Quadrature Encoder with the Xmega event system

gistfile1.c

#include "usb.h"


// PORT C
#define QDEC1 (1<<2)
#define QDEC2 (1<<3)

int main(void){
	sei();
	
	USB_ConfigureClock();
	USB_Init();
	
	PORTC.DIRSET = PWM1 | PWM2 | (1<<4);
	PORTC.DIRCLR = QDEC1 | QDEC2;
	PORTC.PIN1CTRL = PORT_INVEN_bm;
	
	//Set-up quadrature decoding; see p. 75
	PORTC.PIN2CTRL = PORT_ISC_LEVEL_gc | PORT_OPC_PULLUP_gc;
	PORTC.PIN3CTRL = PORT_ISC_LEVEL_gc | PORT_OPC_PULLUP_gc;
	EVSYS.CH0MUX = EVSYS_CHMUX_PORTC_PIN2_gc;	//P. 77
	EVSYS.CH0CTRL = EVSYS_QDEN_bm | EVSYS_DIGFILT_2SAMPLES_gc;	//p. 78
	TCC1.CTRLD = TC_EVACT_QDEC_gc | TC_EVSEL_CH0_gc;	//pp. 180-1
	TCC1.PER = 4799;	//set period register of the timer/counter to numLines*4 -1 == 4799
	TCC1_CTRLA=TC_CLKSEL_DIV1_gc;
	TCC1.CNT = 0;

	while (1){ 
		USB_Task();
	}
}

/** Event handler for the library USB Control Request reception event. */
bool EVENT_USB_Device_ControlRequest(USB_Request_Header_t* req){
	if ((req->bmRequestType & CONTROL_REQTYPE_TYPE) == REQTYPE_VENDOR){
		if (req->bRequest == 0x10){
			*((uint16_t*) ep0_buf_in) = TCC1.CNT;
			USB_ep0_send(2);
			return true;
		}else if (req->bRequest == 0xBB){
			USB_ep0_send(0);
			USB_ep0_wait_for_complete();
			_delay_us(10000);
			USB_Detach();
			_delay_us(100000);
			void (*enter_bootloader)(void) = (void *) 0x47fc /*0x8ff8/2*/;
			enter_bootloader();
		}
	}
	
	return false;
}