void
SystemInit(void)
{
// Setup flash to work with 48Mhz clock
NVMCTRL->CTRLB.reg = NVMCTRL_CTRLB_RWS_HALF;
// Enable external 32Khz crystal
uint32_t val = (SYSCTRL_XOSC32K_STARTUP(6)
| SYSCTRL_XOSC32K_XTALEN | SYSCTRL_XOSC32K_EN32K);
SYSCTRL->XOSC32K.reg = val;
SYSCTRL->XOSC32K.reg = val | SYSCTRL_XOSC32K_ENABLE;
while (!(SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_XOSC32KRDY))
;
// Reset GCLK
GCLK->CTRL.reg = GCLK_CTRL_SWRST;
while (GCLK->CTRL.reg & GCLK_CTRL_SWRST)
;
// Route 32Khz clock to DFLL48M
GCLK->GENDIV.reg = GCLK_GENDIV_ID(CLK_32K);
GCLK->GENCTRL.reg = (GCLK_GENCTRL_ID(CLK_32K)
| GCLK_GENCTRL_SRC_XOSC32K | GCLK_GENCTRL_GENEN);
GCLK->CLKCTRL.reg = (GCLK_CLKCTRL_ID(MCLK_DFLL48M)
| GCLK_CLKCTRL_GEN(CLK_32K) | GCLK_CLKCTRL_CLKEN);
// Configure DFLL48M clock
SYSCTRL->DFLLCTRL.reg = 0;
uint32_t mul = DIV_ROUND_CLOSEST(CONFIG_CLOCK_FREQ, CLK_32K_FREQ);
SYSCTRL->DFLLMUL.reg = (SYSCTRL_DFLLMUL_CSTEP(31)
| SYSCTRL_DFLLMUL_FSTEP(511)
| SYSCTRL_DFLLMUL_MUL(mul));
SYSCTRL->DFLLCTRL.reg = (SYSCTRL_DFLLCTRL_MODE | SYSCTRL_DFLLCTRL_WAITLOCK
| SYSCTRL_DFLLCTRL_QLDIS
| SYSCTRL_DFLLCTRL_ENABLE);
uint32_t ready = (SYSCTRL_PCLKSR_DFLLRDY | SYSCTRL_PCLKSR_DFLLLCKC
| SYSCTRL_PCLKSR_DFLLLCKF);
while ((SYSCTRL->PCLKSR.reg & ready) != ready)
;
// Switch main clock to DFLL48M clock
GCLK->GENDIV.reg = GCLK_GENDIV_ID(CLK_MAIN);
GCLK->GENCTRL.reg = (GCLK_GENCTRL_ID(CLK_MAIN)
| GCLK_GENCTRL_SRC_DFLL48M
| GCLK_GENCTRL_IDC | GCLK_GENCTRL_GENEN);
}
void main_clock_init (void)
{
/* enable the xosc32k and set the start up time */
SYSCTRL->XOSC32K.reg = SYSCTRL_XOSC32K_STARTUP(6) | SYSCTRL_XOSC32K_EN32K |
SYSCTRL_XOSC32K_XTALEN | SYSCTRL_XOSC32K_ENABLE;
while (!SYSCTRL->PCLKSR.bit.XOSC32KRDY){}
/* enable the generic clock GEN1 and configure the XOSC32K as clock source for it */
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID_GCLK1 | GCLK_GENCTRL_SRC_XOSC32K |
GCLK_GENCTRL_GENEN | GCLK_GENCTRL_IDC;
while (GCLK->STATUS.bit.SYNCBUSY){}
/* Enable the DFLL and set the operation mode as closed loop */
SYSCTRL->DFLLCTRL.reg = SYSCTRL_DFLLCTRL_ENABLE | SYSCTRL_DFLLCTRL_MODE;
while(!SYSCTRL->PCLKSR.bit.DFLLRDY){}
/* Load the Multiply factor, Coarse Step and fine Step for DFLL */
SYSCTRL->DFLLMUL.reg = SYSCTRL_DFLLMUL_CSTEP(0x1F/4) | SYSCTRL_DFLLMUL_FSTEP(0xFF/4) |
SYSCTRL_DFLLMUL_MUL(1465);
/* Enable the Generic Clock GEN 1 as DFLL48 as Reference */
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | GCLK_CLKCTRL_ID(0);
/* wait for fine lock */
while(!SYSCTRL->PCLKSR.bit.DFLLLCKF){}
/* Set the NVM Read Wait States to 1, Since the operating frequency 48 MHz */
NVMCTRL->CTRLB.bit.RWS = 1;
/* Enable the Generic Clock 0 and Configure the DFLL as Clock Source for it*/
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID_GCLK0 | GCLK_GENCTRL_SRC_DFLL48M | GCLK_GENCTRL_GENEN |
GCLK_GENCTRL_IDC;
while(GCLK->STATUS.bit.SYNCBUSY){}
}
void SystemInit( void )
{
/* Set 1 Flash Wait State for 48MHz, cf tables 20.9 and 35.27 in SAMD21 Datasheet */
NVMCTRL->CTRLB.bit.RWS = NVMCTRL_CTRLB_RWS_HALF_Val ;
/* Turn on the digital interface clock */
PM->APBAMASK.reg |= PM_APBAMASK_GCLK ;
/* ----------------------------------------------------------------------------------------------
* 1) Enable XOSC32K clock (External on-board 32.768Hz oscillator)
*/
SYSCTRL->XOSC32K.reg = SYSCTRL_XOSC32K_STARTUP( 0x6u ) | /* cf table 15.10 of product datasheet in chapter 15.8.6 */
SYSCTRL_XOSC32K_XTALEN | SYSCTRL_XOSC32K_EN32K ;
SYSCTRL->XOSC32K.bit.ENABLE = 1 ; /* separate call, as described in chapter 15.6.3 */
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_XOSC32KRDY) == 0 )
{
/* Wait for oscillator stabilization */
}
/* Software reset the module to ensure it is re-initialized correctly */
/* Note: Due to synchronization, there is a delay from writing CTRL.SWRST until the reset is complete.
