Moved arduino specific C files and started working on PWM.

ard/pins.c

@@ -0,0 +1,151 @@
+#include "pins.h"
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+const unsigned char LOW = 0x00;
+const unsigned char HIGH = 0x01;
+const unsigned char INPUT = 0x00;
+const unsigned char OUTPUT = 0x01;
+
+// analog pins (digital range from 0 to 13)
+const unsigned char A0 = 0x0e;
+const unsigned char A1 = 0x0f;
+const unsigned char A2 = 0x10;
+const unsigned char A3 = 0x11;
+const unsigned char A4 = 0x12;
+const unsigned char A5 = 0x13;
+const unsigned char A6 = 0x14;
+const unsigned char A7 = 0x15;
+
+void analog_read_duty_cycle();
+unsigned char map_analog_pin(unsigned char);
+
+void pin_mode(unsigned char pin, unsigned char mode){
+	if(pin > A7){
+		return;
+	}
+
+	if(pin < 8){
+		// digital pin 0-7
+		if(mode == INPUT){
+			DDRD &= ~_BV(pin);
+		}
+		else{
+			DDRD |= _BV(pin);
+		}
+	}
+	else if(pin < 14){
+		// digital pin 8-13
+		pin -= 8;
+
+		if(mode == INPUT){
+			DDRB &= ~_BV(pin);
+		}
+		else{
+			DDRB |= _BV(pin);
+		}
+	}
+	else{
+		// analog pin 0-7
+		pin -= 14;
+
+		if(mode == INPUT){
+			DDRC &= ~_BV(pin);
+		}
+		else{
+			DDRC |= _BV(pin);
+		}
+	}
+}
+
+int digital_read(unsigned char pin){
+	if(pin > 13){
+		return 0;
+	}
+
+	if(pin < 8){
+		// pin 0-7
+		return PIND&_BV(pin) ? 1 : 0;
+	}
+
+	// pin 8-13
+	pin -= 8;
+	return PINB&_BV(pin) ? 1 : 0;
+}
+
+void digital_write(unsigned char pin, unsigned char value){
+	if(pin > 13){
+		return;
+	}
+
+	if(pin < 8){
+		// pin 0-7
+		if(value == HIGH){
+			PORTD |= _BV(pin);
+		}
+		else{
+			PORTD &= ~_BV(pin);
+		}
+	}
+	else{
+		// pin 8-13
+		pin -= 8;
+
+		if(value == HIGH){
+			PORTB |= _BV(pin);
+		}
+		else{
+			PORTB &= ~_BV(pin);
+		}
+	}
+}
+
+unsigned int analog_read(unsigned char pin){
+	pin = map_analog_pin(pin);
+
+	if(pin > 7){
+		return 0;
+	}
+
+	// enable ADC (128 bit ADPS scaling factor 0x07),
+	// disable digital input buffer (DIDR0)
+	ADCSRA = _BV(ADEN)|_BV(ADIE)|0x07;
+	ADMUX = _BV(REFS0)|pin;
+	DIDR0 |= _BV(pin);
+	ADCSRA |= _BV(ADSC); // start
+
+	// wait for it to finish
+	while(ADCSRA&_BV(ADSC));
+
+	// return 10 bit value
+	return ADC;
+}
+
+void analog_write(unsigned char pin, unsigned int value){
+	pin = map_analog_pin(pin);
+
+	if(pin > 7){
+		return;
+	}
+
+	if(value == HIGH){
+		PORTC |= _BV(pin);
+	}
+	else{
+		PORTC &= ~_BV(pin);
+	}
+}
+
+// maps A0-A7 to 0-7
+unsigned char map_analog_pin(unsigned char pin){
+	if(pin > 7){
+		return pin-A0;
+	}
+
+	return pin;
+}
+
+// analog to digital converter interrupt handler
+ISR(ADC_vect){
+	// required but not used...
+}