STM32F429i - Discovery PWM

[zereflai]

Posted on April 30, 2014 at 19:55

I was wondering what is the problem with the code that I have copied and changed the pin configuration. The objective of the code is to have a PWM output on the LEDS of the STM32F429 Discovery Board. The LEDs are assigned in PG.13 and PG.14. Credits to 

sourcer32 for the code he shared in the forum.

By the way the board has a 168MHz Clock/* Includes ------------------------------------------------------------------*/&sharpinclude ''stm32f4xx.h''// STM32 PWM 8 MHz (TIM1 CH1 PG.13, CH1N PG.14) STM32F4 Discovery - sourcer32@gmail.com      /**************************************************************************************/   void RCC_Configuration(void){  /* --------------------------- System Clocks Configuration -----------------*/  /* TIM1 clock enable */  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);     /* GPIOG clock enable */  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOG, ENABLE);}   /**************************************************************************************/   void GPIO_Configuration(void){  GPIO_InitTypeDef GPIO_InitStructure;     /*-------------------------- GPIO Configuration ----------------------------*/  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;  GPIO_Init(GPIOG, &GPIO_InitStructure);     /* Connect TIM1 pins to AF */  GPIO_PinAFConfig(GPIOG, GPIO_PinSource13, GPIO_AF_TIM1); // PG.13 TIM1_CH1  GPIO_PinAFConfig(GPIOG, GPIO_PinSource14, GPIO_AF_TIM1); // PG.14 TIM1_CH1N}   /**************************************************************************************/   void TIM1_Configuration(void){  TIM_OCInitTypeDef  TIM_OCInitStructure;  TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;  uint16_t Period;     Period = (SystemCoreClock / 8000000);     /* Time base configuration */  TIM_TimeBaseStructure.TIM_Prescaler = 0; // Dump 1X clock into timer  TIM_TimeBaseStructure.TIM_Period = Period - 1;  TIM_TimeBaseStructure.TIM_ClockDivision = 0;  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);     /* TIM PWM1 Mode configuration */  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;  TIM_OCInitStructure.TIM_Pulse = Period / 2; // 50%   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;   TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;     /* Output Compare PWM1 Mode configuration: Channel1 PG.13/PA.14 */  TIM_OC1Init(TIM1, &TIM_OCInitStructure);     /* TIM1 Main Output Enable */  TIM_CtrlPWMOutputs(TIM1, ENABLE);     /* TIM1 enable counter */  TIM_Cmd(TIM1, ENABLE);}   /**************************************************************************************/   int main(void){  RCC_Configuration();     GPIO_Configuration();   TIM1_Configuration();   while(1); // Don't want to exit} /**************************************************************************************/ &sharpifdef  USE_FULL_ASSERT /**  * @brief  Reports the name of the source file and the source line number  *   where the assert_param error has occurred.  * @param  file: pointer to the source file name  * @param  line: assert_param error line source number  * @retval None  */void assert_failed(uint8_t* file, uint32_t line){  /* User can add his own implementation to report the file name and line number,     ex: printf(''Wrong parameters value: file %s on line %d\r\n'', file, line) */   /* Infinite loop */  while (1)  {  }}&sharpendif /**  * @}  */ /**************************************************************************************/ #pwm #stm32f429discovery

[Tesla DeLorean]

Posted on April 30, 2014 at 20:10

I was wondering what is the problem with the code that I have copied and changed the pin configuration. The objective of the code is to have a PWM output on the LEDS of the STM32F429 Discovery Board. The LEDs are assigned in PG.13 and PG.14. Credits to sourcer32 for the code he shared in the forum.

Neither of these pins have any associativity with TIM1, and you can't make up random associations to suit. You'll need to review the data sheet

http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00071990.pdf

You'd be better picking some pins that connect to timers, and that you can attach to a scope. LEDs at 8 MHz not being perceivable to the human eye.

[zereflai]

Posted on May 02, 2014 at 04:53

Got the datasheet for the STM32F429 and got to see the Alternative Function of the different pins. Thanks for the enlightenment ^_^

Thanks,Ian Alferez