HD6432621 Hitachi, HD6432621 Datasheet - Page 253

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Section 9 I/O Ports
9.1
Overview
The H8S/2626 Series and H8S/2623 Series have seven I/O ports (ports 1 and A to F), and two
input-only ports (ports 4 and 9).
Table 9-1 summarizes the port functions. The pins of each port also have other functions.
Each I/O port includes a data direction register (DDR) that controls input/output, a data register
(DR) that stores output data, and a port register (PORT) used to read the pin states. The input-only
ports do not have a DR or DDR register.
Ports A to E have a built-in pull-up MOS function, and in addition to DR and DDR, have a MOS
input pull-up control register (PCR) to control the on/off state of MOS input pull-up.
Ports A to C include an open-drain control register (ODR) that controls the on/off state of the
output buffer PMOS.
Ports 10 to 13, A0 to A3, and B to E can drive a single TTL load and 50 pF capacitive load when
used as expansion bus control signal output pins. In other cases these ports, together with ports 14
to 17 and 3, can drive a single TTL load and 30 pF capacitive load. All the I/O ports can drive a
Darlington transistor when in output mode. Ports 1, A, B, and C can drive an LED (10 mA sink
current).
See Appendix C, I/O Port Block Diagrams, for a block diagram of each port.
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