timer_example2.c

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#include "timer.h"
/*

Description
*******************

This example will start a timer, and generate a pwm on the output

To get this example running on your STK1000, connect a 10 pin cable from J1 to J15 (LED) and from J2 to J25 (SWITCH). We will use the LEDs as output and the switches as input. When pressing the switch labelled SW1 (connected to Timer/Counter instance 2, channel 0), the RC value for the  corresponding timer will be loaded into the RA register of a Timer/Counter instance 1, channel 1. The SWITCH is connected to a Timer/Counter input, while the LED is connected to a output. When the dip-switch is pressed, it will read a new value for the timer/counter from the RA for the input channel and load this into RA for the output channel.

The pulse width(while the LED is shining) reflects the RA value captured from the input.

*/



/*      Useful pin behaviour definitions
        Used for compare trigger actions */
#define NOOP                    0
#define SET                             1
#define CLEAR                   2
#define TOGGLE                  3

#define NONE                    0
#define RISING_EDGE             1
#define FALLING_EDGE    2
#define EACH_EDGE               3


/*      Generic definitions */
#define TRUE                    1
#define FALSE                   0

/* Prototypes for initialization for Timer/Counter channels */
/* Added to keep main smaller and more readable */
void init_timer_input( unsigned int instance, unsigned int channel);
void init_timer_output( unsigned int instance, unsigned int channel);

int main( int argc, char * argv[] )
{

        avr32_pio_t *piob = (void *) AVR32_PIOB_ADDRESS;


        /* The channel number and instance is used in several functions */
        /* It's defined as local variable for ease-of-use and readability */
        int output_instance = 1;
        int output_channel = 1;

        int input_instance = 2;
        int input_channel = 0;

        /* Used for reading the RA value for the input Timer/Counter instance */
        int ra=0;

        /* Enable Timer module on PIOB */
        piob->pdr = 0x0000ffff;
        piob->asr = 0x0000ffff;

        /* Init the Timer */
        init_timer_input(input_instance, input_channel);
        init_timer_output(output_instance, output_channel);

        /* Set the compare triggers*/
        timer_write_ra(output_instance, output_channel, 0x2000 );

        /* Start the timers */
        timer_start(output_instance, output_channel);
        timer_start(input_instance, input_channel);

        while(1){
                ra = timer_read_ra(input_instance, input_channel);
                if(ra>0){
                        timer_write_ra(output_instance, output_channel, ra);
                        ra=0;
                }
        }
        return 0;
}


void init_timer_input( unsigned int instance, unsigned int channel)
{
        struct timer_capture_opt_t capture_opt;

        /* Options for Capture mode */
        capture_opt.channel = channel;
        capture_opt.tcclks = TIMER_CLOCK_SOURCE_TC5;
        capture_opt.clki = FALSE;
        capture_opt.burst = FALSE;
        capture_opt.ldbstop = FALSE;
        capture_opt.ldbdis = FALSE;
        capture_opt.etrgedg = FALLING_EDGE;
        capture_opt.abetrg = FALSE; /* Select TIOB */
        capture_opt.cpctrg = TRUE;
        capture_opt.ldra = FALLING_EDGE;
        capture_opt.ldrb = NONE;

        /*Initialize the timer*/
        timer_init_capture(instance, &capture_opt);
}


void init_timer_output( unsigned int instance, unsigned int channel)
{
        struct timer_waveform_opt_t waveform_opt;

        /* Options for Waveform genration */
        waveform_opt.channel = channel;
        waveform_opt.tcclks = TIMER_CLOCK_SOURCE_TC4;
        waveform_opt.clki = FALSE;
        waveform_opt.burst = FALSE;
        waveform_opt.cpcstop = FALSE;
        waveform_opt.cpcdis = FALSE;
        waveform_opt.eevtedg = FALSE;
        waveform_opt.eevt = 0;
        waveform_opt.enetrg = FALSE;
        waveform_opt.wavsel = TIMER_WAVEFORM_SEL_UP_MODE;

        waveform_opt.acpa = CLEAR;
        waveform_opt.acpc = SET;
        waveform_opt.aeevt = NOOP;
        waveform_opt.aswtrg = NOOP;

        waveform_opt.bcpb = NOOP;
        waveform_opt.bcpc = NOOP;
        waveform_opt.beevt = NOOP;
        waveform_opt.bswtrg = NOOP;

        /* Initialize the timer */
        timer_init_waveform(instance, &waveform_opt);
}

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