82 lines
2.8 KiB
C
82 lines
2.8 KiB
C
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#include "system_dwt.h"
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#define DWT_CR *(volatile uint32_t *)0xE0001000
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#define DWT_CYCCNT *(volatile uint32_t *)0xE0001004
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#define DEM_CR *(volatile uint32_t *)0xE000EDFC
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#define DEM_CR_TRCENA_EN (1 << 24)
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#define DWT_CR_CYCCNTENA (1 << 0)
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/************************************************************
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* @brief 系统dwt周期性计时器初始化
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* @param NULL
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* @return 时钟周期计数器计数值
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* @author LH
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* @date 2020-05-19
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***********************************************************/
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uint8_t system_dwt_init(void)
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{
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DEM_CR |= (uint32_t)DEM_CR_TRCENA_EN; /* 使能DWT外设 */
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DWT_CYCCNT = (uint32_t)0u;
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DWT_CR |= (uint32_t)DWT_CR_CYCCNTENA;
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__ASM volatile ("NOP");
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__ASM volatile ("NOP");
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__ASM volatile ("NOP"); //执行3条空指令
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return (DWT_CYCCNT)?0:1; //检查时钟周期计数器是否已经启动
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}
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/************************************************************
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* @brief 获取时钟周期计数器计数值
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* @param NULL
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* @return 计数值
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* @author LH
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* @date 2020-05-19
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***********************************************************/
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uint32_t get_system_dwt_value(void)
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{
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return ((uint32_t)DWT_CYCCNT);
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}
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/************************************************************
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* @brief 通过dwt周期计数器延时us 主频96MHz的情况下，32位计数器计满是2^32/96000000 = 44.739秒 建议使用本函数做延迟的话，延迟在1秒以下。
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* @param delay_time/us 延迟长度，单位1us
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* @return
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* @author LH
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* @date 2020-05-19
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***********************************************************/
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void dwt_delay_us(uint32_t delay_time)
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{
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uint32_t temp_cnt, delay_cnt;
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uint32_t start_time;
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start_time = DWT_CYCCNT; /* 刚进入时的计数器值 */
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temp_cnt = 0;
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//delay_cnt = delay_time * (system_get_clock() / 1000000); /* 需要的节拍数 */
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while(temp_cnt < delay_cnt)
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{
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temp_cnt = DWT_CYCCNT - start_time; /* 求减过程中，如果发生第一次32位计数器重新计数，依然可以正确计算 */
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}
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}
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/************************************************************
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* @brief 通过dwt周期计数器延时计数节拍
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* @param delay_time
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* @return
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* @author LH
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* @date 2020-05-19
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***********************************************************/
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void dwt_delay_tick(uint32_t tick)
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{
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uint32_t temp_cnt, delay_cnt;
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uint32_t start_time;
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temp_cnt = 0;
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delay_cnt = tick; /* 需要的节拍数 */
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start_time = DWT_CYCCNT; /* 刚进入时的计数器值 */
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while(temp_cnt < delay_cnt)
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{
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temp_cnt = DWT_CYCCNT - start_time; /* 求减过程中，如果发生第一次32位计数器重新计数，依然可以正确计算 */
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}
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}
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