Hi-
Following up, here is how I set up the TIM8 on a STM32G431C8x. This all seems to work. I am using the TIM8_CH3 as my second input but the trigger actually comes internally. I have a firmware signal for which I look for a zero crossing, and if it occurs I execute this line:
/* add 'limiting' function that gives square-wave */
uint16_t limited;
if(y0 > 0) limited = 3048;
else limited = 1048;
/** capture counter & trigger DMA1_CH2 if positive crossing
* this generates interrupt for phase detector to do processing.
*/
if( (limited == 3048) && (old_limit == 1048))
TIM8->EGR |= TIM_EGR_CC3G ;
Here is how I set up TIM8 and DMA:
#define PHASE_DETECT
#ifdef PHASE_DETECT
{
/* TIM8_CH1 is capture/compare from input pin and
TIM8_CH3 is capture/compare FW triggered by TIM8_EGR.CCG3
*/
/* enable TIM8 DMA interrupts */
TIM8->DIER |= (TIM_DIER_CC3DE | TIM_DIER_CC1DE) ;
/* enable TIM8 capture / compare */
TIM8->CCER |= ( TIM_CCER_CC1E | TIM_CCER_CC3E ) ;
/* enable TIM8 */
TIM8->CR1 |= TIM_CR1_CEN;
}
/**
* @brief TIM8 Initialization Function
* @param None
* @retval None
*/
static void MX_TIM8_Init(void)
{
/* USER CODE BEGIN TIM8_Init 0 */
/* USER CODE END TIM8_Init 0 */
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_IC_InitTypeDef sConfigIC = {0};
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};
/* USER CODE BEGIN TIM8_Init 1 */
/* USER CODE END TIM8_Init 1 */
htim8.Instance = TIM8;
htim8.Init.Prescaler = 32;
htim8.Init.CounterMode = TIM_COUNTERMODE_UP;
htim8.Init.Period = 48000;
htim8.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim8.Init.RepetitionCounter = 0;
htim8.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_IC_Init(&htim8) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim8, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigIC.ICPolarity = TIM_INPUTCHANNELPOLARITY_RISING;
sConfigIC.ICSelection = TIM_ICSELECTION_DIRECTTI;
sConfigIC.ICPrescaler = TIM_ICPSC_DIV1;
sConfigIC.ICFilter = 0;
if (HAL_TIM_IC_ConfigChannel(&htim8, &sConfigIC, TIM_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
if (HAL_TIM_IC_ConfigChannel(&htim8, &sConfigIC, TIM_CHANNEL_3) != HAL_OK)
{
Error_Handler();
}
sBreakDeadTimeConfig.BreakAFMode = TIM_BREAK_AFMODE_INPUT;
sBreakDeadTimeConfig.Break2AFMode = TIM_BREAK_AFMODE_INPUT;
if (HAL_TIMEx_ConfigBreakDeadTime(&htim8, &sBreakDeadTimeConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM8_Init 2 */
/* USER CODE END TIM8_Init 2 */
}
and the DMA config:
static void DMA_Config(void)
{
/*##-2a- Select the DMA functional Parameters for TIM8 chan1 ######################*/
hdma_tim8_ch1.Init.Direction = DMA_PERIPH_TO_MEMORY; /* M2M transfer mode */
hdma_tim8_ch1.Init.PeriphInc = DMA_PINC_DISABLE; /* Peripheral increment mode Enable */
hdma_tim8_ch1.Init.MemInc = DMA_MINC_DISABLE; /* Memory increment mode Enable */
hdma_tim8_ch1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD; /* Peripheral data alignment : Word */
hdma_tim8_ch1.Init.MemDataAlignment = DMA_MDATAALIGN_WORD; /* memory data alignment : Word */
hdma_tim8_ch1.Init.Mode = DMA_CIRCULAR; /* Normal DMA mode */
hdma_tim8_ch1.Init.Priority = DMA_PRIORITY_HIGH; /* priority level : high */
/*##-2b- Select the DMA functional Parameters for TIM8 chan3 ######################*/
hdma_tim8_ch3.Init.Direction = DMA_PERIPH_TO_MEMORY; /* M2M transfer mode */
hdma_tim8_ch3.Init.PeriphInc = DMA_PINC_DISABLE; /* Peripheral increment mode Enable */
hdma_tim8_ch3.Init.MemInc = DMA_MINC_DISABLE; /* Memory increment mode Enable */
hdma_tim8_ch3.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD; /* Peripheral data alignment : Word */
hdma_tim8_ch3.Init.MemDataAlignment = DMA_MDATAALIGN_WORD; /* memory data alignment : Word */
hdma_tim8_ch3.Init.Mode = DMA_CIRCULAR; /* Normal DMA mode */
hdma_tim8_ch3.Init.Priority = DMA_PRIORITY_HIGH; /* priority level : high */
/* ##-3- Select the DMA instance to be used for the transfers # */
/* TIM8 ch1 is DMA ch 1 */
hdma_tim8_ch1.Instance = DMA1_Channel1;
/* TIM8 ch3 is DMA ch 2 */
hdma_tim8_ch3.Instance = DMA1_Channel2;
/*##-4- Initialize the DMA channel ##########################################*/
if (HAL_DMA_Init(&hdma_tim8_ch1) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
if (HAL_DMA_Init(&hdma_tim8_ch3) != HAL_OK)
{
/* Initialization Error */
Error_Handler();
}
/*##-5- Select Callbacks functions called after Transfer complete and Transfer error */
HAL_DMA_RegisterCallback(&hdma_tim8_ch1, HAL_DMA_XFER_CPLT_CB_ID, TransferCompleteRef);
HAL_DMA_RegisterCallback(&hdma_tim8_ch3, HAL_DMA_XFER_CPLT_CB_ID, TransferCompleteFb);
HAL_DMA_RegisterCallback(&hdma_tim8_ch1, HAL_DMA_XFER_ERROR_CB_ID, TransferErrorRef);
HAL_DMA_RegisterCallback(&hdma_tim8_ch3, HAL_DMA_XFER_ERROR_CB_ID, TransferErrorFb);
/*##-6- Configure NVIC for DMA transfer complete/error interrupts ##########*/
/* Set Interrupt Group Priority */
HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 3, 2); /* sets intr # and priority */
HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn); /* enables intr */
HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 3, 2); /* sets intr # and priority */
HAL_NVIC_EnableIRQ(DMA1_Channel2_IRQn); /* enables intr */
/*##-7- Start the DMA transfers using the interrupt mode ####################*/
/* Configure the source, destination and buffer size DMA fields and Start DMA transfer */
/* Enable All the DMA interrupts */
if (HAL_DMA_Start_IT(&hdma_tim8_ch1, (uint32_t)&TIM8->CCR1, (uint32_t)&buffer1, BUFFER_SIZE) != HAL_OK)
{
/* Transfer Error */
Error_Handler();
}
if (HAL_DMA_Start_IT(&hdma_tim8_ch3, (uint32_t)&TIM8->CCR3, (uint32_t)&buffer2, BUFFER_SIZE) != HAL_OK)
{
/* Transfer Error */
Error_Handler();
}
}
