Datasheet

617
• Bit 2—PA1 Mode (PA1MD): Selects the function of the PA1/TxD0 pin.
Bit 2: PA1MD Description
0 General input/output (PA1) (initial value)
1 Transmit data output (TxD0)
• Bit 1—Reserved: This bit always reads as 0. The write value should always be 0.
• Bit 0—PA0 Mode (PA0MD): Selects the function of the PA0/RxD0 pin.
Bit 0: PA0MD Description
0 General input/output (PA0) (initial value)
1 Receive data input (RxD0)
18.3.5 Port B I/O Register (PBIOR)
The port B I/O register (PBIOR) is a 16-bit read/write register that selects input or output for the
ten port B pins. Bits PB9IOR–PB0IOR correspond to the PB9/IRQ7/A21/ADTRG pin to PB0/A16
pin. PBIOR is enabled when the port B pins function as input/outputs (PB9–PB0). For other
functions, it is disabled.
For port B pin functions PB9–PB0, a given pin in port B is an output pin if its corresponding
PBIOR bit is set to 1, and an input pin if the bit is cleared to 0.
PBIOR is initialized to H'0000 by external power-on reset; however, it is not initialized for manual
resets, reset by WDT, standby mode, or sleep mode, so the previous data is maintained.
Bit: 15 14 13 12 11 10 9 8
——————PB9
IOR
PB8
IOR
Initial value: 0 0 0 0 0 0 0 0
R/W: R R R R R R R/W R/W
Bit: 7 6 5 4 3 2 1 0
PB7
IOR
PB6
IOR
PB5
IOR
PB4
IOR
PB3
IOR
PB2
IOR
PB1
IOR
PB0
IOR
Initial value: 0 0 0 0 0 0 0 0
R/W: R/W R/W R/W R/W R/W R/W R/W R/W