Posted on May 25, 2014 at 05:11On the NUCLEO-F401RE, using the SystemClock_Config() funtion from the STM32F4xx-Nucleo template from the following file:
STM32Cube_FW_F4_V1.1.0\Projects\STM32F4xx-Nucleo\Templates\Src\main.c
I cannot get the HSI calibration trim value to change with the value in the following line (line 125):
RCC_OscInitStruct.HSICalibrationValue = 16;
I have tried all values from 0 to 31 and the actual HSI does not change, as determined by reading the RCC->CR and measuring the baud rate on the output from the USART2 Tx pin.
However, after the MCU initialization is complete, if I attempt to change the HSI calibration trim using the
__HAL_RCC_HSI_CALIBRATIONVALUE_ADJUST() macro, I can successfully change the HSI clock rate, again as determined by reading the RCC->CR and measuring the baud rate on the output from the USART2 Tx pin.
Is it possible the PLL configuation changes made later after the
__HAL_RCC_HSI_CALIBRATIONVALUE_ADJUST() macro call in
HAL_RCC_OscConfig() function in
stm32f4xx_hal_rcc.c affect the HSI calibration trim setting? It appears the HSI calibration trim is always being set to 16, the same as the value in the template.
NUCLEO-F401RESTM32F401RE
CPU ID: 0x410fc241
Implementer : 0x41
Variant : 0x0
Constant : 0xf
PartNo : 0xc24
Revision : 0x1
MCU ID: 0x10006433
Revision : 0x1000
Device : 0x433
HAL Version: 0x01000000
CMSIS Version: 0x02000000
#hsi #rcc #cubef4 #stm32cubef4-nucleo #hal
