RCC HSI calibration register
| HSICAL | HSI clock calibration Set by hardware by option byte loading during system reset nreset. Adjusted by software through trimming bits HSITRIM. This field represents the sum of engineering option byte calibration value and HSITRIM bits value. |
| HSITRIM | HSI clock trimming Set by software to adjust calibration. HSITRIM field is added to the engineering option bytes loaded during reset phase (FLASH_HSI_OPT) in order to form the calibration trimming value. HSICAL = HSITRIM + FLASH_HSI_OPT. After a change of HSITRIM it takes one system clock cycle before the new HSITRIM value is updated Note: The reset value of the field is 0x40. |