NEC PD75402A, PD75P402 user manual Digital Input/Output Port Types and Characteristics

CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS

5.1.1Digital Input/Output Port Types, Characteristics and Configuration

The different types of digital input/output ports are shown in Table 5-1, and the configuration of each port is shown

in Figs. 5-2, 5-3, 5-4 and 5-5.

Table 5-1 Digital Input/Output Port Types and Characteristics

Port	Function	Operation/Characteristics		Remarks
(Symbol)
PORT0	4-bit input	Can always be read or tested	Pins also function as SO/SB0, SI,
PORT1		regardless of dual-function pin	SCK,	INT0, INT2. (See chapter 1.)
		operating mode.
PORT3*	4-bit input/output	Can be set to input or output
		mode bit by bit.
PORT2		Can be set to input or output	Port 2 pins also function as PCL.
PORT6*		mode as a 4-bit unit.
PORT5*	4-bit input/ output	Can be set to input or output	Internal pull-up resistor can be
	(N-ch open-drain,	mode as a 4-bit unit.	specified bit by bit by mask
	up to 10 V)		option. (μPD75402A only.)

*LED direct drive capability

On the μPD75402A, a pull-up resistor can be incorporated on chip for all port pins except pins P00, P10. On the μPD75P402, a pull-up resistor can be incorporated on chip for all port pins except pins P00, P10, and P50 through P53 (see section 5.5).

P10 has a dual function as the external vectored interrupt input pin, and has an on-chip circuit for noise elimination by the sampling clock (see section 6.2 for details).

Upon RESET input the output latches of ports 2, 3, 5 and 6 are cleared, the output buffer is turned off, and input mode is set.

42