/**
* \brief Enable clock for the USB module
*
* \pre CONFIG_USBCLK_SOURCE must be defined.
*
* \param frequency The required USB clock frequency in MHz:
* \arg \c 6 for 6 MHz
* \arg \c 48 for 48 MHz
*/
void sysclk_enable_usb(uint8_t frequency)
{
uint8_t prescaler;
Assert((frequency == 6) || (frequency == 48));
/*
* Enable or disable prescaler depending on if the USB frequency is 6
* MHz or 48 MHz. Only 6 MHz USB frequency requires prescaling.
*/
if (frequency == 6) {
prescaler = CLK_USBPSDIV_8_gc;
}
else {
prescaler = 0;
}
/*
* Switch to the system clock selected by the user.
*/
switch (CONFIG_USBCLK_SOURCE) {
case USBCLK_SRC_RCOSC:
if (!osc_is_ready(OSC_ID_RC32MHZ)) {
osc_enable(OSC_ID_RC32MHZ);
osc_wait_ready(OSC_ID_RC32MHZ);
#ifdef CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC
if (CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC
!= OSC_ID_USBSOF) {
osc_enable(CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
osc_wait_ready(CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
}
osc_enable_autocalibration(OSC_ID_RC32MHZ,
CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
#endif
}
ccp_write_io((uint8_t *)&CLK.USBCTRL, (prescaler)
| CLK_USBSRC_RC32M_gc
| CLK_USBSEN_bm);
break;
#ifdef CONFIG_PLL0_SOURCE
case USBCLK_SRC_PLL:
pll_enable_config_defaults(0);
ccp_write_io((uint8_t *)&CLK.USBCTRL, (prescaler)
| CLK_USBSRC_PLL_gc
| CLK_USBSEN_bm);
break;
#endif
default:
Assert(false);
break;
}
sysclk_enable_module(SYSCLK_PORT_GEN, SYSCLK_USB);
}
void sysclk_init(void)
{
uint8_t *reg = (uint8_t *)&PR.PRGEN;
uint8_t i;
#ifdef CONFIG_OSC_RC32_CAL
uint16_t cal;
#endif
bool need_rc2mhz = false;
/* Turn off all peripheral clocks that can be turned off. */
for (i = 0; i <= SYSCLK_PORT_F; i++) {
*(reg++) = 0xff;
}
/* Set up system clock prescalers if different from defaults */
if ((CONFIG_SYSCLK_PSADIV != SYSCLK_PSADIV_1)
|| (CONFIG_SYSCLK_PSBCDIV != SYSCLK_PSBCDIV_1_1)) {
sysclk_set_prescalers(CONFIG_SYSCLK_PSADIV,
CONFIG_SYSCLK_PSBCDIV);
}
#if (CONFIG_OSC_RC32_CAL==48000000UL)
MSB(cal) = nvm_read_production_signature_row(
nvm_get_production_signature_row_offset(USBRCOSC));
LSB(cal) = nvm_read_production_signature_row(
nvm_get_production_signature_row_offset(USBRCOSCA));
/*
* If a device has an uncalibrated value in the
* production signature row (early sample part), load a
* sane default calibration value.
*/
if (cal == 0xFFFF) {
cal = 0x2340;
}
osc_user_calibration(OSC_ID_RC32MHZ,cal);
#endif
/*
* Switch to the selected initial system clock source, unless
* the default internal 2 MHz oscillator is selected.
