I/O Ports; Overview - Hitachi H8/3048 Hardware Manual

Section 9 I/O Ports
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9.1 Overview

The H8/3048 Series has 10 input/output ports (ports 1, 2, 3, 4, 5, 6, 8, 9, A, and B) and one input
port (port 7). Table 9-1 summarizes the port functions. The pins in each port are multiplexed as
shown in table 9-1.
Each port has a data direction register (DDR) for selecting input or output, and a data register
(DR) for storing output data. In addition to these registers, ports 2, 4, and 5 have an input pull-up
MOS control register (PCR) for switching input pull-up MOS transistors on and off.
Ports 1 to 6 and port 8 can drive one TTL load and a 90-pF capacitive load. Ports 9, A, and B can
drive one TTL load and a 30-pF capacitive load. Ports 1 to 6 and 8 to B can drive a darlington pair.
Ports 1, 2, 5, and B can drive LEDs (with 10-mA current sink). Pins P8 to P8 , PA to PA , and
2 0 7 0
PB to PB have Schmitt-trigger input circuits.
3 0
For block diagrams of the ports see appendix C, I/O Port Block Diagrams.
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