Renesas F-ZTAT H8 Series, Hardware Manual

Page: 221 / 562

8. I/O Ports
Rev.3.00 Jul. 19, 2007 page 195 of 532
REJ09B0397-0300
Port Data Register 4 (PDR4)
Bit 7 6 5 4 3 2 1 0
⎯ ⎯ ⎯ ⎯
P4
3
P4
2
P4
1
P4
0
Initial value 1 1 1 1
Undefined
0 0 0
Read/Write
⎯ ⎯ ⎯ ⎯
R R/W R/W R/W
PDR4 is an 8-bit register that stores data for port 4 pins P4
2
to P4
0
. If port 4 is read while PCR4
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.
The pin state is always read from bit 3 (P4
3
).
Upon reset, PDR4 is initialized to H'F8.
Port Control Register 4 (PCR4)
Bit 7 6 5 4 3 2 1 0
⎯ ⎯ ⎯ ⎯ ⎯
PCR4
2
PCR4
1
PCR4
0
Initial value 1 1 1 1 1 0 0 0
Read/Write
⎯ ⎯ ⎯ ⎯ ⎯
W W W
PCR4 controls whether each of the port 4 pins P4
2
to P4
0
functions as an 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. The settings in PCR4 and in PDR4 are valid only when the
corresponding pin is designated in SCR3 as a general I/O pin.
Upon reset, PCR4 is initialized to H'F8.
PCR4 is a write-only register. All bits are read as 1.