h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 290

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

8.10
Port A is a 4-bit I/O port that also has other functions. The port A has the following registers.
• Port A data direction register (PADDR)
• Port A data register (PADR)
• Port A register (PORTA)
8.10.1
The individual bits of PADDR specify input or output for the pins of port A. PADDR cannot be
read; if it is, an undefined value will be read.
8.10.2
PADR stores output data for the port A pins.
Rev. 2.00, 03/04, page 258 of 534
Bit
7 to 4
3
2
1
0
Bit
7 to 4
3
2
1
0
Bit Name

PA3DDR
PA2DDR
PA1DDR
PA0DDR
Bit Name

PA3DR
PA2DR
PA1DR
PA0DR
Port A
Port A Data Direction Register (PADDR)
Port A Data Register (PADR)
Initial
Value
Undefined 
0
0
0
0
Initial
Value
Undefined 
0
0
0
0
R/W
W
W
W
W
R/W
R/W
R/W
R/W
R/W
Description
Reserved
If these bits are read, an undefined value will be read.
These bits cannot be modified.
When a pin function is specified to a general purpose
I/O, setting this bit to 1 makes the corresponding port A
pin an output pin, while clearing this bit to 0 makes the
pin an input pin.
Description
Reserved
If these bits are read, an undefined value will be read.
These bits cannot be modified.
Output data for a pin is stored when the pin function is
specified to a general purpose output.