119
Section 8 I/O Ports
8.1
Overview
The H8/3637 Series is provided with six 8-bit I/O ports, one 7-bit I/O port, one 4-bit I/O port, one
2-bit I/O port, one 4-bit input-only port, and one 1-bit input-only port. Table 8.1 indicates the
functions of each port.
Each port has of a port control register (PCR) that controls input and output, and a port data
register (PDR) for storing output data. Input or output can be controlled by individual bits.
See 2.9.2, Notes on Bit Manipulation, for information on executing bit-manipulation instructions
to write data in PCR or PDR.
Block diagrams of each port are given in Appendix C, I/O Port Block Diagrams.