SH7144 Datasheet, PDF (597/773 Pages) Renesas Technology Corp – Hitachi SuperH RISC engine

18.2 Port B
Port B is an input/output port with the 10 pins shown in figure 18.3.
Port B
PB9 (I/O) /
(input) / A21 (output) /
(input)
PB8 (I/O) /
(input) / A20 (output) /
(input)
PB7 (I/O) /
(input) / A19 (output) /
(input)
PB6 (I/O) /
(input) / A18 (output) /
(output)
PB5 (I/O) /
(input) /
(input)
PB4 (I/O) /
(input) /
(input)
PB3 (I/O) /
(input) /
(input) / SDA0 (I/O)
PB2 (I/O) /
(input) /
(input) / SCL0 (I/O)
PB1 (I/O) / A17 (output)
PB0 (I/O) / A16 (output)
Figure 18.3 Port B
18.2.1 Register Descriptions
Port B is a 10-bit input/output port. Port B has the following register. For details on register
addresses and register states during each processing, refer to section 25, List of Registers.
• Port B data register (PBDR)
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.
Rev. 2.0, 09/02, page 557 of 732