Fujitsu FR60 Hardware Manual page 279

■ I/O Port Modes
The I/O port has the following three modes:
❍ Port input mode (PFR=0 & DDR=0)
• PDR read: Reads the level of the corresponding external pin.
• PDR write: Writes a setting value to the PDR.
❍ Port output mode (PFR=0 & DDR=1)
• PDR read: Reads the value of the PDR.
• PDR write: Outputs the value of the PDR to the corresponding external pin.
❍ Peripheral output mode (PFR=1 & DDR=x)
• PDR read: Reads the value of the corresponding peripheral output.
• PDR write: Writes a setting value to the PDR.
Notes:
Use byte access to access to the port.
• When a port from port 0 to port A is used as an external bus pin, the external bus function has
priority. Thus, if the DDR register is rewritten while the port is functioning as an external bus pin,
no input/output switching occurs. The DDR register value is enabled when the pin is switched to
a general-purpose pin by changing the PFR register.
• During stop mode (HIZ = 0), the setting of pull-up resistor control register has priority.
• During stop mode (HIZ = 1), the setting of pull-up resistor control register is disable in the
hardware standby state.
• If port pin is used as the external bus terminal, using pull-up resistor is prohibited. Do not write
"1" to the corresponding bit of pull-up resistor control register (PCR).
CHAPTER 5 I/O PORT
259