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Improves micros() accuracy using SysTick COUNTFLAG #202

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Merged
merged 2 commits into from
Jan 18, 2018
Merged

Improves micros() accuracy using SysTick COUNTFLAG #202

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1e9303c
clean unuseful comments
fpistm Jan 16, 2018
15dc04b
Improves micros() accuracy using SysTick COUNTFLAG
fpistm Jan 16, 2018
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83 changes: 8 additions & 75 deletions cores/arduino/stm32/clock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,84 +35,28 @@
*
******************************************************************************
*/
/** @addtogroup CMSIS
* @{
*/

/** @addtogroup stm32f4xx_system
* @{
*/

/** @addtogroup STM32F4xx_System_Private_Includes
* @{
*/
#include "stm32_def.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
* @}
*/

/** @addtogroup STM32F4xx_System_Private_TypesDefinitions
* @{
*/

/**
* @}
*/

/** @addtogroup STM32F4xx_System_Private_Defines
* @{
*/

/**
* @}
*/

/** @addtogroup STM32F4xx_System_Private_Macros
* @{
*/

/**
* @}
*/

/** @addtogroup STM32F4xx_System_Private_Variables
* @{
*/

/**
* @}
*/

/** @addtogroup STM32F4xx_System_Private_FunctionPrototypes
* @{
*/

/**
* @}
*/

/**
* @brief Function called to read the current micro second
* @param None
* @retval None
*/
uint32_t GetCurrentMicro(void)
{
uint32_t m0 = HAL_GetTick();
uint32_t u0 = SysTick->LOAD - SysTick->VAL;
uint32_t m1 = HAL_GetTick();
uint32_t u1 = SysTick->LOAD - SysTick->VAL;

if (m1 > m0) {
return ( m1 * 1000 + (u1 * 1000) / SysTick->LOAD);
} else {
return ( m0 * 1000 + (u0 * 1000) / SysTick->LOAD);
/* Ensure COUNTFLAG is reset by reading SysTick control and status register */
LL_SYSTICK_IsActiveCounterFlag();
uint32_t m = HAL_GetTick();
uint32_t u = SysTick->LOAD - SysTick->VAL;
if(LL_SYSTICK_IsActiveCounterFlag()) {
m = HAL_GetTick();
u = SysTick->LOAD - SysTick->VAL;
}
return ( m * 1000 + (u * 1000) / SysTick->LOAD);
}

/**
Expand Down Expand Up @@ -176,17 +120,6 @@ void delayInsideIT(uint32_t delay_us)
#endif
}

/**
* @}
*/

/**
* @}
*/

/**
* @}
*/
#ifdef __cplusplus
}
#endif
Expand Down