134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/**
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**************************************************************************
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* @file at32f403_clock.c
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* @brief system clock config program
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**************************************************************************
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* Copyright notice & Disclaimer
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*
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* The software Board Support Package (BSP) that is made available to
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* download from Artery official website is the copyrighted work of Artery.
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* Artery authorizes customers to use, copy, and distribute the BSP
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* software and its related documentation for the purpose of design and
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* development in conjunction with Artery microcontrollers. Use of the
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* software is governed by this copyright notice and the following disclaimer.
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*
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* THIS SOFTWARE IS PROVIDED ON "AS IS" BASIS WITHOUT WARRANTIES,
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* GUARANTEES OR REPRESENTATIONS OF ANY KIND. ARTERY EXPRESSLY DISCLAIMS,
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* TO THE FULLEST EXTENT PERMITTED BY LAW, ALL EXPRESS, IMPLIED OR
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* STATUTORY OR OTHER WARRANTIES, GUARANTEES OR REPRESENTATIONS,
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* INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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*
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**************************************************************************
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*/
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/* includes ------------------------------------------------------------------*/
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#include "at32f403_clock.h"
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/** @addtogroup AT32F403_periph_template
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* @{
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*/
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/** @addtogroup 403_System_clock_configuration System_clock_configuration
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* @{
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*/
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/**
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* @brief delay to wait for stable.
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* @note this function should be used before reading stable flag.
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* @param none
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* @retval none
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*/
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static void wait_stbl(uint32_t delay)
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{
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volatile uint32_t i;
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for(i = 0; i < delay; i++);
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}
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/**
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* @brief system clock config program
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* @note the system clock is configured as follow:
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* system clock (sclk) = hext / 2 * pll_mult
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* system clock source = pll (hext)
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* - hext = HEXT_VALUE
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* - sclk = 192000000
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* - ahbdiv = 1
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* - ahbclk = 192000000
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* - apb2div = 2
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* - apb2clk = 96000000
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* - apb1div = 2
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* - apb1clk = 96000000
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* - pll_mult = 48
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* - pll_range = GT72MHZ (greater than 72 mhz)
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* @param none
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* @retval none
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*/
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void system_clock_config(void)
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{
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/* reset crm */
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crm_reset();
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crm_clock_source_enable(CRM_CLOCK_SOURCE_HEXT, TRUE);
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/* wait for hext stable */
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wait_stbl(HEXT_STABLE_DELAY);
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/* wait till hext is ready */
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while(crm_hext_stable_wait() == ERROR)
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{
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}
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/* config pll clock resource */
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crm_pll_config(CRM_PLL_SOURCE_HEXT_DIV, CRM_PLL_MULT_48, CRM_PLL_OUTPUT_RANGE_GT72MHZ);
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/* enable pll */
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crm_clock_source_enable(CRM_CLOCK_SOURCE_PLL, TRUE);
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/* wait till pll is ready */
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while(crm_flag_get(CRM_PLL_STABLE_FLAG) != SET)
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{
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}
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/* config apb2clk, the maximum frequency of APB1/APB2 clock is 100 MHz */
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crm_apb2_div_set(CRM_APB2_DIV_2);
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/* config apb1clk, the maximum frequency of APB1/APB2 clock is 100 MHz */
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crm_apb1_div_set(CRM_APB1_DIV_2);
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/* 1step: config ahbclk div8 */
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crm_ahb_div_set(CRM_AHB_DIV_8);
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/* select pll as system clock source */
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crm_sysclk_switch(CRM_SCLK_PLL);
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/* wait till pll is used as system clock source */
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while(crm_sysclk_switch_status_get() != CRM_SCLK_PLL)
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{
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}
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/* delay */
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wait_stbl(PLL_STABLE_DELAY);
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/* 2step: config ahbclk div2 */
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crm_ahb_div_set(CRM_AHB_DIV_2);
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/* delay */
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wait_stbl(PLL_STABLE_DELAY);
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/* 3step: config ahbclk to target div */
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crm_ahb_div_set(CRM_AHB_DIV_1);
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/* update system_core_clock global variable */
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system_core_clock_update();
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}
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/**
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* @}
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*/
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/**
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* @}
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*/
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