Operations Of Port C - Fujitsu F2MC-8FX Hardware Manual

CHAPTER 9 I/O PORT
9.10.2

Operations of Port C

This section describes the operations of port C.
Operations of Port C
Operation as an output port
• Setting the corresponding DDR bit to "1" sets a pin as an output port.
• For a peripheral function sharing pins, disable its output.
• When a pin is set as an output port, it outputs the value of the PDR to pins.
• If data is written to the PDR, the value is stored in the output latch and output to the pin as it is.
• Reading the PDR returns the PDR value.
Operation as an input port
• Setting the corresponding DDR bit to "0" sets a pin as an input port.
• For a peripheral function sharing pins, disable its output.
• When using the LCD shared pin as an input port, set the port input control bits (PICTL) in the LCDC
enable register (LCDCE1) to "1".
• If data is written to the PDR, the value is stored in the output latch but not output to the pin.
• Reading the PDR returns the pin value. However, the read-modify-write command returns the PDR
value.
Operation at reset
• Resetting the CPU initializes PICTL bits in the DDR and LCDE1 to "0", and sets the port input
disabled.
Operation in stop mode and watch mode
• After moving to stop mode or watch mode, setting the standby control register pin state specification bit
(STBC:SPL) to "1" forces the pin into high impedance, regardless of the value of the DDR register.Note
that input is locked to "L" and blocked, in order to prevent leaks from freed input. If, however,peripheral
function input is enabled for the interrupt pin selection circuit (TRG0~7), input is enabled and not
blocked.
• If the pin state specification bit is "0", the state remains in port I/O or peripheral function I/O, and the
output level is maintained.
Behavior during peripheral function output
• When the output enable bit of a peripheral function is set to enabled, the corresponding pin goes
toperipheral function output.
• When the output of the peripheral function is enabled, the pin value is read by reading the PDR
register.Consequently, it is possible to read the output value of a peripheral function by reading the PDR
register. Note, however, that for read-modify-write commands, the value of the PDR register is read.
Behavior during peripheral function input
• Sets the DDR register bit corresponding to the peripheral function input pin to "0" to change to an input
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