* CTRL.SWRST and STATUS.SYNCBUSY will both be cleared when the reset is complete, as described in chapter 13.8.1
*/
GCLK->CTRL.reg = GCLK_CTRL_SWRST ;
while ( (GCLK->CTRL.reg & GCLK_CTRL_SWRST) && (GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY) )
{
/* Wait for reset to complete */
}
/* ----------------------------------------------------------------------------------------------
* 2) Put XOSC32K as source of Generic Clock Generator 1
*/
GCLK->GENDIV.reg = GCLK_GENDIV_ID( GENERIC_CLOCK_GENERATOR_XOSC32K ) ; // Generic Clock Generator 1
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* Write Generic Clock Generator 1 configuration */
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID( GENERIC_CLOCK_GENERATOR_XOSC32K ) | // Generic Clock Generator 1
GCLK_GENCTRL_SRC_XOSC32K | // Selected source is External 32KHz Oscillator
// GCLK_GENCTRL_OE | // Output clock to a pin for tests
GCLK_GENCTRL_GENEN ;
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* ----------------------------------------------------------------------------------------------
* 3) Put Generic Clock Generator 1 as source for Generic Clock Multiplexer 0 (DFLL48M reference)
*/
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID( GENERIC_CLOCK_MULTIPLEXER_DFLL48M ) | // Generic Clock Multiplexer 0
GCLK_CLKCTRL_GEN_GCLK1 | // Generic Clock Generator 1 is source
GCLK_CLKCTRL_CLKEN ;
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* ----------------------------------------------------------------------------------------------
* 4) Enable DFLL48M clock
*/
/* DFLL Configuration in Closed Loop mode, cf product datasheet chapter 15.6.7.1 - Closed-Loop Operation */
/* Remove the OnDemand mode, Bug http://avr32.icgroup.norway.atmel.com/bugzilla/show_bug.cgi?id=9905 */
SYSCTRL->DFLLCTRL.bit.ONDEMAND = 0 ;
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLRDY) == 0 )
{
/* Wait for synchronization */
}
SYSCTRL->DFLLMUL.reg = SYSCTRL_DFLLMUL_CSTEP( 31 ) | // Coarse step is 31, half of the max value
SYSCTRL_DFLLMUL_FSTEP( 511 ) | // Fine step is 511, half of the max value
SYSCTRL_DFLLMUL_MUL( (__CLOCK_48MHz/__CLOCK_32KHz) ) ; // External 32KHz is the reference
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLRDY) == 0 )
{
/* Wait for synchronization */
}
/* Write full configuration to DFLL control register */
SYSCTRL->DFLLCTRL.reg |= SYSCTRL_DFLLCTRL_MODE | /* Enable the closed loop mode */
SYSCTRL_DFLLCTRL_WAITLOCK |
SYSCTRL_DFLLCTRL_QLDIS ; /* Disable Quick lock */
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLRDY) == 0 )
{
/* Wait for synchronization */
}
/* Enable the DFLL */
SYSCTRL->DFLLCTRL.reg |= SYSCTRL_DFLLCTRL_ENABLE ;
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLLCKC) == 0 ||
(SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLLCKF) == 0 )
{
/* Wait for locks flags */
}
while ( (SYSCTRL->PCLKSR.reg & SYSCTRL_PCLKSR_DFLLRDY) == 0 )
{
/* Wait for synchronization */
}
/* ----------------------------------------------------------------------------------------------
* 5) Switch Generic Clock Generator 0 to DFLL48M. CPU will run at 48MHz.
