rt-thread/bsp/at32/at32f407-start/board/src/board.c

/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2022-03-08     shelton      first version
 */

#include "board.h"

void system_clock_config(void)
{
  /* reset crm */
  crm_reset();

  crm_clock_source_enable(CRM_CLOCK_SOURCE_HEXT, TRUE);

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

  /* config pll clock resource */
  crm_pll_config(CRM_PLL_SOURCE_HEXT_DIV, CRM_PLL_MULT_50, CRM_PLL_OUTPUT_RANGE_GT72MHZ);

  /* config hext division */
  crm_hext_clock_div_set(CRM_HEXT_DIV_2);

  /* 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 */
  crm_apb2_div_set(CRM_APB2_DIV_2);

  /* config apb1clk */
  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();
}