Bobcat 225G welder idle controller

main.c

//*****************************************************//
//                      welder.c                       //
//                      2016-4-11                      //
//              Written By David Holdeman              //
//     Miller Bobcat 225G Idle Solenoid Controller     //
//*****************************************************//

//        ATtiny45/85
//        +-------+
// !RESET |*      | VCC
//    PB3 |       | PB2/INT0 - Signal In
//    PB4 |       | PB1      - Signal Out to MOSFET
//    GND |       | PB0
//        +-------+

#include "avr/interrupt.h"
#include "util/delay.h"

volatile int time = 0;

ISR(INT0_vect) {
 time = 0;                  // Reset timer
 PORTB &= ~(1<<PB1);        // Drive pin 1 low (switch solenoid off)
 return;
}

int main(void) {
 DDRB = 0b00000010;         // Set PORTB pin 1 as output, all others as input.

 MCUCR |= (1<<ISC00);       // Set Interrupt on Rising edge of signal
 MCUCR |= (1<<ISC01);

 GIMSK |= (1<<INT0);        // Enable INT0 Interrupt
 sei();                     // Activate interrupts

 PORTB |= (1<<PB1);         // Drive pin 1 high (switch solenoid on)

 while(1) {
  if (PINB2 == 1) {         // Just In Case the input signal is longer than expected,
                            // or we want to run a small/no delay, check whether the input is high
   time = 0;                // And if so, reset the timer
  }
  else if(time >= 200) {    // If we've counted for 2 seconds
   PORTB |= (1<<PB1);       // Drive pin 1 high (switch solenoid on)
  }
  else {
   time++;                  // Count up
  }
  _delay_ms(10);            // Delay 10 milliseconds
 }
}

makefile

DEVICE     = attiny85
CLOCK      = 1000000UL
PROGRAMMER = buspirate
PORT	   = /dev/ttyUSB0
BAUD       = 115200
FILENAME   = main
COMPILE    = avr-gcc -Wall -Os -I /usr/share/arduino/hardware/tools/avr/avr/include/ -DF_CPU=$(CLOCK) -mmcu=$(DEVICE)

all: usb clean build upload

usb:
	ls /dev
	
build:
	$(COMPILE) -c $(FILENAME).c -o $(FILENAME).o
	$(COMPILE) -o $(FILENAME).elf $(FILENAME).o
	avr-objcopy -j .text -j .data -O ihex $(FILENAME).elf $(FILENAME).hex
	avr-size --format=avr --mcu=$(DEVICE) $(FILENAME).elf

upload:
	avrdude -v -p $(DEVICE) -c $(PROGRAMMER) -P $(PORT) -b $(BAUD) -U flash:w:$(FILENAME).hex:i 

clean:
	rm main.o
	rm main.elf
	rm main.hex