STM32F407 TIM8 complementary

Question

I can't figure out why my code doesn't work! I've worked with TIM1 and everything works fine but when I change to TIM8, PC6 and PC7 are always on and the complementaries always off. Please help me out and happy holidays!

/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_tim.h"
#include "misc.h"

/* Private typedef -----------------------------------------------------------*/
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
TIM_BDTRInitTypeDef TIM_BDTRInitStructure;

/* Private define ------------------------------------------------------------*/
#define frequency 42500 /* output frequency 42500 KHz */
#define f1 1/2 /* phase shift 90 degrees */

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
int TimerPeriod = 0;

/* Private function prototypes -----------------------------------------------*/
void TIM_Config(void);

/* Private functions ---------------------------------------------------------*/

/**
  * Main program
  */
int main(void)
{

  /* TIM8 Configuration */
  TIM_Config();

  /* Compute the value to be set in ARR register to generate the desired signal frequency */
  TimerPeriod = ((SystemCoreClock/2) / frequency) - 1;

  /* Time Base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseStructure.TIM_Period = TimerPeriod;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;

  TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);

  /* Channel 1 and 2 Configuration in Toggle mode */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;

  TIM_OCInitStructure.TIM_Pulse = (TimerPeriod/6)+ (TimerPeriod * f1);
  TIM_OC1Init(TIM8, &TIM_OCInitStructure);

  TIM_OCInitStructure.TIM_Pulse = (TimerPeriod/6) ;
  TIM_OC2Init(TIM8, &TIM_OCInitStructure);

  /* Automatic Output enable, Break, dead time and lock configuration*/
  TIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable;
  TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable;
  TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_1;
  TIM_BDTRInitStructure.TIM_DeadTime = 25; ///////// the right value for 250ns delay ////////
  TIM_BDTRInitStructure.TIM_Break = TIM_Break_Enable;
  TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_High;
  TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable;

  TIM_BDTRConfig(TIM8, &TIM_BDTRInitStructure);

  /* TIM8 counter enable */
  TIM_Cmd(TIM8, ENABLE);

  /* Main Output Enable */
  TIM_CtrlPWMOutputs(TIM8, ENABLE);

  while (1)
  {
  }
}

/**
  *  Configure the TIM8 Pins.
  */
void TIM_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* GPIOA, GPIOB and GPIOC clocks enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC, ENABLE);

  /* TIM8 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  /*GPIOA Configuration: Channel 1N and BKIN as alternate function push-pull*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* GPIOA Configuration: Channel 1 and 2 as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* GPIOB Configuration: Channel 2N as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* Connect TIM pins to AF1 */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_TIM8);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_TIM8);
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_TIM8);
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_TIM8);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource0, GPIO_AF_TIM8);

}

Which board are you using? If it's the F4 discovery then note that some of the TIM8 channel pins are taken by other peripherals on that board. Refer to the schematic and only choose pins labelled as "Free I/O". — Andy Brown
Well if I change my code for TIM1 it's true that every pin is "Free I/O". Well I think the most important pin is the BKIN. But if you search for TIM8_BKIN there is only one, PA6, which isn't "Free I/O". — co2ark5
@co2ark5 Hi... Have you solved this problem? I am also facing same! — Swanand

co2ark5 co2ark5 · Accepted Answer · 2016-06-28T09:09:29

@Swanand try to change this

TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Set;

and let me know.

STM32F407 TIM8 complementary

1 Answers