*/
if (CONFIG_SYSCLK_SOURCE == SYSCLK_SRC_RC2MHZ) {
need_rc2mhz = true;
} else {
switch (CONFIG_SYSCLK_SOURCE) {
case SYSCLK_SRC_RC32MHZ:
osc_enable(OSC_ID_RC32MHZ);
osc_wait_ready(OSC_ID_RC32MHZ);
#ifdef CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC
if (CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC
!= OSC_ID_USBSOF) {
osc_enable(CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
osc_wait_ready(CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
}
osc_enable_autocalibration(OSC_ID_RC32MHZ,
CONFIG_OSC_AUTOCAL_RC32MHZ_REF_OSC);
#endif
break;
case SYSCLK_SRC_RC32KHZ:
osc_enable(OSC_ID_RC32KHZ);
osc_wait_ready(OSC_ID_RC32KHZ);
break;
case SYSCLK_SRC_XOSC:
osc_enable(OSC_ID_XOSC);
osc_wait_ready(OSC_ID_XOSC);
break;
#ifdef CONFIG_PLL0_SOURCE
case SYSCLK_SRC_PLL:
if (CONFIG_PLL0_SOURCE == PLL_SRC_RC2MHZ) {
need_rc2mhz = true;
}
pll_enable_config_defaults(0);
break;
#endif
default:
//unhandled_case(CONFIG_SYSCLK_SOURCE);
return;
}
ccp_write_io((uint8_t *)&CLK.CTRL, CONFIG_SYSCLK_SOURCE);
Assert(CLK.CTRL == CONFIG_SYSCLK_SOURCE);
}
if (need_rc2mhz) {
#ifdef CONFIG_OSC_AUTOCAL_RC2MHZ_REF_OSC
osc_enable(CONFIG_OSC_AUTOCAL_RC2MHZ_REF_OSC);
osc_wait_ready(CONFIG_OSC_AUTOCAL_RC2MHZ_REF_OSC);
osc_enable_autocalibration(OSC_ID_RC2MHZ,
CONFIG_OSC_AUTOCAL_RC2MHZ_REF_OSC);
#endif
} else {
osc_disable(OSC_ID_RC2MHZ);
}
#ifdef CONFIG_RTC_SOURCE
sysclk_rtcsrc_enable(CONFIG_RTC_SOURCE);
#endif
}
void sysclk_init(void)
{
uint8_t *reg = (uint8_t *)&PR.PRGEN;
uint8_t i;
#ifdef CONFIG_OSC_RC32_CAL
uint16_t cal;
#endif
/* Turn off all peripheral clocks that can be turned off. */
for (i = 0; i <= SYSCLK_PORT_F; i++) {
*(reg++) = 0xff;
}
/* Set up system clock prescalers if different from defaults */
if ((CONFIG_SYSCLK_PSADIV != SYSCLK_PSADIV_1)
|| (CONFIG_SYSCLK_PSBCDIV != SYSCLK_PSBCDIV_1_1)) {
sysclk_set_prescalers(CONFIG_SYSCLK_PSADIV,
CONFIG_SYSCLK_PSBCDIV);
}
#if (CONFIG_OSC_RC32_CAL==48000000UL)
MSB(cal) = nvm_read_production_signature_row(
nvm_get_production_signature_row_offset(USBRCOSC));
LSB(cal) = nvm_read_production_signature_row(
nvm_get_production_signature_row_offset(USBRCOSCA));
/*
* If a device has an uncalibrated value in the
* production signature row (early sample part), load a
* sane default calibration value.
*
* MODIFIED 16-7-2012 by C.DOGGEN:
* - commented the if statement, otherwise the USART won't work
* - don't know exactly the problem, but this seems to be a workaround.
*/
if (cal == 0xFFFF) {
cal = 0x2340;
}
osc_user_calibration(OSC_ID_RC32MHZ,cal);
#endif
/*
* Switch to the selected initial system clock source, unless
* the default internal 2 MHz oscillator is selected.
*/
if (CONFIG_SYSCLK_SOURCE != SYSCLK_SRC_RC2MHZ) {
bool need_rc2mhz = false;
switch (CONFIG_SYSCLK_SOURCE) {
case SYSCLK_SRC_RC32MHZ:
osc_enable(OSC_ID_RC32MHZ);
osc_wait_ready(OSC_ID_RC32MHZ);
break;
case SYSCLK_SRC_RC32KHZ:
osc_enable(OSC_ID_RC32KHZ);
osc_wait_ready(OSC_ID_RC32KHZ);
break;
case SYSCLK_SRC_XOSC:
osc_enable(OSC_ID_XOSC);
osc_wait_ready(OSC_ID_XOSC);
break;
#ifdef CONFIG_PLL0_SOURCE
case SYSCLK_SRC_PLL:
if (CONFIG_PLL0_SOURCE == PLL_SRC_RC2MHZ) {
need_rc2mhz = true;
}
pll_enable_config_defaults(0);
break;
#endif
default:
//unhandled_case(CONFIG_SYSCLK_SOURCE);
return;
}
ccp_write_io((uint8_t *)&CLK.CTRL, CONFIG_SYSCLK_SOURCE);
Assert(CLK.CTRL == CONFIG_SYSCLK_SOURCE);
#ifdef CONFIG_OSC_AUTOCAL
osc_enable_autocalibration(CONFIG_OSC_AUTOCAL,CONFIG_OSC_AUTOCAL_REF_OSC);
if (CONFIG_OSC_AUTOCAL == OSC_ID_RC2MHZ
|| CONFIG_OSC_AUTOCAL_REF_OSC == OSC_ID_RC2MHZ) {
need_rc2mhz = true;
}
#endif
if (!need_rc2mhz) {
osc_disable(OSC_ID_RC2MHZ);
}
}
}