Operations Of Port 0 - Fujitsu F2MC-8FX Hardware Manual

9.2.2

Operations of Port 0

This section describes the operations of port 0.
Operations of Port 0
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 analog input shared pin as an input port, set the corresponding bits in the A/D input
disable register low (AIDRL) to "1".
• When using the LCD shared pin as an input port, select the common/segment pin in LCDC enable
registers (LCDCE1 to 6), and then set the port input control bit (PICTL) in 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 as a peripheral function output
• Setting the output enable bit of a peripheral function sets the corresponding pin as a peripheral function
output.
• The pin value can be read from the PDR register even if the peripheral function output is enabled.
Therefore, the output value of a peripheral function can be read by the read operation on PDR register.
However, the read-modify-write command returns the PDR value.
Operation as a peripheral function input
• Set the DDR register bit, which is corresponding to the peripheral function input pin, to "0" to set a pin
as an input port.
• Reading the PDR register returns the pin value, regardless of whether the peripheral function uses an
input pin. However, the read-modify-write command returns the PDR value.
Operation at reset
• Resetting the CPU initializes the DDR values to "0", and sets the port input enabled.
Operation of the input level selection register
• Writing "1" to the bit0 of ILSR2 register changes the input level for Port0 from hysteresis input level to
automotive input level. When bit0 of ILSR2 register is "0", it becomes hysteresis input level.
CHAPTER 9 I/O PORT
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