HD64F3644PV Datasheet, PDF (222/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 8 I/O Ports
PDR9 is an 8-bit register that stores data for port 9 pins P9₄ to P9₀. If port 9 is read while PCR9
bits are set to 1, the values stored in PDR9 are read, regardless of the actual pin states. If port 9 is
read while PCR9 bits are cleared to 0, the pin states are read.
Upon reset, PDR9 is initialized to H'C0.
Port Control Register 9 (PCR9)
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0



PCR94 PCR93 PCR92 PCR91 PCR90
0
0
0
0
0
0
0
0



W
W
W
W
W
PCR9 controls whether each of the port 9 pins P9₄ to P9₀ functions as an input pin or output pin.
Setting a PCR9 bit to 1 makes the corresponding pin an output pin, while clearing the bit to 0
makes the pin an input pin.
Upon reset, PCR9 is initialized to H'C0.
PCR9 is a write-only register, which is always reads as all 1.
8.9.3 Pin Functions
Table 8.24 shows the port 9 pin functions.
Table 8.24 Port 9 Pin Functions
Pin
Pin Functions and Selection Method
P9n
The pin function depends on bit PCR9n in PCR9.
PCR9n
Pin function
0
P9n input pin
(n = 4 to 0)
1
P9n output pin
Rev. 6.00 Sep 12, 2006 page 200 of 526
REJ09B0326-0600