HD6433935 Hitachi, HD6433935 Datasheet - Page 167

• Manufacturer Part Number: HD6433935
• Description: 8-Bit MICROCONTROLLER
• Manufacturer: Hitachi

1. Port data register 4 (PDR4)
PDR4 is an 8-bit register that stores data for port 4 pins P4
bits are set to 1, the values stored in PDR4 are read, regardless of the actual pin states. If port 4 is
read while PCR4 bits are cleared to 0, the pin states are read.
Upon reset, PDR4 is initialized to H'F8.
2. Port control register 4 (PCR4)
PCR4 is an 8-bit register for controlling whether each of port 4 pins P4
input pin or output pin. Setting a PCR4 bit to 1 makes the corresponding pin an output pin, while
clearing the bit to 0 makes the pin an input pin. PCR4 and PDR4 settings are valid when the
corresponding pins are designated for general-purpose input/output by SCR3-2.
Upon reset, PCR4 is initialized to H'F8.
PCR4 is a write-only register, which always reads all 1s.
Bit
Initial value
Read/Write
Bit
Initial value
Read/Write
—
—
—
—
7
1
7
1
—
—
—
—
6
1
6
1
—
—
—
—
5
1
5
1
—
—
—
—
4
1
4
1
2
P4
to P4
—
—
R
3
1
3
1
3
0
. If port 4 is read while PCR4
PCR4
R/W
P4
W
2
2
0
2
0
to P4
2
2
0
PCR4
functions as an
R/W
P4
W
1
0
1
0
1
1
PCR4
R/W
P4
W
0
0
0
0
0
0
155