cmu.c

#include "cmu.h"

/******************************************************************************
 * @brief initialize clock trees for each peripheral in use
          (I2C, LDMA, LEUART, and LETIMER)
 * @param none
 * @return none
 *****************************************************************************/
void cmu_init(void){
// High freq clock tree:
    CMU_ClockSelectSet(cmuClock_HF, cmuSelect_HFRCO);    // route HFRCO to HFCLK branch                     (I2C and LDMA clock tree 1)
    CMU_OscillatorEnable(cmuOsc_HFXO, false, false);     // disable HFXO
    CMU_OscillatorEnable(cmuOsc_HFRCO, true, true);      // enable HFRCO                                    (I2C and LDMA clock tree 2)
    CMU_ClockSelectSet(cmuClock_HFPER, cmuSelect_HFCLK); // route HFCLK to HFPERCLK(high freq periph clk)   (I2C clock tree 3)
    CMU_ClockSelectSet(cmuClock_BUS, cmuSelect_HFCLK);   // route HFCLK to HFBUSCLK                         (LDMA clock tree 3)
    CMU_ClockEnable(cmuClock_HF, true);                  // enable HFCLK                                    (I2C and LDMA clock tree 4)
    CMU_ClockEnable(cmuClock_HFPER, true);               // enable HFPERCLK                                 (I2C clock tree 5)
    CMU_ClockEnable(cmuClock_BUS, true);                 // enable HFBUSCLK                                 (LDMA clock tree 5)
    CMU_HFXOAutostartEnable(true, false, false);

// By default, LFRCO is enabled:
    CMU_OscillatorEnable(cmuOsc_LFRCO, false, false);    // DISABLE LFRCO
    CMU_OscillatorEnable(cmuOsc_ULFRCO, false, false);   // DISABLE ULFRCO

// Low freq clock tree:
    CMU_OscillatorEnable(cmuOsc_LFXO, true, true);       // enable LFXO                                     (LETIMER and LEUART clock tree 1)
    CMU_OscillatorEnable(cmuOsc_ULFRCO, true, true);     // enable ULFRCO                                   (CRYOTIMER clock tree 1)
    CMU_ClockSelectSet(cmuClock_LFA, cmuSelect_LFXO);    // route LFXO to LFACLK                            (LETIMER clock tree 2)
    CMU_ClockEnable(cmuClock_LFA, true);                 // enable LFACLK                                   (LETIMER clock tree 3)
    CMU_ClockSelectSet(cmuClock_LFB, cmuSelect_LFXO);    // route LFXO to LFBCLK                            (LEUART clock tree 2)
    CMU_ClockEnable(cmuClock_LFB, true);                 // enable LFBCLK                                   (LEUART clock tree 3)
    CMU_ClockSelectSet(cmuClock_CRYOTIMER, cmuSelect_ULFRCO);// route ULFRCO to CRYOCLK                     (CRYOTIMER clock tree 2)
    CMU_ClockEnable(cmuClock_CRYOTIMER, true);           // enable CRYOCLK                                  (CRYOTIMER clock tree 3)
    CMU_ClockEnable(cmuClock_CORELE, true);

// Enable peripheral clocks:
    CMU_ClockEnable(cmuClock_GPIO, true);                // connect clock source to GPIO clock
    CMU_ClockEnable(cmuClock_LETIMER0, true);            // connect clock source(LFA) to LETIMER clock tree (LETIMER clock tree 4)
    CMU_ClockEnable(cmuClock_LEUART0, true);             // connect clock source(LFB) to LEUART clock tree  (LEUART clock tree 4)
    CMU_ClockEnable(cmuClock_I2C0, true);                // connect clock source (HFPER) to I2C clock tree  (I2C clock tree 6)
    CMU_ClockEnable(cmuClock_LDMA, true);                // connect clock source (HFBUS) to LDMA clock tree (LDMA clock tree 6)
}