Making a input pulse counter with Timer peripheral in STM32F429-Discovery - timer

Question

I would to like to count pulses using timer peripheral TIM in a STM32F429I-Disco board. I have initialized the TIM3 as:
TIM_SlaveConfigTypeDef sSlaveConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim3.Instance = TIM3;
htim3.Init.Prescaler = 0;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 1000;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
HAL_TIM_Base_Init(&htim3);
sSlaveConfig.SlaveMode = TIM_SLAVEMODE_EXTERNAL1;
sSlaveConfig.InputTrigger = TIM_TS_TI2FP2;
sSlaveConfig.TriggerPolarity = TIM_TRIGGERPOLARITY_RISING;
sSlaveConfig.TriggerFilter = 15;
HAL_TIM_SlaveConfigSynchronization(&htim3, &sSlaveConfig);
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig);
and in the MSP it's like this:
if (htim->Instance == TIM3)
{
GPIO_InitTypeDef GPIO_InitStruct;
__TIM3_CLK_ENABLE();
GPIO_InitStruct.Pin = GPIO_PIN_4;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF2_TIM3;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}
I understand that it's a timer set in the pin PB4 and that it's triggered by pulses in this pin.
What I would like is to count this pulses, something like this:
while(1)
{
uint8_t buffer[128];
int numberSize = snprintf((char*)buffer, 128, "%d",(int) __HAL_TIM_GetCounter(&htim3));
writeStrOnCell(buffer, numberSize, 0, 0);
HAL_Delay(500);
}
But nothing is working...I'm not getting the pulses. I connect the PB4 to PA0 that is high when I push the user button.
Thanks

Answer 1

Probably you forgot to configure NVIC.
Example:
HAL_NVIC_SetPriority(TIM3_IRQn, 0, 1);
HAL_NVIC_EnableIRQ(TIMx_IRQn);
Notice that in this example the timer has quite high interrupt priority.