STM32 Timer One Pulse Mode

Timer one pulse mode
One pulse mode (OPM) is a particular case of the input capture mode and the output
compare mode. It allows the counter to be started in response to a stimulus and to generate
a pulse with a programmable length after a programmable delay.
To configure the timer this mode:
1. Configure the input pin and mode:
a) Select the TIxFPx trigger to be used by writing CCxS bits in CCMRx register.
b) Select the polarity of the input pin by writing CCxP and CCxNP bits in CCER
register.
c) Configure the TIxFPx trigger for the slave mode trigger by writing TS bits in SMCR
register.
d) Select the trigger mode for the slave mode by writing SMS = 110 in SMCR
register.
2. Configure the output pin and mode:
a) Select the output polarity by writing CCyP bit in CCER register.
b) Select the output compare mode by writing OCyM bits in CCMRy register (PWM1
or PWM2 mode).
c) Set the delay value by writing in CCRy register.
d) Set the auto reload value to have the desired pulse: pulse = TIMy_ARR -
TIMy_CCRy.
3. Select the one pulse mode by setting the OPM bit in CR1 register, if only one pulse is to
be generated. Otherwise this bit should be reset.
Delay = CCRy/(TIMx_CLK/(PSC + 1))
Pulse-Length = (ARR - CCRy)/(TIMx_CLK/(PSC + 1))
For more details on using the timer in this mode, refer to the examples provided in the
STM32xx standard peripheral libraries, in the /Project/STM32xx_StdPeriph_Examples/
TIM/OnePulse folder

void Init_TIM15(void)
{
RCC->APB2ENR |= RCC_APB2ENR_TIM15EN;   // TIM15 clock enable (Master)
TIM15->PSC  = PERIOD - 1;   
TIM15->ARR  = LCD_BUFFER_SIZE + PULSE - 1;   
TIM15->CCR1 = PULSE;             // Pulse_Output = ARR - CCR1
TIM15->CCMR1 |= (TIM_CCMR1_OC1M_0 | TIM_CCMR1_OC1M_1 | TIM_CCMR1_OC1M_2 | TIM_CCMR1_OC1FE); // PWM Mode2   
TIM15->CR1   |= TIM_CR1_OPM;     // Select One-pulse mode 
TIM15->CR2   |= TIM_CR2_MMS_2;   // MMS=100 Compare - OC1REF signal is used as trigger output (TRGO)
TIM15->EGR   |= TIM_EGR_UG;      // Update Generation

}

периодическая генерация

TIM1->CR1 = 0;
TIM1->CR2 = (4 << TIM_CR2_MMS); // OC1REF -> TRGO
TIM1->PSC = 72 - 1;
TIM1->ARR = 500 - 1;
TIM1->EGR = (1 << TIM_EGR_UG);
TIM1->CCMR1 = (OC_MODE_PWM2 << TIM_CCMR1_OC1M);
TIM1->CCER = (1 << TIM_CCER_CC1E);
TIM1->BDTR = (1 << TIM_BDTR_MOE);
TIM1->CCR1 = 100;

TIM3->CR1 = 0;
TIM3->PSC = 72 - 1;
TIM3->ARR = 0xffff;
TIM3->EGR = (1 << TIM_EGR_UG);
TIM3->CCMR1 = (OC_MODE_PWM1 << TIM_CCMR1_OC1M) | (OC_MODE_PWM1 << TIM_CCMR1_OC2M);
TIM3->CCER = (1 << TIM_CCER_CC1E) | (1 << TIM_CCER_CC2E);
TIM3->SMCR =
(0 << TIM_SMCR_TS) // TRGI -> ITR0 (TIM1)
| (4 << TIM_SMCR_SMS); // Reset Mode

TIM3->CCR1 = 40;
TIM3->CCR2 = 5;
TIM3->CR1 = (1 << TIM_CR1_CEN);

TIM1->CR1 = (1 << TIM_CR1_CEN);




однократная генерация

TIM1->CR1 = 0;
TIM1->CR2 = (4 << TIM_CR2_MMS); // OC1REF -> TRGO
TIM1->PSC = 72 - 1;
TIM1->ARR = 500 - 1;
TIM1->EGR = (1 << TIM_EGR_UG);
TIM1->CCMR1 = (OC_MODE_PWM2 << TIM_CCMR1_OC1M);
TIM1->CCER = (1 << TIM_CCER_CC1E);
TIM1->BDTR = (1 << TIM_BDTR_MOE);
TIM1->CCR1 = 100 - 1; // на один такт меньше

TIM3->CR1 = 0;
TIM3->PSC = 72 - 1;
TIM3->ARR = 0xffff;
TIM3->EGR = (1 << TIM_EGR_UG);
TIM3->CCMR1 = (OC_MODE_PWM1 << TIM_CCMR1_OC1M) | (OC_MODE_PWM1 << TIM_CCMR1_OC2M);
TIM3->CCER = (1 << TIM_CCER_CC1E) | (1 << TIM_CCER_CC2E);
TIM3->SMCR =
(0 << TIM_SMCR_TS) // TRGI -> ITR0 (TIM1)
| (5 << TIM_SMCR_SMS); // Gated Mode

TIM3->CCR1 = 40;
TIM3->CCR2 = 5;
TIM3->CR1 = (1 << TIM_CR1_CEN);

while(1)
{
if(pulse)
{
TIM3->CNT = 0xffff; // -1 для генерации события UR
TIM1->CR1 = (1 << TIM_CR1_CEN) | (1 << TIM_CR1_OPM);
pulse = 0;
}
}



TIM15 to generate a delay, programmable width pulse, triggered by an external input.  For the external input, I am using TIM3 routed to the appropriate pin (PA3) which is TIM15_CH2


static void TIM_Config(void)
{
  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
  TIM_ICInitTypeDef  TIM_ICInitStructure;
  TIM_OCInitTypeDef  TIM_OCInitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;

  /* TIM15 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM15, ENABLE);

  /* GPIOA clock enable */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
   
  /* TIM15_CH1 pin (PA.02) and TIM15_CH2 pin (PA.03) configuration */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Connect TIM pins to AF0 */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_0);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_0);

  /* --------------------------------------------------------------------------
    TIM15 configuration: One Pulse mode
    The external signal is connected to TIM15_CH2 pin (PA03),
    The Rising edge is used as active edge,
    The One Pulse signal is output on TIM15_CH1 pin (PA02)
    The TIM_Pulse defines the delay value
    The (TIM_Period -  TIM_Pulse) defines the One Pulse value.
  --------------------------------------------------------------------------- */

  /* Compute the prescaler value */
  PrescalerValue = (uint16_t) ((SystemCoreClock ) / 24000000) - 1;
   
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 65535;
  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM15, &TIM_TimeBaseStructure);

  /* TIM15 PWM2 Mode configuration: Channel1 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = 16383;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OC1Init(TIM15, &TIM_OCInitStructure);

  /* TIM configuration in Input Capture Mode */
  TIM_ICStructInit(&TIM_ICInitStructure);
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
  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(TIM15, &TIM_ICInitStructure);

  /* One Pulse Mode selection */
  TIM_SelectOnePulseMode(TIM15, TIM_OPMode_Single);

  /* Input Trigger selection */
  TIM_SelectInputTrigger(TIM15, TIM_TS_TI2FP2);

TIM15->BDTR |= TIM_BDTR_MOE; ///!!!!!!!!!!!!!!!!!!

  /* Slave Mode selection: Trigger Mode */
  TIM_SelectSlaveMode(TIM15, TIM_SlaveMode_Trigger);
  TIM_Cmd(TIM15, ENABLE);

}