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zarkscon
zarkscon
Associate III
March 14, 2015
Question

stm32f407 TIM1 and TIM8 sync

  • March 14, 2015
  • 24 replies
  • 4048 views
Posted on March 14, 2015 at 15:18

Hello I'm trying to synchronize TIM1 and TIM8 (slaves) via TIM2 (master).. I checked the manual and says it can be done (p. 554/1710).. Although TIM2 works fine, TIM1 and TIM8 are off..

Please check my code bellow and help me out! 

/* Includes ------------------------------------------------------------------*/
#include ''stm32f4xx.h''
#include ''stm32f4xx_rcc.h''
#include ''stm32f4xx_gpio.h''
#include ''stm32f4xx_tim.h''
#include ''misc.h''
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_BDTRInitTypeDef TIM_BDTRInitStructure;
/* Private function prototypes -----------------------------------------------*/
void
TIM_Config(
void
);
/* Private functions ---------------------------------------------------------*/
int
main(
void
)
{
TIM_Config();
/* TIM1 Peripheral Configuration ----------------------------------------*/
/* TIM1 Slave Configuration: PWM1 Mode */
TIM_TimeBaseStructure.TIM_Period = 2;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 1;
TIM_OC1Init(TIM1, &TIM_OCInitStructure);
/* Slave Mode selection: TIM1 */
TIM_SelectSlaveMode(TIM1, TIM_SlaveMode_Gated);
TIM_SelectInputTrigger(TIM1, TIM_TS_ITR1);
/* TIM8 Peripheral Configuration ----------------------------------------*/
/* TIM8 Slave Configuration: PWM1 Mode */
TIM_TimeBaseStructure.TIM_Period = 2;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 1;
TIM_OC1Init(TIM8, &TIM_OCInitStructure);
/* Slave Mode selection: TIM8 */
TIM_SelectSlaveMode(TIM8, TIM_SlaveMode_Gated);
TIM_SelectInputTrigger(TIM8, TIM_TS_ITR1);
/* TIM2 Peripheral Configuration ----------------------------------------*/
/* Time Base configuration */
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 255;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 4;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
/* Channel 1 Configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
TIM_OCInitStructure.TIM_Pulse = 127;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
TIM_OC1Init(TIM2, &TIM_OCInitStructure);
/* Master Mode selection */
TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);
/* Select the Master Slave Mode */
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);
/* TIM2 counter enable */
TIM_Cmd(TIM2, ENABLE);
/* TIM enable counter */
TIM_Cmd(TIM1, ENABLE);
TIM_Cmd(TIM8, ENABLE);
/* Main Output Enable */
TIM_CtrlPWMOutputs(TIM2, ENABLE);
while
(1)
{}
}
void
TIM_Config(
void
)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOA and GPIOC clocks enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOC, ENABLE);
/* TIM1 and TIM8 clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_TIM8, ENABLE);
/* TIM2 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
/* GPIOA Configuration: TIM1 and TIM2 Channel1 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_0;
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;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* GPIOC Configuration: TIM8 Channel1 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* Connect TIM pins to AF1 */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_TIM1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM2);
/* Connect TIM pins to AF3 */
GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_TIM8);
}

Thanks in advance #discovery #stm32 #stm32f4
This topic has been closed for replies.

24 replies

Tesla DeLorean
Tesla DeLorean
Guru
March 14, 2015
Posted on March 14, 2015 at 16:56

TIM_CtrlPWMOutputs(TIM2, ENABLE);

Don't need that for TIM2, critical for TIM1 and TIM8 (they're special)

They also need the repetition count, set to zero.

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zarkscon
zarksconAuthor
Associate III
March 14, 2015
Posted on March 14, 2015 at 17:10

Thanks for the help but still nothing happens though TIM2 works fine..

Tesla DeLorean
Tesla DeLorean
Guru
March 14, 2015
Posted on March 14, 2015 at 18:25

Ok, I don't have my scope with me.

What board are you doing this on? And what signals do you expect to see (nature, frequency, etc)?

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zarkscon
zarksconAuthor
Associate III
March 14, 2015
Posted on March 14, 2015 at 23:52

I'm using stm32f407vgt6 discovery board and I want to start TIM1 and TIM8 simultaneously.. I used this as my template (

https://github.com/devthrash/STM32F4-workarea/tree/master/Project/STM32F4xx_StdPeriph_Examples/TIM/TIM_Synchro

)  which works fine but not when I change it for TIM1 and TIM8..

Tesla DeLorean
Tesla DeLorean
Guru
March 15, 2015
Posted on March 15, 2015 at 02:34

So you expect the timers to output a continuous frequency, what frequency, or modulate?

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zarkscon
zarksconAuthor
Associate III
March 15, 2015
Posted on March 15, 2015 at 12:08

I want TIM1 and TIM8 to work at 42.5KHz, which I haven't fix it inside the code, but I don't think it's an issue. TIM2 works at 105.3KHz right now, checked with my oscilloscope.. My HSE frequency is at 25MHz, usually I change it to 80MHz (system_stm32f4xx.c)..

Tesla DeLorean
Tesla DeLorean
Guru
March 16, 2015
Posted on March 16, 2015 at 01:59

Really not seeing Gated mode being at all appropriate for that. Surely a Reset mode driven by a one-shot would be the way to phase align two timers.

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Tesla DeLorean
Tesla DeLorean
Guru
March 16, 2015
Posted on March 16, 2015 at 02:02

42.5 KHz is not cleanly divisible into 80 MHz, perhaps you'd want to try 85 MHz?

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zarkscon
zarksconAuthor
Associate III
March 16, 2015
Posted on March 16, 2015 at 18:13

I can't see how reset mode would help me out, since it just resets the two clocks (I'll check it out though)..

The frequency of HSE doesn't mean a lot.. It's the timer period and prescaller which define the appropriate frequency.. For example on my code (not this one i posted here) I have SYSCLK=168MHz and HSE=80MHz.. Then I wrote that 

#define FREQUENCY 42500 /* output frequency 42500 KHz */
/* Compute the value to be set in ARR register to generate the desired signal frequency */
TimerPeriod = ((SystemCoreClock/2) / FREQUENCY) - 1;
TIM_TimeBaseStructure.TIM_Period = TimerPeriod - 1;
TIM_TimeBaseStructure.TIM_Prescaler = 0;

and the oscilloscope shows 5KHz..
Tesla DeLorean
Tesla DeLorean
Guru
March 16, 2015
Posted on March 16, 2015 at 18:48

I can't see how reset mode would help me out

Because you said your wanted to ''start'' the pair of timers together, presumably because they need to be phase aligned with each other. You only need to reset them once to have them phase aligned.

Gated would seem to suggest you are modulating the slave timers with a signal from the master timer.

HSE 80 MHz? HSE is the external clock, rated 1-50 MHz

Yes' I'm well aware that the prescaler/period of a timer relate to the output frequency as divided into the TIMCLK of the timer.
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