HD6433308 Datasheet, PDF (103/349 Pages) Hitachi Semiconductor – Hitachi Single-Chip MicroComputer

5.5 Port 4
Port 4 is an 8-bit input/output port that also provides the input and output pins for the 8-bit timers
and the output pins for the PWM timers. The pin functions depend on control bits in the control
registers of the timers. Pins not used by the timers are available for general-purpose input/output.
Table 5-8 lists the pin functions, which are the same in both the expanded and single-chip modes.
Table 5-8. Port 4 Pin Functions (Modes 1 to 3)
Usage Pin functions
I/O port P40
P41
P42
P43
P44 P45 P46
P47
Timer TMCI0 TMO0 TMRI0 TMCI1 TMO1 TMRI1 PW0 PW1
See section 7, “8-Bit Timer Module” and section 8, “PWM Timer Module” for details of the timer
control bits.
Pins of port 4 can drive a single TTL load and a 90pF 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 5-9 details the port 4 registers.
Table 5-9. Port 4 Registers
Name
Port 4 data direction register
Port 4 data register
Abbreviation
P4DDR
P4DR
Read/Write
W
R/W
Initial value
H’00
H’00
Address
H’FFB5
H’FFB7
Port 4 Data Direction Register (P4DDR)—H’FFB5
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P47DDR P46DDR P45DDR P44DDR P43DDR P42DDR P41DDR P40DDR
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
P4DDR is an 8-bit register that selects the direction of each pin in port 4. A pin functions as an
output pin if the corresponding bit in P4DDR is set to “1,” and as an input pin if the bit is cleared to
“0.”
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