hd66100 Renesas Electronics Corporation., hd66100 Datasheet - Page 164

• Manufacturer Part Number: hd66100
• Description: H8/3867 Series
• Manufacturer: Renesas Electronics Corporation.

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.
8.4.3
Table 8.9 shows the port 4 pin functions.
Table 8.9
Pin
P4
P4
P4
Bit
Initial value
Read/Write
3
2
1
/IRQ
/TXD
/RXD
0
32
32
Pin Functions
Port 4 Pin Functions
Pin Functions and Selection Method
The pin function depends on bit IRQ0 in PMR3.
The pin function depends on bit TE in SCR3-2, bit SPC32 in SPCR, and bit
PCR4
The pin function depends on bit RE in SCR3-2 and bit PCR4
—
—
7
1
Pin function
Pin function
Pin function
2
SPC32
PCR4
PCR4
IRQ0
RE
in PCR4.
TE
32
2
1
—
—
6
1
—
—
5
1
P4
P4
2
1
input pin
input pin
P4
0
0
3
—
—
4
1
input pin
0
0
0
0
—
—
3
1
P4
P4
2
1
output pin
output pin
PCR4
1
1
W
2
0
2
to P4
2
IRQ
0
PCR4
1
functions as an
in PCR4.
W
TXD
0
1
0
RXD
input pin
1
1
32
32
*: Don’t care
output pin
PCR4
1
1
*
1
*
input pin
W
0
0
0
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