Table of Contents
Advertisement
Section 7 I/O Ports
7.1 Overview
The H8/3039 Series has nine input/output ports (ports 1, 2, 3, 5, 6, 8, 9, A, and B) and one input
port (port 7). Table 7-1 summarizes the port functions. The pins in each port are multiplexed as
shown in table 7-1.
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, and 5 have an input pull-up
control register (PCR) for switching input pull-up transistors on and off.
Ports 1 to 3 and ports 5, 6, and 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 3 and ports 5, 6, 8, 9, A, and
B can drive a Darlington pair. Ports 1, 2, 5, and B can drive LEDs (with 10-mA current sink). Pins
P8
, P8
, PA
to PA
, and PB
to PB
have Schmitt-trigger input circuits.
1
0
7
0
3
0
For block diagrams of the ports see appendix C, I/O Port Block Diagrams.
131
Advertisement
Table of Contents
