capturing frequency

[imanpakii]

Posted on February 13, 2013 at 18:40

Hi guys 

I'm working on a project, I need to fine filing edge of a stream with 4.000 Mhz  frequency.This is my code and IRQ sub program:  GPIO_InitTypeDef GPIO_InitStructure;  NVIC_InitTypeDef NVIC_InitStructure;  /* TIM1 clock enable */  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);  /* GPIOA clock enable */  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);  /* TIM1 channel 2 pin (PE.11) configuration */  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_11 ;  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(GPIOE, &GPIO_InitStructure);  /* Connect TIM pins to AF2 */  GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1);  /* Enable the TIM1 global Interrupt */  NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  NVIC_Init(&NVIC_InitStructure);  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; Delay(0x3FFFFF); TIM_ICInit(TIM1, &TIM_ICInitStructure); /* TIM enable counter */ TIM_Cmd(TIM1, DISABLE); //BLF=10144; //BLF=24806; /* Enable the CC2 Interrupt Request */TIM_Cmd(TIM1, ENABLE);TIM_ITConfig(TIM1, TIM_IT_CC2, ENABLE);TIM_ICInit(TIM1, &TIM_ICInitStructure);void TIM1_CC_IRQHandler(void){ Array1[index0] =TIM1->CCR2;     if(++index0>=60) index0=0; TIM_ClearITPendingBit(TIM1, TIM_IT_CC2);}but i couldn't measure 4 Mhz.please help me thank you   

[Tesla DeLorean]

Posted on February 13, 2013 at 19:13

Yeah, 4 MHz, not going to be able to interrupt and count clock tick deltas with that rate.

For high rates you want to slave a timer against the external clock, and integrate. Say over a period of 10us, sampling the counter, and observing 40000 ticks +/-

[imanpakii]

Posted on February 14, 2013 at 02:01Thank you Clive1i want to change my algorithm and i want to count my event with 4 mhz external clock.I configure timer 4 as external clock and i connect my pulse to this clock but it doesn't work .this is my code for configure timer4 and connect it to pb.6  GPIO_InitTypeDef GPIO_InitStructure;  NVIC_InitTypeDef NVIC_InitStructure;  /* GPIOA clock enable */  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);  /* TIM1 channel 2 pin (PE.11) configuration */  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_6 ;  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(GPIOE, &GPIO_InitStructure);  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_TIM4);  /* Connect TIM pins to AF2 */ GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1); TIM_ETRClockMode1Config(TIM4, TIM_ExtTRGPSC_OFF,TIM_ExtTRGPolarity_Inverted,0);TIM_Cmd(TIM4, ENABLE);  please help me as usual :)Thank you 

[Tesla DeLorean]

Posted on February 14, 2013 at 02:11

 GPIO_Init(GPIOE, &GPIO_InitStructure); // GPIO E ??

[imanpakii]

Posted on February 14, 2013 at 20:45

Hi Clive1 

thank you for your reply 

i changed that cod to portb but steel i have problem maybe i couldn't program my pins correctly. 

i changed  my code like here :

GPIO_InitTypeDef GPIO_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure; /* GPIOA clock enable */ RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); // RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); /* TIM1 channel 2 pin (PE.11) configuration */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 ; 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_DOWN; GPIO_Init(GPIOB, &GPIO_InitStructure); GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_TIM4); /* Connect TIM pins to AF2 */ //GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_TIM1); TIM_TIxExternalClockConfig(TIM4,TIM_TIxExternalCLK1Source_TI1,TIM_ICPolarity_Rising, 0); // TI1_Config(TIM4,TIM_ICPolarity_Falling,TIM_ICSelection_DirectTI,0); TIM_ETRClockMode1Config(TIM4, TIM_ExtTRGPSC_OFF,TIM_ExtTRGPolarity_Inverted,0); TIM_CounterModeConfig(TIM4,TIM_CounterMode_Up);

TIM_Cmd(TIM4, ENABLE);