Description Of Pin Functions - NEC PD703114 User Manual

2.3 Description of Pin Functions

(1) P00 to P05 (Port 0) ... Input
P00 to P05 function as a 6-bit input-only port in which all pins are fixed to input.
Besides functioning as an input port, in control mode, P00 to P05 operate as NMI input, timer/counter output
stop signal input, external interrupt request input, A/D converter (ADC) external trigger input, and timer 3
output stop signal input. Normally, if port pins also have alternate functions, the mode is selected using a port
mode control register. However, there is no such register for P00 to P05. Therefore, the input port cannot be
switched with the NMI input pin, timer/counter output stop signal input pin, external interrupt request input pin,
A/D converter (ADC) external trigger input pin, and timer 3 output stop signal input pin. Read the status of
each pin by reading the port.
(a) Port mode
P00 to P05 are input-only.
(b) Control mode
P00 to P05 also serve as the NMI, ESO0, ESO1, ADTRG0, ADTRG1, INTP0 to INTP4, and TO3OFF
pins, but they cannot be switched.
(i) NMI (Non-maskable interrupt request) ... Input
This is non-maskable interrupt request input.
(ii) ESO0, ESO1 (Emergency shut off) ... Input
These pins input timer 00 and timer 01 output stop signals.
(iii) INTP0 to INTP4 (External interrupt input) ... Input
These are external interrupt request input pins.
(iv) ADTRG0, ADTRG1 (A/D trigger input) ... Input
These are A/D converter external trigger input pins.
(v) TO3OFF (Timer output 3 off) ... Input
This is a timer output stop signal input pin.
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CHAPTER 2 PIN FUNCTIONS
User's Manual U15195EJ5V0UD