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/**
* \file
*
* \brief Chip-specific system clock management functions.
*
* Copyright (c) 2011-2012 Atmel Corporation. All rights reserved.
*
* \asf_license_start
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
* Atmel microcontroller product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
#include <sysclk.h>
/// @cond 0
/**INDENT-OFF**/
#ifdef __cplusplus
extern "C" {
#endif
/**INDENT-ON**/
/// @endcond
/**
* \weakgroup sysclk_group
* @{
*/
#if defined(CONFIG_SYSCLK_DEFAULT_RETURNS_SLOW_OSC)
/**
* \brief boolean signalling that the sysclk_init is done.
*/
uint32_t sysclk_initialized = 0;
#endif
/**
* \brief Set system clock prescaler configuration
*
* This function will change the system clock prescaler configuration to
* match the parameters.
*
* \note The parameters to this function are device-specific.
*
* \param cpu_shift The CPU clock will be divided by \f$2^{mck\_pres}\f$
*/
void sysclk_set_prescalers(uint32_t ul_pres)
{
pmc_mck_set_prescaler(ul_pres);
SystemCoreClockUpdate();
}
/**
* \brief Change the source of the main system clock.
*
* \param src The new system clock source. Must be one of the constants
* from the <em>System Clock Sources</em> section.
*/
void sysclk_set_source(uint32_t ul_src)
{
switch (ul_src) {
case SYSCLK_SRC_SLCK_RC:
case SYSCLK_SRC_SLCK_XTAL:
case SYSCLK_SRC_SLCK_BYPASS:
pmc_mck_set_source(PMC_MCKR_CSS_SLOW_CLK);
break;
case SYSCLK_SRC_MAINCK_4M_RC:
case SYSCLK_SRC_MAINCK_8M_RC:
case SYSCLK_SRC_MAINCK_12M_RC:
case SYSCLK_SRC_MAINCK_XTAL:
case SYSCLK_SRC_MAINCK_BYPASS:
pmc_mck_set_source(PMC_MCKR_CSS_MAIN_CLK);
break;
case SYSCLK_SRC_PLLACK:
pmc_mck_set_source(PMC_MCKR_CSS_PLLA_CLK);
break;
case SYSCLK_SRC_UPLLCK:
pmc_mck_set_source(PMC_MCKR_CSS_UPLL_CLK);
break;
}
SystemCoreClockUpdate();
}
#if defined(CONFIG_USBCLK_SOURCE) || defined(__DOXYGEN__)
/**
* \brief Enable full speed USB clock.
*
* \note The SAM3X UDP hardware interprets div as div+1. For readability the hardware div+1
* is hidden in this implementation. Use div as div effective value.
*
* \param pll_id Source of the USB clock.
* \param div Actual clock divisor. Must be superior to 0.
*/
void sysclk_enable_usb(void)
{
Assert(CONFIG_USBCLK_DIV > 0);
switch (CONFIG_USBCLK_SOURCE) {
#ifdef CONFIG_PLL0_SOURCE
case USBCLK_SRC_PLL0: {
struct pll_config pllcfg;
pll_enable_source(CONFIG_PLL0_SOURCE);
pll_config_defaults(&pllcfg, 0);
pll_enable(&pllcfg, 0);
pll_wait_for_lock(0);
pmc_switch_udpck_to_pllack(CONFIG_USBCLK_DIV - 1);
pmc_enable_udpck();
break;
}
#endif
case USBCLK_SRC_UPLL: {
pmc_enable_upll_clock();
pmc_switch_udpck_to_upllck(CONFIG_USBCLK_DIV - 1);
pmc_enable_udpck();
break;
}
}
}
/**
* \brief Disable full speed USB clock.
*
* \note This implementation does not switch off the PLL, it just turns off the USB clock.
*/
void sysclk_disable_usb(void)
{
pll_disable(1);
}
#endif // CONFIG_USBCLK_SOURCE
void sysclk_init(void)
{
struct pll_config pllcfg;
/* Set a flash wait state depending on the new cpu frequency */
system_init_flash(sysclk_get_cpu_hz());
/* Config system clock setting */
switch (CONFIG_SYSCLK_SOURCE) {
case SYSCLK_SRC_SLCK_RC:
osc_enable(OSC_SLCK_32K_RC);
osc_wait_ready(OSC_SLCK_32K_RC);
pmc_switch_mck_to_sclk(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_SLCK_XTAL:
osc_enable(OSC_SLCK_32K_XTAL);
osc_wait_ready(OSC_SLCK_32K_XTAL);
pmc_switch_mck_to_sclk(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_SLCK_BYPASS:
osc_enable(OSC_SLCK_32K_BYPASS);
osc_wait_ready(OSC_SLCK_32K_BYPASS);
pmc_switch_mck_to_sclk(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_MAINCK_4M_RC:
/* Already running from SYSCLK_SRC_MAINCK_4M_RC */
break;
case SYSCLK_SRC_MAINCK_8M_RC:
osc_enable(OSC_MAINCK_8M_RC);
osc_wait_ready(OSC_MAINCK_8M_RC);
pmc_switch_mck_to_mainck(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_MAINCK_12M_RC:
osc_enable(OSC_MAINCK_12M_RC);
osc_wait_ready(OSC_MAINCK_12M_RC);
pmc_switch_mck_to_mainck(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_MAINCK_XTAL:
osc_enable(OSC_MAINCK_XTAL);
osc_wait_ready(OSC_MAINCK_XTAL);
pmc_switch_mck_to_mainck(CONFIG_SYSCLK_PRES);
break;
case SYSCLK_SRC_MAINCK_BYPASS:
osc_enable(OSC_MAINCK_BYPASS);
osc_wait_ready(OSC_MAINCK_BYPASS);
pmc_switch_mck_to_mainck(CONFIG_SYSCLK_PRES);
break;
#ifdef CONFIG_PLL0_SOURCE
case SYSCLK_SRC_PLLACK:
pll_enable_source(CONFIG_PLL0_SOURCE);
pll_config_defaults(&pllcfg, 0);
pll_enable(&pllcfg, 0);
pll_wait_for_lock(0);
pmc_switch_mck_to_pllack(CONFIG_SYSCLK_PRES);
break;
#endif
case SYSCLK_SRC_UPLLCK:
pll_enable_source(CONFIG_PLL1_SOURCE);
pll_config_defaults(&pllcfg, 1);
pll_enable(&pllcfg, 1);
pll_wait_for_lock(1);
pmc_switch_mck_to_upllck(CONFIG_SYSCLK_PRES);
break;
}
/* Update the SystemFrequency variable */
SystemCoreClockUpdate();
#if (defined CONFIG_SYSCLK_DEFAULT_RETURNS_SLOW_OSC)
/* Signal that the internal frequencies are setup */
sysclk_initialized = 1;
#endif
}
//! @}
/// @cond 0
/**INDENT-OFF**/
#ifdef __cplusplus
}
#endif
/**INDENT-ON**/
/// @endcond