STM32F373 Input Capture
According to the datasheet PB0 AF2 is TIM3_CH3 and not TIM3_CH2. I would change to this:

TIM_ICInitStruct.TIM_Channel=TIM_Channel_3;
TIM_ICInitStruct.TIM_ICPolarity=TIM_ICPolarity_Rising;
TIM_ICInitStruct.TIM_ICSelection=TIM_ICSelection_DirectTI;
TIM_ICInit(TIM3,&amp;TIM_ICInitStruct);


Or just change to AF10 for PB0 (which happens to be PB0 TIM3_CH2):

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_0;
GPIO_PinAFConfig(GPIOB,GPIO_PinSource0,GPIO_AF_10);
GPIO_Init(GPIOB,&amp;GPIO_InitStructure);