Timer output influenced by other timer

[Tomas Hamouz]

Hi everybody,

I have TIM15, configured to PWM generation, in one shot configuration, using OC1N output. The output is set to 0 and timer disabled.. 

When I later initialize TIM1, the output of TIM15 goes high at the instant the Update event is generated. I noticed it depend on Fast mode setting - if not set, the output remains low. The Fast mode is required/recommended in One Pulse configuration.

How is it possible to change anything in other timer instance?

Sample code below.

Tomas

//-----------------------------------------------------------------------------
void TIM15_TIM1_Test(void)
//-----------------------------------------------------------------------------
{
    // TIM15 init
    LL_TIM_InitTypeDef      TIM_InitStruct;
    TIM_InitStruct.Prescaler = 383; //
    TIM_InitStruct.CounterMode = LL_TIM_COUNTERMODE_UP;
    TIM_InitStruct.Autoreload = 100;
    TIM_InitStruct.ClockDivision = LL_TIM_CLOCKDIVISION_DIV1;
    TIM_InitStruct.RepetitionCounter = 0;
    LL_TIM_Init(TIM15, &TIM_InitStruct);

    // output channel setup
    LL_TIM_OC_InitTypeDef   TIM_OC_InitStruct;
    TIM_OC_InitStruct.OCMode = LL_TIM_OCMODE_PWM1;
    TIM_OC_InitStruct.OCState = LL_TIM_OCSTATE_DISABLE;
    TIM_OC_InitStruct.OCNState = LL_TIM_OCSTATE_ENABLE;
    TIM_OC_InitStruct.CompareValue = 50;
    TIM_OC_InitStruct.OCPolarity = LL_TIM_OCPOLARITY_LOW;
    TIM_OC_InitStruct.OCNPolarity = LL_TIM_OCPOLARITY_LOW;
    TIM_OC_InitStruct.OCIdleState = LL_TIM_OCIDLESTATE_LOW;
    TIM_OC_InitStruct.OCNIdleState = LL_TIM_OCIDLESTATE_LOW;
    LL_TIM_OC_Init(TIM15, LL_TIM_CHANNEL_CH1, &TIM_OC_InitStruct);

    LL_TIM_SetOffStates(TIM15, LL_TIM_OSSI_ENABLE, LL_TIM_OSSR_ENABLE);
    // here sits the devil - if I omit the Fast mode, it works fine
    LL_TIM_OC_EnableFast(TIM15, LL_TIM_CHANNEL_CH1);
    LL_TIM_EnableAllOutputs(TIM15);

    LL_TIM_GenerateEvent_UPDATE(TIM15);
    LL_TIM_EnableCounter(TIM15);    // needed to set the output to 0

    // connect pin to timer
    LL_GPIO_InitTypeDef GPIO_InitStruct;
    GPIO_InitStruct.Pin = BEEPER_PIN;
    GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
    GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
    GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
    GPIO_InitStruct.Alternate = BEEPER_AF;
    LL_GPIO_Init(BEEPER_PORT, &GPIO_InitStruct);

    LL_TIM_DisableCounter(TIM15);             // to be started later

    // TIM1 init
    LL_TIM_InitTypeDef TIM_InitStruct;
    TIM_InitStruct.Prescaler = 0;
    TIM_InitStruct.CounterMode = LL_TIM_COUNTERMODE_UP;
    TIM_InitStruct.Autoreload = 959;
    TIM_InitStruct.ClockDivision = LL_TIM_CLOCKDIVISION_DIV1;
    TIM_InitStruct.RepetitionCounter = 0;
    // in this call the output TIM15/OC1N goes high
    // at the instant of UpdateEvent generation   
    LL_TIM_Init(TIM1, &TIM_InitStruct);
}

[KnarfB]

Line 6 and line 47 define the same variable, this cannot compile.

[waclawek.jan]

As @KnarfB pointed out above, there's no point in posting conflicting code fragments. Always copy/paste coherent portions of code. Best, prepare a minimal but complete compilable example exhibiting the problem.

Which pins? Is there a change on TIM1-related pin at the "critical moment"? Check there's no physical short between them.

Read out and check/post content of TIM and relevant GPIO registers just before the "critical moment".

JW

PS.

> The Fast mode is required/recommended in One Pulse configuration.

Do you understand, why?

[Tomas Hamouz]

I am sorry, I merged two init functions from two modules into one example code. Since the init structure is fully initilized, it is sufficient to delete the second definition and there is no common data between the two initializations.

Tomas

[Tomas Hamouz]

>Always copy/paste coherent portions of code. Best, prepare a minimal but complete compilable example exhibiting the problem.

I did that, but after isolating the problematic code I merged two functions into one, as I have answered to @KnarfB.

So I have posted only one function instead of three (InitTIM15 + InitTIM1 + Call the two above). I hope I will not be crucified for that.

>Which pins? Is there a change on TIM1-related pin at the "critical moment"? Check there's no physical short between them.

TIM1 has no external connection, it is used for ADC timing. I know, there are better timers suitable for this task, but I needed two timers, capable to run i master/slave configuration and connectable to pins, which are not occupied by other non-relocatable devices. And several other requirements. The final choice is TIM1 and TIM3.

TIM15 has separate functionality and has no connection with the two timers above, either internal or external.

>> The Fast mode is required/recommended in One Pulse configuration.

>Do you understand, why?

If I understand RM correctly, it is necessary to minimize delay between start stimulus and generated pulse.

Tomas

[waclawek.jan]

Read out and check/post content of TIM and relevant GPIO registers just before the "critical moment".

You single-step in the through that critical moment (TIM1 Update), don't you. You may also want to compare the registers' content before and after that step.

JW