Port Direction Register (Ddr0 To Ddrb) - Fujitsu F2MC-16LX Hardware Manual

16-bit microcontroller mb90330 series

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Port Direction Register (DDR0 to DDRB)

The configuration and functions of the port direction register are described.

Port Direction Register (DDR0 to DDRB)

Figure 8.2-2 shows the list of the port direction register (DDR0 to DDRB).

When each terminal functions as a port

When each terminal functions as a port, controls the corresponding each terminal as follows.

• 0: Input mode.

• 1: Output mode reset sets to "0".

When accessing the DDR0 to DDRB registers by using the instruction of the read modify write

system (instructions such as bit set) is made, the bit targeted by an instruction becomes the defined

value, while the content of the output register set with the other bit changes to the input value to the

pin. Therefore, be sure to write an expected value into PDR firstly, and then set DDR, and finally

change to the output when changing the input pin to the output pin is made.

Figure 8.2-2 List of Port Direction Register (DDR0 to DDRB)

CHAPTER 8 I/O PORT

Initial value