*/
GCLK->GENDIV.reg = GCLK_GENDIV_ID( GENERIC_CLOCK_GENERATOR_MAIN ) ; // Generic Clock Generator 0
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* Write Generic Clock Generator 0 configuration */
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID( GENERIC_CLOCK_GENERATOR_MAIN ) | // Generic Clock Generator 0
GCLK_GENCTRL_SRC_DFLL48M | // Selected source is DFLL 48MHz
// GCLK_GENCTRL_OE | // Output clock to a pin for tests
GCLK_GENCTRL_IDC | // Set 50/50 duty cycle
GCLK_GENCTRL_GENEN ;
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* ----------------------------------------------------------------------------------------------
* 6) Modify PRESCaler value of OSC8M to have 8MHz
*/
SYSCTRL->OSC8M.bit.PRESC = SYSCTRL_OSC8M_PRESC_0_Val ;
SYSCTRL->OSC8M.bit.ONDEMAND = 0 ;
/* ----------------------------------------------------------------------------------------------
* 7) Put OSC8M as source for Generic Clock Generator 3
*/
GCLK->GENDIV.reg = GCLK_GENDIV_ID( GENERIC_CLOCK_GENERATOR_OSC8M ) ; // Generic Clock Generator 3
/* Write Generic Clock Generator 3 configuration */
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID( GENERIC_CLOCK_GENERATOR_OSC8M ) | // Generic Clock Generator 3
GCLK_GENCTRL_SRC_OSC8M | // Selected source is RC OSC 8MHz (already enabled at reset)
// GCLK_GENCTRL_OE | // Output clock to a pin for tests
GCLK_GENCTRL_GENEN ;
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/* ----------------------------------------------------------------------------------------------
* 8) Put OSC8M as source for Generic Clock Generator 2, with freq/8
*/
GCLK->GENDIV.reg = GCLK_GENDIV_ID( GENERIC_CLOCK_GENERATOR_OSC1M ) | 8 << 8; // Generic Clock Generator 4
/* Write Generic Clock Generator 3 configuration */
GCLK->GENCTRL.reg = GCLK_GENCTRL_ID( GENERIC_CLOCK_GENERATOR_OSC1M ) | // Generic Clock Generator 4
GCLK_GENCTRL_SRC_OSC8M | // Selected source is RC OSC 8MHz (already enabled at reset)
// GCLK_GENCTRL_OE | // Output clock to a pin for tests
GCLK_GENCTRL_GENEN ;
while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY )
{
/* Wait for synchronization */
}
/*
* Now that all system clocks are configured, we can set CPU and APBx BUS clocks.
* There values are normally the one present after Reset.
*/
PM->CPUSEL.reg = PM_CPUSEL_CPUDIV_DIV1 ;
PM->APBASEL.reg = PM_APBASEL_APBADIV_DIV1_Val ;
PM->APBBSEL.reg = PM_APBBSEL_APBBDIV_DIV1_Val ;
PM->APBCSEL.reg = PM_APBCSEL_APBCDIV_DIV1_Val ;
SystemCoreClock=__CLOCK_48MHz ;
return;
}
void _sysctrl_init_referenced_generators(void)
{
void *hw = (void *)SYSCTRL;
#if CONF_DFLL_CONFIG == 1
# if CONF_DFLL_USBCRM != 1 && CONF_DFLL_MODE != CONF_DFLL_OPEN_LOOP_MODE
hri_gclk_write_CLKCTRL_reg(GCLK, GCLK_CLKCTRL_ID(0) |
GCLK_CLKCTRL_GEN(CONF_DFLL_GCLK) |
( 1 << GCLK_CLKCTRL_CLKEN_Pos ));
# endif
hri_sysctrl_write_DFLLCTRL_reg(hw, SYSCTRL_DFLLCTRL_ENABLE);
