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8. I/O Ports
Section 8 I/O Ports
8.1
Overview
The H8/3857 Group is provided with four 8-bit I/O ports, one 3-bit I/O port, one 8-bit input-only
port, and one 1-bit input-only port. The H8/3854 Group is provided with two 8-bit I/O ports, one
3-bit I/O port, one 5-bit I/O port, one 4-bit input-only port, and one 1-bit input-only port. In
addition, both group have an I/O port capable of interfacing with the on-chip LCD controller.
H8/3857 Group port functions are listed in table 8.1 (a), and H8/3854 Group port functions in
table 8.1 (b).
Each port has 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 assigned to individual bits. See section 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.
Rev.3.00 Jul. 19, 2007 page 169 of 532
REJ09B0397-0300
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