// CONFIG1
#pragma config FEXTOSC = OFF // FEXTOSC External Oscillator mode Selection bits (Oscillator not enabled)
#pragma config RSTOSC = HFINT1 // Power-up default value for COSC bits (HFINTOSC (1MHz))
#pragma config CLKOUTEN = OFF // Clock Out Enable bit (CLKOUT function is disabled)
#pragma config CSWEN = ON // Clock Switch Enable bit (The NOSC and NDIV bits cannot be changed by user software)
#pragma config FCMEN = ON // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is enabled)
// CONFIG2
#pragma config MCLRE = ON // Master Clear Enable bit (MCLR/VPP pin function is MCLR; Weak pull-up enabled)
#pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config WDTE = SWDTEN // Watchdog Timer Enable bits (WDT controlled by the SWDTEN bit in the WDTCON register)
#pragma config LPBOREN = OFF // Low-power BOR enable bit (ULPBOR disabled)
#pragma config BOREN = ON // Brown-out Reset Enable bits (Brown-out Reset enabled, SBOREN bit ignored)
#pragma config BORV = LOW // Brown-out Reset Voltage selection bit (Brown-out voltage (Vbor) set to 2.45V)
#pragma config PPS1WAY = ON // PPSLOCK bit One-Way Set Enable bit (The PPSLOCK bit can be cleared and set only once; PPS registers remain locked after one clear/set cycle)
#pragma config STVREN = ON // Stack Overflow/Underflow Reset Enable bit (Stack Overflow or Underflow will cause a Reset)
#pragma config DEBUG = OFF // Debugger enable bit (Background debugger disabled)
// CONFIG3
#pragma config WRT = OFF // User NVM self-write protection bits (Write protection off)
#pragma config LVP = ON // Low Voltage Programming Enable bit (Low Voltage programming enabled. MCLR/VPP pin function is MCLR. MCLRE configuration bit is ignored.)
// CONFIG4
#pragma config CP = OFF // User NVM Program Memory Code Protection bit (User NVM code protection disabled)
#pragma config CPD = OFF // Data NVM Memory Code Protection bit (Data NVM code protection disabled)

#include <stdio.h>
#include <stdlib.h>

#include <pic16f18326.h>
#include <xc.h>

#define bOn PORTAbits.RA5 //
unsigned char ucFSMstend=0;

void initSystem(void)
{ OSCCON1 = 0b01100000; OSCFRQ = 0b00000111; // 32 MHz //OSCFRQ = 0b00000110; // 16 MHz //OSCFRQ = 0b00000100; // 8 MHz
TRISAbits.TRISA0 = 0; //out8
TRISAbits.TRISA1 = 0; //out7
TRISAbits.TRISA2 = 0; //out6/ /TRISAbits.TRISA3 = 1; //
TRISAbits.TRISA4 = 1; // RA4 - input OldDischarge(reserv))
TRISAbits.TRISA5 = 1; // RA5 - input OnChargFire
ANSELA = 0b00000000; // all RA - digit pins
TRISCbits.TRISC0 = 0; // out5
TRISCbits.TRISC1 = 0; // out4
TRISCbits.TRISC2 = 0; // out3
TRISCbits.TRISC3 = 0; // out2
TRISCbits.TRISC4 = 0; // out1
TRISCbits.TRISC5 = 0; // out redy
ANSELC = 0x00;
WDTCON = 0b00001110; // Watchdog interval 128 ms, watchdog OFF
WDTCONbits.SWDTEN = 1; // Watchdog ON
}

int main(int argc, char** argv) {
initSystem();

while(1){
if(bOn)
LATC=0xFF;
else
LATC=0x00;
asm("clrwdt");
}// for test

Вероятно уровень "1" входного сигнала низкий и при питании 4 вольта он определяется как 1 а при питании 5 вольт это еще ноль.
Входные уровни PIC
Input High Voltage
I/O ports with TTL buffer
2.0V 4.5V<VDD<5.5V
0.25 VDD +0.8V 1.8V<VDD<4.5V

Большое спасибо, коллега, Вы абсолютно правы.