6 Appendix

TCD Two Ramp Mode with PLL Code Example

#include <avr/io.h>

#define ON_TIME_START_WOA   0x3FF
#define ON_TIME_CYCLES_WOA  0x199
#define ON_TIME_START_WOB   0x3FF
#define ON_TIME_CYCLES_WOB  0x333

void CLK_Init(void);
void PORT_Init(void);
void TCD_Init(void);

void CLK_Init(void)
{
    /* Set OSCHF as main clock source */
    _PROTECTED_WRITE(CLKCTRL.MCLKCTRLA, CLKCTRL_CLKSEL_OSCHF_gc);
    
    /* Wait for main clock oscillator changing to finish */
    while (CLKCTRL.MCLKSTATUS & CLKCTRL_SOSC_bm)
    {
        ;
    }
    
    /* Change OSCHF frequency to 24 MHz */
    _PROTECTED_WRITE(CLKCTRL.OSCHFCTRLA, CLKCTRL_FREQSEL_24M_gc);
    
    /* Set the multiplication factor for PLL to 2x */
    _PROTECTED_WRITE(CLKCTRL.PLLCTRLA, CLKCTRL_MULFAC_2x_gc);
}

void PORT_Init(void)
{
    /* Configure PORT A PIN4 and PIN5 as output low */
    PORTA.DIRSET |= PIN4_bm | PIN5_bm;
    PORTA.OUTSET |= PIN4_bm | PIN5_bm;
}

void TCD_Init(void)
{
    /* Select the Two Ramp mode */
    TCD0.CTRLB |= TCD_WGMODE_TWORAMP_gc;
    
    /* Load the compare and clear registers */
    TCD0.CMPASET = ON_TIME_START_WOA;
    TCD0.CMPACLR = ON_TIME_START_WOA + ON_TIME_CYCLES_WOA;
    TCD0.CMPBSET = ON_TIME_START_WOB;
    TCD0.CMPBCLR = ON_TIME_START_WOB + ON_TIME_CYCLES_WOB;
    
    /* Enable the PWM channels */
    _PROTECTED_WRITE(TCD0.FAULTCTRL, TCD_CMPAEN_bm | TCD_CMPA_bm);
    _PROTECTED_WRITE(TCD0.FAULTCTRL, TCD_CMPBEN_bm | TCD_CMPB_bm);
    
    /* Wait for TCD to be ready for enabling */
    while (!(TCD0.STATUS & TCD_ENRDY_bm))
    {
        ;
    }
    
    /* Select PLL as input clock and enable TCD */
    TCD0.CTRLA |= TCD_CLKSEL_PLL_gc | TCD_ENABLE_bm;
}

int main(void)
{
    CLK_Init();
    PORT_Init();
    TCD_Init();
    
    while (1) 
    {
        ;
    }
}