TIM4 in Encoder Mode - Nucleo F767ZI

Posted on October 06, 2016 at 22:09

This is the TIM4 Init code as generated by Cube:

/* TIM4 init function */
static void MX_TIM4_Init(void)
{
TIM_Encoder_InitTypeDef sConfig;
TIM_MasterConfigTypeDef sMasterConfig;
htim4.Instance = TIM4;
htim4.Init.Prescaler = 0;
htim4.Init.CounterMode = TIM_COUNTERMODE_UP;
htim4.Init.Period = 0xffff;
htim4.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
sConfig.EncoderMode = TIM_ENCODERMODE_TI12;
sConfig.IC1Polarity = TIM_ICPOLARITY_BOTHEDGE;
sConfig.IC1Selection = TIM_ICSELECTION_DIRECTTI;
sConfig.IC1Prescaler = TIM_ICPSC_DIV1;
sConfig.IC1Filter = 0;
sConfig.IC2Polarity = TIM_ICPOLARITY_BOTHEDGE;
sConfig.IC2Selection = TIM_ICSELECTION_DIRECTTI;
sConfig.IC2Prescaler = TIM_ICPSC_DIV1;
sConfig.IC2Filter = 0;
if (HAL_TIM_Encoder_Init(&htim4, &sConfig) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim4, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
}

And I'm using

HAL_TIM_IC_CaptureCallback

to get the interrupts and calculate externally. At the same time I am comparing it to the TIM4->CNT value which doesn't seem to count up or down consistently.

Posted on October 07, 2016 at 07:45

I was working on something just like this just last night, but for a 407. 

Try watching this:

https://www.youtube.com/watch?v=GoRYhhdVR3M

Ignore what he is saying, unless you understand Russian, but he shows all of the steps to do encoders using Cube.

Andrei from The Great White North

Posted on October 07, 2016 at 10:28

HiNeo,

I think you missed to add the start of Timer Encoder interface by adding the following (as example):

/* Start the encoder interface */
HAL_TIM_Encoder_Start(&Encoder_Handle, TIM_CHANNEL_ALL);

Unfortunaly, the STM32CubeF7 does not contains an encoder example. You would take a look to another STM32Cube package like

http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software/stm32cubef4.html

which has the example ''TIM_Encoder''at this path: STM32Cube_FW_F4_V1.0\Projects\STM324xG_EVAL\Examples\TIM\TIM_Encoder I will submit a request to add such example in the STM32CubeF7 package. -Hannibal-

Posted on October 07, 2016 at 14:20

Hannibal,

I am starting the encoder using HAL_TIM_Encoder_Start(). I just posted the Timer initialization part that the Cube generated. 

The TIM4->CNT value changes, but it keeps going up and down, and so does the DIR bit. I am not sure why it is doing that, when the motor is consistently running in only one direction.

Thanks.

Posted on October 07, 2016 at 15:54

Hi Neo, 

So try to play on ICpolarity, put one edge (up or down).

-Hannibal-

Posted on October 07, 2016 at 16:44

Thanks Hannibal!

It seems to be counting properly now.

But I am wondering why is it so? Why can't it count properly when the ICPolarity is set to Both Edges?

Posted on October 07, 2016 at 17:43

Hi Neo, 

The both Edge Sensitive case is dedicated for another different encoding type .

-Hannibal-