3069RF-ZTAT Datasheet, PDF (289/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

ABWCR and P4DDR are not initialized in software standby mode. Therefore, if a transition is
made to software standby mode while port 4 is functioning as an input/output port and a P4DDR
bit is set to 1, the corresponding pin maintains its output state.
Port 4 Data Register (P4DR): P4DR is an 8-bit readable/writable register that stores output data
for port 4. When port 4 functions as an output port, the value of this register is output. When a bit
in P4DDR is set to 1, if port 4 is read the value of the corresponding P4DR bit is returned. When a
bit in P4DDR is cleared to 0, if port 4 is read the corresponding pin logic level is read.
Bit
Initial value
Read/Write
7
P4 ₇
0
R/W
6
P4 ₆
0
R/W
5
P4 ₅
0
R/W
4
P4 ₄
0
R/W
3
P4 ₃
0
R/W
2
P4 ₂
0
R/W
1
P4 ₁
0
R/W
Port 4 data 7 to 0
These bits store data for port 4 pins
0
P4 ₀
0
R/W
P4DR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode it
retains its previous setting.
Port 4 Input Pull-Up MOS Control Register (P4PCR): P4PCR is an 8-bit readable/writable
register that controls the MOS input pull-up transistors in port 4.
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
P4₇PCR P4₆PCR P4₅PCR P4₄PCR P4₃PCR P4₂PCR P4₁PCR P4₀PCR
0
0
0
0
0
0
0
0
R/W
R/W R/W
R/W
R/W R/W
R/W R/W
Port 4 input pull-up control 7 to 0
These bits control input pull-up transistors built into port 4
In mode 7 (single-chip mode), and in 8-bit bus mode in modes 1 to 5 (expanded modes), when a
P4DDR bit is cleared to 0 (selecting generic input), if the corresponding P4PCR bit is set to 1, the
input pull-up transistor is turned on.
P4PCR is initialized to H'00 by a reset and in hardware standby mode. In software standby mode
it retains its previous setting.
Rev. 5.0, 09/04, page 267 of 978