NEC PD75402A Manuale Utente

CHAPTER 2. PIN FUNCTIONS

Port 0

Dual-Function

Pin Port 1

Dual-Function Pin

P00

P10

INT0

P01

SCK

P12

INT2

P02

SO/SB0

P03

2.2

NORMAL OPERATING MODE

2.2.1

P00 to P03 (Port 0) ..... SCK, SO/SB0, SI Dual-Function Input

P10, P12 (Port 1) ..... INT0, INT2 Dual-Function Input

P00 to P03 are the 4-bit input port: Port 0’s input pins. P10 and P12 are the 2-bit input port: Port 1’s input pins.

Ports 0 and 1 also have the functions of the various control signal pins shown in Table 2-1 in addition to the

functions as input ports. The status of each of Ports 0 and 1 is always inputtable irrespective of the dual-function

pin operation.

Both Ports 0 and 1 have Schmitt-triggered input to prevent malfunction by noise. P10 is built in with the noise

eliminator by the sampling clock and P12 is built in with the noise eliminator by analog delay.

Ports 0 and 1 allow to designate to build in the pull-up resistor respectively in 3-bit units (P01 to P03) and bit-

wise (P12 only). Such designation is made using the pull-up resistor designation register (POGA). Neither P00 or

P10 can be built in with the pull-up resistor.

Any of these pins assumes the input port mode at RESET input.

Table 2-3 Port 0’s, 1’s Dual-Function Pins