 (I/O) / IRQ0 (input) / POE0 (input)
Figure 14.2 Port B
14.2.1 Register Description
Port B is a 4-bit input/output port. Port B has the following register. For details on register
addresses and register states during each processing, refer to section 18, List of Registers.
• Port B data register (PBDR)
14.2.2 Port B Data Register (PBDR)
PBDR is a 16-bit readable/writable register that stores port B data. Bits PB5DR to PB2DR
correspond to pins PB5 to PB2 (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 14.2 summarizes port B data register read/write operations.
Rev.2.00 Sep. 27, 2007 Page 374 of 448
REJ09B0394-0200