EmbeddedSystems/EmbeddedSystemsTHM/Taster.c

#include <avr/io.h>

void 
Taster_init (void){
	DDRD &= ~(0b111<<5);	/* Set bit 5-7 of Data Direction Register D as input */
	DDRC &= ~(1<<2);		/* Set bit 2 of Data Direction Register C as input */
	
	PORTD |= (0b111<<5);	/* Initialize bit 5-7 of PORTD as for pull up resistor */
	PORTC |= (1<<PINC2);	/* Initialize bit 2 of PORTC as for pull up resistor */
	
	/** Disable JTAG so Pin 2 of PORTC can be used as a GPIO
	* Command needs to be run twice - see MCU Control Register Description (23.8.1)
	* Bits 7 – JTD: JTAG Interface Disable
	* [..] The application software must write this bit to the desired value
	* twice within four cycles to change its value. [...]
	*/
	MCUCR |= (1<<JTD);
	MCUCR |= (1<<JTD);
}

uint8_t 
Taster1_get (void){
	/* Check if pin is low 
	-> low active pin 
	-> button is pressed 
	-> return 1 */
	return ((PIND & (1<<PIND7)) == 0);
}

uint8_t 
Taster2_get (void){
	return ((PIND & (1<<PIND6)) == 0);
}

uint8_t 
Taster3_get (void){
	return ((PIND & (1<<PIND5)) == 0);
}

uint8_t 
Taster4_get (void){
	return ((PINC & (1<<PINC2)) == 0);
}