HD6433308 Datasheet, PDF (119/349 Pages) Hitachi Semiconductor – Hitachi Single-Chip MicroComputer

5.9 Port 8
Port 8 is a 7-bit input/output port that also provides pins for E clock output, dual-port RAM register
select input, interrupt input, and clock-synchronized serial communication. Table 5-16 lists the pin
functions.
Table 5-16. Port 8 Pin Functions
I/O port
P80 input/output
P81 input/output
P82 input/output
P83 input/output
P84 input/output
P85 input/output
P86 input/output
Auxiliary functions
Expanded modes
Single-chip mode
E clock output
RS0 input
IOS output
RS1 input
—
RS2 input
—
RS3 input
CTxD output /IRQ3 input
CRxD input /IRQ4 input
CSCK input/output /IRQ5 input
Pins of port 8 can drive a single TTL load and a 30pF capacitive load when they are used as output
pins. They can also drive a Darlington pair. When used as input pins, they have programmable
MOS pull-ups.
Table 5-17 details the port 8 registers.
Table 5-17. Port 8 Registers
Name
Abbreviation
Port 8 data direction register P8DDR
Port 8 data register
P8DR
Read/Write
W
R/W
Initial value
H’81 (modes 1 and 2)
H’80 (mode 3)
H'80
Address
H’FFBD
H’FFBF
104