tinyUSB/hw/bsp/at32f402_405/at32f402_405_clock.c

/**
  **************************************************************************
  * @file     at32f402_405_clock.c
  * @brief    system clock config program
  **************************************************************************
  *                       Copyright notice & Disclaimer
  *
  * The software Board Support Package (BSP) that is made available to
  * download from Artery official website is the copyrighted work of Artery.
  * Artery authorizes customers to use, copy, and distribute the BSP
  * software and its related documentation for the purpose of design and
  * development in conjunction with Artery microcontrollers. Use of the
  * software is governed by this copyright notice and the following disclaimer.
  *
  * THIS SOFTWARE IS PROVIDED ON "AS IS" BASIS WITHOUT WARRANTIES,
  * GUARANTEES OR REPRESENTATIONS OF ANY KIND. ARTERY EXPRESSLY DISCLAIMS,
  * TO THE FULLEST EXTENT PERMITTED BY LAW, ALL EXPRESS, IMPLIED OR
  * STATUTORY OR OTHER WARRANTIES, GUARANTEES OR REPRESENTATIONS,
  * INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  *
  **************************************************************************
  */

/* includes ------------------------------------------------------------------*/
#include "at32f402_405_clock.h"

/**
  * @brief  system clock config program
  * @note   the system clock is configured as follow:
  *         system clock (sclk)   = (hext * pll_ns)/(pll_ms * pll_fp)
  *         system clock source   = pll (hext)
  *         - hext                = HEXT_VALUE
  *         - sclk                = 216000000
  *         - ahbdiv              = 1
  *         - ahbclk              = 216000000
  *         - apb2div             = 1
  *         - apb2clk             = 216000000
  *         - apb1div             = 2
  *         - apb1clk             = 108000000
  *         - pll_ns              = 72
  *         - pll_ms              = 1
  *         - pll_fr              = 4
  *         - flash_wtcyc         = 6 cycle
  * @param  none
  * @retval none
  */
void system_clock_config(void)
{
  /* reset crm */
  crm_reset();

  /* config flash psr register */
  flash_psr_set(FLASH_WAIT_CYCLE_6);

  /* enable pwc periph clock */
  crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);

  /* set power ldo output voltage to 1.3v */
  pwc_ldo_output_voltage_set(PWC_LDO_OUTPUT_1V3);

  crm_clock_source_enable(CRM_CLOCK_SOURCE_HEXT, TRUE);

  /* wait till hext is ready */
  while(crm_hext_stable_wait() == ERROR)
  {
  }

  /* if pll parameter has changed, please use the AT32_New_Clock_Configuration tool for new configuration. */
  crm_pll_config(CRM_PLL_SOURCE_HEXT, 72, 1, CRM_PLL_FP_4);

  /* config pllu div */
  crm_pllu_div_set(CRM_PLL_FU_18);

  /* enable pll */
  crm_clock_source_enable(CRM_CLOCK_SOURCE_PLL, TRUE);

  /* wait till pll is ready */
  while(crm_flag_get(CRM_PLL_STABLE_FLAG) != SET)
  {
  }

  /* config ahbclk */
  crm_ahb_div_set(CRM_AHB_DIV_1);

  /* config apb2clk, the maximum frequency of APB2 clock is 216 MHz */
  crm_apb2_div_set(CRM_APB2_DIV_1);

  /* config apb1clk, the maximum frequency of APB1 clock is 120 MHz */
  crm_apb1_div_set(CRM_APB1_DIV_2);

  /* enable auto step mode */
  crm_auto_step_mode_enable(TRUE);

  /* select pll as system clock source */
  crm_sysclk_switch(CRM_SCLK_PLL);

  /* wait till pll is used as system clock source */
  while(crm_sysclk_switch_status_get() != CRM_SCLK_PLL)
  {
  }

  /* disable auto step mode */
  crm_auto_step_mode_enable(FALSE);

  /* update system_core_clock global variable */
  system_core_clock_update();

#ifdef AT32F405xx
  /*
    AT32405 OTGHS PHY not initialized, resulting in high power consumption
    Solutions:
    1. If OTGHS is not used, call the "reduce_power_consumption" function to reduce power consumption.
       PLL or HEXT should be enabled when calling this function.
       Example: reduce_power_consumption();

    2. If OTGHS is required, initialize OTGHS to reduce power consumption, without the need to call this function.

       for more detailed information. please refer to the faq document FAQ0148.
  */
#endif

#ifdef AT32F402xx
  /* reduce power consumption */
  reduce_power_consumption();
#endif
}