Programación de Embedded Lanqiao Cup PWM

En primer lugar, confirmamos si el pin de salida PWM es

PA6 TIM3 CH1 como salida 1
PA7 TIM3 CH2 como salida 2
o abrimos el archivo de la biblioteca de firmware 32 sobre la salida PWM. La
ruta es la siguiente
\ Biblioteca de firmware STM32 v3.5 \ STM32F10x_StdPeriph_Lib_V3.5.0 \ Project \ STM32F10x_StdPeriph_Examples \
Encuentra la función principal de TIM \ PWM_Output y copia todo el contenido a la función
void TIM3_PWM_Init (void) que creamos

void TIM3_PWM_Init（void）{
    
    }

Debido a que la cantidad de código es demasiado grande para afectar la lectura, no lo publicaré

Luego copiamos el nombre del destructor

TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

Luego escribimos el valor de pantalla pre-dividida

uint16_t PrescalerValue = 0;

Entonces se escribe el valor de CCR1

uint16_t CCR1_Val = 333;

Luego borramos las funciones configuradas
por el CCR restante. Las funciones del CCR restante son las siguientes

  /* PWM1 Mode configuration: Channel2 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
  TIM_OC2Init(TIM3, &TIM_OCInitStructure);
  TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
  /* PWM1 Mode configuration: Channel3 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
  TIM_OC3Init(TIM3, &TIM_OCInitStructure);
  TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
  /* PWM1 Mode configuration: Channel4 */
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
    TIM_OC4Init(TIM3, &TIM_OCInitStructure);
  TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);

Luego configure las dos funciones que reportamos.
De hecho, la librería de firmware usa referencias de función.
Solo necesitamos reemplazar los nombres de los módulos de función correspondientes.

El primero es el archivo RCC

void RCC_Configuration(void)
{
    
    
  /* TIM3 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  /* GPIOA and GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |
                         RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
}

La salida PWM que utilizamos es
TIM3 CCR2 correspondiente al pin
PA7 TIM2 CCR2 correspondiente al pin PA1

Así que solo mantenemos los puertos TIM3 y PA y el reloj multiplexado

  /* TIM3 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  /* GPIOA and GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

El siguiente es nuestro puerto GPIO pin IO.
Igual que en el proceso de configuración anterior,
busque este código

  /*GPIOB Configuration: TIM3 channel1, 2, 3 and 4 */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
  GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);	

Entonces solo mantén PA7

  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

A continuación, configuramos la entrada y salida de un puerto IO.
A continuación, calculemos la frecuencia PWM de salida.
Echemos un vistazo a este comentario.

  /* -----------------------------------------------------------------------
    TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
    The TIM3CLK frequency is set to SystemCoreClock (Hz), to get TIM3 counter
    clock at 24 MHz the Prescaler is computed as following:
     - Prescaler = (TIM3CLK / TIM3 counter clock) - 1
    SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density
    and Connectivity line devices and to 24 MHz for Low-Density Value line and
    Medium-Density Value line devices

    The TIM3 is running at 36 KHz: TIM3 Frequency = TIM3 counter clock/(ARR + 1)
                                                  = 24 MHz / 666 = 36 KHz
    TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
    TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
    TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
    TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
  ----------------------------------------------------------------------- */

Dice que ha descompuesto 72Mhz en 24Mhz,
supongo que es esta frase

  PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;

El valor de preasignación es igual al reloj dividido por 24000000-1
y luego el reloj se divide por el valor del preescalador
. La ventaja de escribir de esta manera es que no importa cuánto se divida la frecuencia de su reloj por este PrescalerValue,
obtendrá 24Mhz

Luego vi que 24Mhz se dividió en 36KHz,
supongo que fue esta oración

  TIM_TimeBaseStructure.TIM_Period = 665;

Establezca el ciclo en 665 para completar un ciclo y la frecuencia se convierte en 36 KHz
. Si queremos obtener 40 KHz ,
debemos calcularlo a la inversa. 240 000 K / 40 K = 600,
así que cambiamos

  TIM_TimeBaseStructure.TIM_Period = 599;

Por lo tanto, debería ser posible lograr una salida de onda cuadrada de 40 KHz para uso ultrasónico. El
siguiente es el código completo de la configuración PWM

#include "timer.h"
_Bool TIM2_led_flag =0; 
u8 Tim2_conter =0;

void TIM2_Config(void)
{
    
    
  TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStrure;
  NVIC_InitTypeDef NVIC_InitStrure;
	RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
	