while(!hri_sysctrl_get_PCLKSR_DFLLRDY_bit(hw)) {;
}
hri_sysctrl_write_DFLLMUL_reg(hw, SYSCTRL_DFLLMUL_CSTEP(
CONF_DFLL_CSTEP) |
SYSCTRL_DFLLMUL_FSTEP(CONF_DFLL_FSTEP) |
SYSCTRL_DFLLMUL_MUL(CONF_DFLL_MUL));
hri_sysctrl_write_DFLLVAL_reg(hw, CONF_DFLLVAL);
hri_sysctrl_dfllctrl_reg_t tmp =
( CONF_DFLL_WAITLOCK << SYSCTRL_DFLLCTRL_WAITLOCK_Pos ) |
( CONF_DFLL_BPLCKC << SYSCTRL_DFLLCTRL_BPLCKC_Pos ) |
( CONF_DFLL_QLDIS << SYSCTRL_DFLLCTRL_QLDIS_Pos ) |
( CONF_DFLL_CCDIS << SYSCTRL_DFLLCTRL_CCDIS_Pos ) |
( CONF_DFLL_RUNSTDBY << SYSCTRL_DFLLCTRL_RUNSTDBY_Pos ) |
( CONF_DFLL_USBCRM << SYSCTRL_DFLLCTRL_USBCRM_Pos ) |
( CONF_DFLL_LLAW << SYSCTRL_DFLLCTRL_LLAW_Pos ) |
( CONF_DFLL_STABLE << SYSCTRL_DFLLCTRL_STABLE_Pos ) |
( CONF_DFLL_MODE << SYSCTRL_DFLLCTRL_MODE_Pos ) |
( CONF_DFLL_ENABLE << SYSCTRL_DFLLCTRL_ENABLE_Pos );
hri_sysctrl_write_DFLLCTRL_reg(hw, tmp);
#endif
#if CONF_DPLL_CONFIG == 1
# if CONF_DPLL_REFCLK == SYSCTRL_DPLLCTRLB_REFCLK_GCLK_Val
hri_gclk_write_CLKCTRL_reg(GCLK, GCLK_CLKCTRL_ID(1) |
GCLK_CLKCTRL_GEN(CONF_DPLL_GCLK) | ( 1 << GCLK_CLKCTRL_CLKEN_Pos ));
# endif
hri_sysctrl_write_DPLLCTRLA_reg(hw,
( CONF_DPLL_RUNSTDBY << SYSCTRL_DPLLCTRLA_RUNSTDBY_Pos ) |
( CONF_DPLL_ENABLE << SYSCTRL_DPLLCTRLA_ENABLE_Pos ));
hri_sysctrl_write_DPLLRATIO_reg(hw,
SYSCTRL_DPLLRATIO_LDRFRAC(CONF_DPLL_LDRFRAC) |
SYSCTRL_DPLLRATIO_LDR(CONF_DPLL_LDR));
hri_sysctrl_write_DPLLCTRLB_reg(hw, SYSCTRL_DPLLCTRLB_DIV(
CONF_DPLL_DIV) |
( CONF_DPLL_LBYPASS << SYSCTRL_DPLLCTRLB_LBYPASS_Pos ) |
SYSCTRL_DPLLCTRLB_LTIME(CONF_DPLL_LTIME) |
SYSCTRL_DPLLCTRLB_REFCLK(CONF_DPLL_REFCLK) |
( CONF_DPLL_WUF << SYSCTRL_DPLLCTRLB_WUF_Pos ) |
( CONF_DPLL_LPEN << SYSCTRL_DPLLCTRLB_LPEN_Pos ) |
SYSCTRL_DPLLCTRLB_FILTER(CONF_DPLL_FILTER));
#endif
#if CONF_DFLL_CONFIG == 1
# if CONF_DFLL_ENABLE == 1
if (hri_sysctrl_get_DFLLCTRL_MODE_bit(hw)) {
# if CONF_DFLL_USBCRM == 0
hri_sysctrl_pclksr_reg_t status_mask =
SYSCTRL_PCLKSR_DFLLRDY |
SYSCTRL_PCLKSR_DFLLLCKF | SYSCTRL_PCLKSR_DFLLLCKC;
# else
hri_sysctrl_pclksr_reg_t status_mask =
SYSCTRL_PCLKSR_DFLLRDY;
# endif
while(hri_sysctrl_get_PCLKSR_reg(hw,
status_mask) != status_mask) {;
}
} else {
while(!hri_sysctrl_get_PCLKSR_DFLLRDY_bit(hw)) {;
}
}
# endif
# if CONF_DFLL_ONDEMAND == 1
hri_sysctrl_set_DFLLCTRL_ONDEMAND_bit(hw);
# endif
#endif
#if CONF_DPLL_CONFIG == 1
# if CONF_DPLL_ENABLE == 1
while (!( hri_sysctrl_get_DPLLSTATUS_ENABLE_bit(hw) ||
hri_sysctrl_get_DPLLSTATUS_LOCK_bit(hw) ||
hri_sysctrl_get_DPLLSTATUS_CLKRDY_bit(hw))) {;
}
# endif
# if CONF_DPLL_ONDEMAND == 1
hri_sysctrl_set_DPLLCTRLA_ONDEMAND_bit(hw);
# endif
#endif
#if CONF_DFLL_CONFIG == 1
while(hri_gclk_get_STATUS_SYNCBUSY_bit(GCLK)) {;
}
#endif
#if CONF_OSC32K_CONFIG == 0 || CONF_OSC32K_ENABLE == 0
/* Disable after all possible configurations needs sync written. */
hri_sysctrl_clear_OSC32K_ENABLE_bit(hw);
#endif
(void)hw;
}
