Using TIM6 and TIM2 in STM32f407 Discovery board: DHT11 sensor and CAN frames

[Azizz]

Hello everyone,

I'm using the STM32f407 Discovery board.
I'm trying to use TIM2 to send a frame in a cyclic way and also i'm using TIM6 to send the data of a DHT11 sensor. The problem is that when i added the TIM6 i no longer receiver the frames.
Who should i adjust my code in order to work with the DHT11 sensor data and still send my frames.
I tried to use the DHT11 sensor separately to make sure that the code works and it works perfectly.

[mƎALLEm]

Hello,

First, could you please state on this thread? if the provided answer solved your issue please accept it as solution.

Second, 

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@Azizz wrote:

The problem is that when i added the TIM6 i no longer receiver the frames.

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Which frame? CAN frames? if yes from which node?

[Azizz]

The problem occurs in these lines 

 if (HAL_TIM_Base_Start_IT(&htim2) != HAL_OK)
 {
 Error_Handler();
 }

 HAL_TIM_OC_Start_IT(&htim2, TIM_CHANNEL_1);

I cannot send any frame neither the cyclic one or the frame sent by request.

[Andrew Neil]

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@Azizz wrote:

The problem occurs in these lines 

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What problem occurs, exactly?

Does it hit the Error-Handler ?

If so, look at what value HAL_TIM_Base_Start_IT returned; step into it to find why ...

 

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@Azizz wrote:

when i added the TIM6 i no longer receiver the frames.

---

Is that because nothing is transmitted at all, or the transmission becomes "bad"?

If "bad", in what way(s) is it bad?

 

PS:

 

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@Azizz wrote:

I'm trying to use TIM2 to send a frame in a cyclic way and also i'm using TIM6 to send the data of a DHT11 sensor. The problem is that when i added the TIM6 i no longer receiver the frames.

---

If you just start TIM6 without doing any DHT11 stuff, are the [CAN?] frames still OK

ie, is it the timer itself, or something else in your DHT11 code that's causing the problem?

[Azizz]

Yess when i remove the line commented i receive the frames

void Send_Cyclic_Frame_A (void) {
	uint8_t temp = 0, humi = 0;

 //DHT11_GetData(&temp, &humi);

	TxHeader.StdId = 0x103;
	TxHeader.RTR = CAN_RTR_DATA;
	TxHeader.IDE = CAN_ID_STD;
	TxHeader.DLC = 2;
	TxHeader.TransmitGlobalTime = DISABLE;

	TxData[0] = temp;
	TxData[1] = humi;

	if (HAL_CAN_AddTxMessage(&hcan1, &TxHeader, TxData, &TxMailbox)!= HAL_OK )
	{
		 Error_Handler();
	}
}

[Azizz]

It is not transmitted at all and when i remove these lines the program works but the frame is no longer send cyclically.
It doesn't hit he error handler when i try to use the step over button in the line showed below, it blocks the program.

 if (HAL_TIM_Base_Start_IT(&htim2) != HAL_OK)

[Andrew Neil]

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@Azizz wrote:

 when i try to use the step over button in the line showed below, it blocks the program.

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So step into that function to see where & why it blocks ...

[Azizz]

void delay_us(uint16_t time) {
 __HAL_TIM_SET_COUNTER(&htim6, 0);
 while (__HAL_TIM_GET_COUNTER(&htim6) < time);
}

Here is the delay_us function that i implemented. You can find the whole dht11.c in the zip file i sent earlier.
Who can i add a delay of 170us ?

[mƎALLEm]

---

@Azizz wrote:

void delay_us(uint16_t time) {
 __HAL_TIM_SET_COUNTER(&htim6, 0);
 while (__HAL_TIM_GET_COUNTER(&htim6) < time);
}

Here is the delay_us function that i implemented. You can find the whole dht11.c in the zip file i sent earlier.
Who can i add a delay of 170us ?

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So I think all your code is based on the polling which is not a good idea. As I said rewrite your code and use interrupts instead of polling.

[Azizz]

So i should use another timer instead of TIM6 so i can use it as input capture or PWM input ?

[mƎALLEm]

That's not a CAN related subject it's related to how your code is organized and how you selected the NVIC priorities for the system tick, timer, and CAN.

Need to rewrite DHT11_Check_Response() with interrupt instead of polling on a GPIO pin status. I don't know how the DHT11 sensor is working but think to use a timer as input capture or PWM input to read the sensor instead of that blocking code.

[Azizz]

So i tried adding the interrupt function by adding this portion of code 

void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim) {
	if (htim->Instance == TIM3){
		 // Lire la valeur capturée
		 capture_time2 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_1);

		 // Si capture_time2 est plus grand que capture_time1, cela signifie que c'est une transition de montée
		 if (capture_time2 > capture_time1) {

		 	 // Calculer la durée de la pulse entre capture_time1 et capture_time2
		 uint32_t pulse_width = capture_time2 - capture_time1;

		 // Déterminer si le pulse correspond à un bit 0 ou 1 en fonction de sa durée
		 if (pulse_width > 50 && pulse_width < 100) { // Environ 26-28 µs pour bit bas
		 // Bit 0
		 data_buffer[bit_count / 8] &= ~(1 << (7 - (bit_count % 8))); // Mettre à 0 le bit correspondant
		 }

		 else if (pulse_width > 100 && pulse_width < 150) { // Environ 70 µs pour bit haut
		 // Bit 1
		 data_buffer[bit_count / 8] |= (1 << (7 - (bit_count % 8))); // Mettre à 1 le bit correspondant
		 }

		 bit_count++;

		 if (bit_count >= DHT11_MAX_BITS) {
		 // Lecture terminée
		 // Traiter les données (par exemple, les afficher ou les transmettre à une autre partie du programme)
		 Process_DHT11_Data();
		 }
		 }

		 // Mettre à jour capture_time1 pour la prochaine capture
		 capture_time1 = capture_time2;
 }
}

The problem is i never get the data from the DHT11 sensor because the program never enters this code and always repeats the function void HAL_TIM_PeriodElapsedCallback (TIM_HandleTypeDef *htim)