Description Of Pin Functions - NEC UPD703116 User Manual

2.3 Description of Pin Functions

(1) P00 to P07 (Port 0) ... Input
Port 0 is an 8-bit input-only port in which all pins are fixed for input.
Besides functioning as an input port, in control mode, P00 to P07 operate as NMI input, timer/counter output
stop signal input, external interrupt request input, and A/D converter (ADC) external trigger input. Normally, if
function pins also serve as ports, one mode or the other is selected using a port mode control register.
However, there is no such register for P00 to P07. Therefore, the input port cannot be switched with the NMI
input pin, timer/counter output stop signal input pin, external interrupt request input pin, and A/D converter
(ADC) external trigger input pin. Read the status of each pin by reading the port.
(a) Port mode
P00 to P07 are input-only.
(b) Control mode
P00 to P07 also serve as NMI, ESO0, ESO1, ADTRG0, ADTRG1, and INTP0 to INTP6 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 INTP6 (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.
(2) P10 to P15 (Port 1) ... I/O
Port 1 is a 6-bit I/O port in which input or output can be set in 1-bit units.
Besides functioning as an I/O port, in control mode, P10 to P15 operate as timer/counter I/O and external
interrupt request input.
An operation mode of port or control mode can be selected for each bit and specified by the port 1 mode
control register (PMC1).
(a) Port mode
P10 to P15 can be set to input or output in 1-bit units using the port 1 mode register (PM1).
(b) Control mode
P10 to P15 can be set to port or control mode in 1-bit units using PMC1.
(i) TO10, TO11 (Timer output) ... Output
These pins output timer 10 and timer 11 pulse signals.
(ii) TIUD10, TIUD11 (Timer count pulse input) ... Input
These are external count clock input pins to the up/down counter (timer 10, timer 11).
CHAPTER 2 PIN FUNCTIONS
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