Setting The I/O Mode And Control Mode; Block Diagram Of P33 (Port 3) - NEC PD78212 User Manual

8-bit single-chip microcomputer sub-series

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5.4.2 Setting the I/O Mode and Control Mode

The port 3 mode register (PM3) can put each pin of port 3 in either the input or output mode independently of the

other pins, as shown in Fig. 5-14.

The PM3 register is loaded with data using an 8-bit data transfer instruction; it cannot be bit-manipulated or read-

In addition to I/O port functions, each pin of port 3 works as a control signal pin. As shown in Fig. 5-15, the port

3 mode control register (PMC3) can specify the mode of control for each pin.

Fig. 5-13 Block Diagram of P33 (Port 3)

Pull-up resistor option register

Port 3 mode register

Output latch

Output disable

Chapter 5 Port Functions