SH7144_08 Datasheet, PDF (680/930 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series

18. I/O Ports
18.1.1 Register Descriptions
Port A is a 16-bit input/output port in the SH7144; a 24-bit input/output port in the SH7145. Port
A has the following registers. For details on register addresses and register states during each
processing, refer to section 25, List of Registers.
• Port A data register H (PADRH)
• Port A data register L (PADRL)
18.1.2 Port A Data Registers H and L (PADRH and PADRL)
The port A data registers H and L (PADRH and PADRL) are 16-bit readable/writable registers
that store port A data. Bits PA15DR to PA0DR correspond to pins PA15 to PA0 (multiplexed
functions omitted here) in the SH7144. Bits PA23DR to PA0DR correspond to pins PA23 to PA0
(multiplexed functions omitted here) in the SH7145.
When a pin functions is a general output, if a value is written to PADRH or PADRL, that value is
output directly from the pin, and if PADRH or PADRL is read, the register value is returned
directly regardless of the pin state.
When a pin functions is a general input, if PADRH or PADRL is read, the pin state, not the
register value, is returned directly. If a value is written to PADRH or PADRL, although that value
is written into PADRH or PADRL, it does not affect the pin state. Table 18.1 summarizes port A
data register L read/write operations.
Rev.4.00 Mar. 27, 2008 Page 636 of 882
REJ09B0108-0400