STM32L0固件库error

[woniu2211]

IAR环境：库文件stm32l0xx_ll_rcc.h中RCC_CSR_OBLRSTF出现未定义报错，请教高手，谢谢！

__STATIC_INLINE uint32_t LL_RCC_IsActiveFlag_OBLRST(void)
{
return (READ_BIT(RCC->CSR, RCC_CSR_OBLRSTF) == (RCC_CSR_OBLRSTF));
}