Issue with stm32l433 configuring HSI

[Nico_S]

Hi,

I have a stm32l433 chip and i'm using the internal RC Oszilator HSI.

My issue was that code generated straigth from cubemx turned the chip to run too fast, my HalTick was like 1.2 Khz instead of 1kHz.

Now i tracked the error down to a bad configuration of the HSI trim registers within the HAL libraries. Followed listed what i've found:

RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;

This one gets the default value from stm32l433xx.h which says;

#if defined(RCC_ICSCR_HSITRIM_6)
#define RCC_HSICALIBRATION_DEFAULT     0x40U         /*!< Default HSI calibration trimming value 64 on devices other than STM32L47x/STM32L48x */
#else
#define RCC_HSICALIBRATION_DEFAULT     0x10U         /*!< Default HSI calibration trimming value 16 on STM32L47x/STM32L48x devices */
#endif /* RCC_ICSCR_HSITRIM_6 */

Now this RCC_ICSCR_HSITRIM_6 is beeing defined so it takes the 0x40U.

So this checks if HSITRIM is 7 bits wide. which is according datasheet correct:

 

Now i see the reset value should be 0x40xx 00xx. When i check this register after POR it has a value of 0x10xx00xx. Strange..

So if i now set:

RCC_OscInitStruct.HSICalibrationValue = 0x10;

then the chip runs exactly at my desired speed.....

So that says either:

• Datasheet RM0394 and HAL is wrong

or:

• CHIP STM32L433CCU6 has a bug..

Did i miss something?

Cheers

[Uwe Bonnes]

I would suspect that HAL is wrong...

[Imen.D · Accepted solution]

Hello @Nico_S​ ,

Welcome to the STM32 Community 😊 and thanks for pointing out this issue.

The problem comes from the HAL and the RM0394 Rev4 as you said.

This has been raised to the appropriate team for fix:

1. RM0394 should be updated for STM32L43x/STM32L44x devices HSITRIM range.

2. The fix in HAL is planned and will be integrated soon. So, keep an eye out for the coming update.

• Correction in CMSIS Device files: stm32l431xx.h / stm32l432xx.h / stm32l433xx.h / stm32l442xx.h / stm32l443xx.h

/*!< HSITRIM configuration */
#define RCC_ICSCR_HSITRIM_Pos                (24U)
#define RCC_ICSCR_HSITRIM_Msk                (0x1FUL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x1F000000 */
#define RCC_ICSCR_HSITRIM                    RCC_ICSCR_HSITRIM_Msk             /*!< HSITRIM[4:0] bits */
#define RCC_ICSCR_HSITRIM_0                  (0x01UL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x01000000 */
#define RCC_ICSCR_HSITRIM_1                  (0x02UL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x02000000 */
#define RCC_ICSCR_HSITRIM_2                  (0x04UL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x04000000 */
#define RCC_ICSCR_HSITRIM_3                  (0x08UL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x08000000 */
#define RCC_ICSCR_HSITRIM_4                  (0x10UL << RCC_ICSCR_HSITRIM_Pos) /*!< 0x10000000 */

• Correction in HAL RCC file: stm32l4xx_hal_rcc.h

#if defined(RCC_ICSCR_HSITRIM_6)
#define RCC_HSICALIBRATION_DEFAULT     0x40U         /*!< Default HSI calibration trimming value 64 on devices other than STM32L43x/STM32L44x/STM32L47x/STM32L48x */
#else
#define RCC_HSICALIBRATION_DEFAULT     0x10U         /*!< Default HSI calibration trimming value 16 on STM32L43x/STM32L44x/STM32L47x/STM32L48x devices */
#endif /* RCC_ICSCR_HSITRIM_6 */

• stm32l4xx_ll_rcc.h (only comments)

/**
  * @brief  Set HSI Calibration trimming
  * @note user-programmable trimming value that is added to the HSICAL
  * @note Default value is 16 on STM32L43x/STM32L44x/STM32L47x/STM32L48x or 64 on other devices,
  *       which, when added to the HSICAL value, should trim the HSI to 16 MHz +/- 1 %
  * @rmtoll ICSCR        HSITRIM       LL_RCC_HSI_SetCalibTrimming
  * @param  Value Between Min_Data = 0 and Max_Data = 31 on STM32L43x/STM32L44x/STM32L47x/STM32L48x or
  *               between Min_Data = 0 and Max_Data = 127 on other devices
  * @retval None
  */
__STATIC_INLINE void LL_RCC_HSI_SetCalibTrimming(uint32_t Value)
{
  MODIFY_REG(RCC->ICSCR, RCC_ICSCR_HSITRIM, Value << RCC_ICSCR_HSITRIM_Pos);
}
 
/**
  * @brief  Get HSI Calibration trimming
  * @rmtoll ICSCR        HSITRIM       LL_RCC_HSI_GetCalibTrimming
  * @retval Between Min_Data = 0 and Max_Data = 31 on STM32L43x/STM32L44x/STM32L47x/STM32L48x or
  *         between Min_Data = 0 and Max_Data = 127 on other devices
  */
__STATIC_INLINE uint32_t LL_RCC_HSI_GetCalibTrimming(void)
{
  return (uint32_t)(READ_BIT(RCC->ICSCR, RCC_ICSCR_HSITRIM) >> RCC_ICSCR_HSITRIM_Pos);
}

Imen