STM32F7 Timer triggers Timer - c

Question

I generated some code with CubeMX. I want that timer 2 is triggering timer 3. If an overflow on Timer 2 occurs, Timer 3 should count up 1. I tried some configurations but nothing worked - no interrupt on timer3 when I set the output trigger (timer 2)
sMasterConfig.MasterOutputTrigger
to the same value as (timer 3)
sSlaveConfig.SlaveMode
I have still no interrupt on timer 3
This is the full configurationcode from both Timers:
TIM_HandleTypeDef htim2;
TIM_HandleTypeDef htim3;
/* TIM2 init function */
void MX_TIM2_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim2.Instance = TIM2;
htim2.Init.Prescaler = 54;
htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
htim2.Init.Period = 250;
htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV4;
htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_ENABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
/* TIM3 init function */
void MX_TIM3_Init(void)
{
TIM_SlaveConfigTypeDef sSlaveConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim3.Instance = TIM3;
htim3.Init.Prescaler = 1;
htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
htim3.Init.Period = 8000;
htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sSlaveConfig.SlaveMode = TIM_SLAVEMODE_EXTERNAL1;
sSlaveConfig.InputTrigger = TIM_TS_ITR0;
if (HAL_TIM_SlaveConfigSynchronization(&htim3, &sSlaveConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}

Answer 1

Config structs should be initialized.
void MX_TIM2_Init(void)
{
TIM_ClockConfigTypeDef sClockSourceConfig;
Structures defined in a function body will not be initialized, fields not explicitly initialized will get some unpredictable value.
TIM_ClockConfigTypeDef sClockSourceConfig = {};
Using this form will explicitly zero all fields before use.
Wrong input trigger
sSlaveConfig.InputTrigger = TIM_TS_ITR0;
Using ITR0 makes TIM3 a slave of TIM1. The correct value is TIM_TS_ITR1. See the TIMx internal trigger connection table at the end of the desciption of the TIMx slave mode control register TIMx_SMCR in the Reference Manual.
A working example without HAL
Well, it's still using a few useful macros from HAL.
void TIM3_IRQHandler(void) {
if(TIM3->SR & TIM_SR_UIF) {
TIM3->SR = ~TIM_SR_UIF;
do_something();
}
}
void starttimers(void) {
NVIC_EnableIRQ(TIM3_IRQn);
__HAL_RCC_TIM2_CLK_ENABLE();
__HAL_RCC_TIM3_CLK_ENABLE();
TIM3->ARR = 8000; // slave timer period
// trigger selection TS=001 ITR1 = TIM2, slave mode SMS=0111 external clock mode 1
TIM3->SMCR = TIM_TS_ITR1 | TIM_SMCR_SMS_0 | TIM_SMCR_SMS_1 | TIM_SMCR_SMS_2;
TIM3->DIER = TIM_DIER_UIE; // interrupt on update event (timer overflow)
TIM3->CR1 = TIM_CR1_CEN; // enable timer 3
TIM2->PSC = 54; // prescaler preload
TIM2->EGR = TIM_EGR_UG; // update prescaler
TIM2->ARR = 250; // master timer period
TIM2->CR2 = TIM_TRGO_UPDATE; // master mode selection MMS=010 Update event
TIM2->CR1 = TIM_CR1_CEN; // enable timer 2
}