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stm32f0 discovery board to run One Pulse Mode on timer 2

ming2
Associate III
Posted on July 09, 2015 at 22:13

Hi, I am using the discovery board to try OPM on timer 2. I can not get it going with any effort on my code list below. Please help!!! It is important to our new product.

void GPIO_Configuration(void);

int main(void)

{

  /* System Clocks Configuration */

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA|RCC_AHBPeriph_GPIOC, ENABLE);

    RCC_APB1PeriphResetCmd(RCC_APB1Periph_TIM2, ENABLE);

  /* Configure the GPIO ports */

  GPIO_Configuration();

  /* TIM2 configuration: One Pulse mode ------------------------

     The external signal is connected to TIM2_CH2 pin (PA.01),

     The Rising edge is used as active edge,

     The One Pulse signal is output on TIM2_CH1 pin (PA.00)

     The TIM_Pulse defines the delay value

     The (TIM_Period -  TIM_Pulse) defines the One Pulse value.

     The TIM2CLK is fixed to 72 MHz, the Prescaler is 1, so the

     TIM2 counter clock is 36 MHz.

     The Autoreload value is 65535 (TIM2->ARR), so the maximum

     frequency value to trigger the TIM2 input is 500 Hz.

     The TIM_Pulse defines the delay value, the delay value is fixed

     to 455.08 us:

     delay =  CCR1/TIM2 counter clock = 455.08 us.

     The (TIM_Period - TIM_Pulse) defines the One Pulse value,

     the pulse value is fixed to 1.365ms:

     One Pulse value = (TIM_Period - TIM_Pulse)/TIM2 counter clock = 1.365 ms.

  ------------------------------------------------------------ */

  /* Time base configuration */

  TIM_TimeBaseStructure.TIM_Period = 65535;

  TIM_TimeBaseStructure.TIM_Prescaler = 1;

  TIM_TimeBaseStructure.TIM_ClockDivision = 0;

  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

  /* TIM2 PWM2 Mode configuration: Channel1 */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_Pulse = 16383;   //delay..

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;

  TIM_OC2Init(TIM2, &TIM_OCInitStructure);  //PA1 output.

  /* TIM2 PWM2 Mode configuration: Channel3 */

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;

  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

  TIM_OCInitStructure.TIM_Pulse = 1; //No delay, immediate reacts to input.

  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;

  TIM_OC3Init(TIM2, &TIM_OCInitStructure);   //PA2 output.

  /* TIM2 configuration in Input Capture Mode */

  TIM_ICStructInit(&TIM_ICInitStructure);

  TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; //PA0 trigger

  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;

  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;

  TIM_ICInitStructure.TIM_ICFilter = 0;

  TIM_ICInit(TIM2, &TIM_ICInitStructure);

  /* One Pulse Mode selection */

  TIM_SelectOnePulseMode(TIM2, TIM_OPMode_Single);

  /* Input Trigger selection */

  TIM_SelectInputTrigger(TIM2, TIM_TS_TI1FP1);

  /* Slave Mode selection: Trigger Mode */

  TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Trigger);

  //GPIO_SetBits(GPIOA,GPIO_Pin_1);

  while (1)

  {

 GPIO_SetBits(GPIOC,GPIO_Pin_8|GPIO_Pin_9); //Turn 2 leds on.

  }

}

///////////////////////////////////////////////////

void GPIO_Configuration(void)

{

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_1;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8|GPIO_Pin_9; //PC8,9 to be output pp.

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_2);

  GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_6);

  GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_6);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2; //PA2 to be alternative func.

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //PA0 to be alternative func.

    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

    GPIO_Init(GPIOA, &GPIO_InitStructure);

}

5 REPLIES 5
ming2
Associate III
Posted on July 09, 2015 at 22:25

P.S.   I am making 2 pulses out of ch2 and 3 by trigger from one source, ch1. Is it possible?

Posted on July 09, 2015 at 22:41

You want to enable the Clock, not Reset the peripheral

RCC_APB1PeriphResetCmd(RCC_APB1Periph_TIM2, ENABLE);

Really not sure if OPM is workable across multiple channels. I suspect if the Period setting was sufficient, PWM1/PWM2 modes on them might permit differing pulses.

Can you draw a timing diagram of the input vs output signals you're looking to generate?

Tips, buy me a coffee, or three.. PayPal Venmo Up vote any posts that you find helpful, it shows what's working..
ming2
Associate III
Posted on July 10, 2015 at 17:54

Thanks for the hint Clive1. It is now running but only with Repetitive mode. I can probe A1/A2 and get pulses repetitively as I want. But I need it to be triggered by my signal instead of auto run. 

Once I put it in Single mode, the 2 pins probed as all High no matter how I press the button on A0.... 

ming2
Associate III
Posted on July 10, 2015 at 18:00

Here is the code with Repetitive mode working:

  TIM_ICStructInit(&TIM_ICInitStructure);

  TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; //PA0 trigger with the button.

  TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;

  TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI; //connect CH1 to IC1.

  TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;

  TIM_ICInitStructure.TIM_ICFilter = 0;

  TIM_ICInit(TIM2, &TIM_ICInitStructure);

  /* One Pulse Mode selection */

  TIM_SelectOnePulseMode(TIM2, TIM_OPMode_Repetitive);

  /* Input Trigger selection */

  TIM_SelectInputTrigger(TIM2, TIM_TS_TI1FP1);

  /* Slave Mode selection: Trigger Mode */

  TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Trigger);

  TIM_Cmd(TIM2, ENABLE);

ming2
Associate III
Posted on July 10, 2015 at 20:05

It works now!! 2 pulses out of 1 trigger with programmable timing I want. 

I was doing wrong init to GPIOA which screwed up the AF scheme...