# 2MHz system clock
CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=2000000

# SYSCLK selection
CONFIG_CLOCK_STM32_SYSCLK_SRC_MSI=y
# produce 2MHz clock at MSI RC output
CONFIG_CLOCK_STM32_MSI_RANGE=5
# select buses prescalers
CONFIG_CLOCK_STM32_AHB_PRESCALER=1
CONFIG_CLOCK_STM32_APB1_PRESCALER=1
CONFIG_CLOCK_STM32_APB2_PRESCALER=1