	TIM_TimeBaseInitStrure.TIM_CounterMode=TIM_CounterMode_Up;
	TIM_TimeBaseInitStrure.TIM_Period=1000;//¼ÆÊýµ½1000 µÈÓÚ³ËÒÔÁË1000
	TIM_TimeBaseInitStrure.TIM_Prescaler=  71 ; //72HMz/72=1Mhz = 1 000 000
	TIM_TimeBaseInitStrure.TIM_RepetitionCounter= 0;                //Öظ´ÇëÇó¼ÆÊýÆ÷
	TIM_TimeBaseInit(TIM2,&TIM_TimeBaseInitStrure);
	
  TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);
	TIM_Cmd(TIM2,ENABLE);
	
	
	NVIC_InitStrure.NVIC_IRQChannel=TIM2_IRQn;
	NVIC_InitStrure.NVIC_IRQChannelCmd=ENABLE;
	NVIC_InitStrure.NVIC_IRQChannelPreemptionPriority=0;
	NVIC_InitStrure.NVIC_IRQChannelSubPriority=1;
	NVIC_Init(&NVIC_InitStrure);
	
}
void TIM2_IRQHandler()
{
    
    
	if(TIM_GetITStatus(TIM2,TIM_IT_Update)!=RESET)
	{
    
    
		Tim2_conter++;
		
		TIM_ClearITPendingBit(TIM2,TIM_IT_Update);
		if(Tim2_conter > 250)
		{
    
    
		Tim2_conter=0;
		TIM2_led_flag = !TIM2_led_flag;
		}
	}
}

void TIM3_PWM_Init(void)
{
    
    
 uint16_t PrescalerValue = 0;
 uint16_t CCR1_Val = 333;
 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
 TIM_OCInitTypeDef  TIM_OCInitStructure;
 GPIO_InitTypeDef GPIO_InitStructure;   
  /* System Clocks Configuration */
  /* TIM3 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

  /* GPIOA and GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

  /* GPIO Configuration */
    /*GPIOB Configuration: TIM3 channel1, 2, 3 and 4 */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);	


  /* -----------------------------------------------------------------------
    TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
    The TIM3CLK frequency is set to SystemCoreClock (Hz), to get TIM3 counter
    clock at 24 MHz the Prescaler is computed as following:
     - Prescaler = (TIM3CLK / TIM3 counter clock) - 1
    SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density
    and Connectivity line devices and to 24 MHz for Low-Density Value line and
    Medium-Density Value line devices

    The TIM3 is running at 36 KHz: TIM3 Frequency = TIM3 counter clock/(ARR + 1)
                                                  = 24 MHz / 666 = 36 KHz
    TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
    TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
    TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
    TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
  ----------------------------------------------------------------------- */
  /* Compute the prescaler value */
  PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 599;
  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* PWM1 Mode configuration: Channel1 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC2Init(TIM3, &TIM_OCInitStructure);

  TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);

  TIM_ARRPreloadConfig(TIM3, ENABLE);

  /* TIM3 enable counter */
  TIM_Cmd(TIM3, ENABLE);

}




void TIM2_PWM_Init(void)
{
    
    
 uint16_t PrescalerValue = 0;
 uint16_t CCR1_Val = 300;
 TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
 TIM_OCInitTypeDef  TIM_OCInitStructure;
 GPIO_InitTypeDef GPIO_InitStructure;   
  /* System Clocks Configuration */
  /* TIM2 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  /* GPIOA and GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

  /* GPIO Configuration */
    /*GPIOB Configuration: TIM2 channel1, 2, 3 and 4 */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_1;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_PinRemapConfig(GPIO_FullRemap_TIM2, ENABLE);	


  /* -----------------------------------------------------------------------
    TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
    The TIM3CLK frequency is set to SystemCoreClock (Hz), to get TIM3 counter
    clock at 24 MHz the Prescaler is computed as following:
     - Prescaler = (TIM3CLK / TIM3 counter clock) - 1
    SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density
    and Connectivity line devices and to 24 MHz for Low-Density Value line and
    Medium-Density Value line devices

    The TIM3 is running at 36 KHz: TIM3 Frequency = TIM3 counter clock/(ARR + 1)
                                                  = 24 MHz / 666 = 36 KHz
    TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
    TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
    TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
    TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
  ----------------------------------------------------------------------- */
  /* Compute the prescaler value */
  PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
  /* Time base configuration */
  TIM_TimeBaseStructure.TIM_Period = 599;
  TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* PWM1 Mode configuration: Channel1 */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_Pulse = CCR1_Val;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

  TIM_OC2Init(TIM2, &TIM_OCInitStructure);

  TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable);

  TIM_ARRPreloadConfig(TIM2, ENABLE);

  /* TIM3 enable counter */
  TIM_Cmd(TIM2, ENABLE);

}