Using external clock for adc triggered

[sanjib]

Posted on February 06, 2014 at 04:42

How to use external clock for adc triggered. Any help will be highly appreciated

[Tesla DeLorean]

Posted on February 06, 2014 at 05:43

I'd suppose you could connect TIMx_CHx pins in input capture mode, and use those, or check the configuration options for EXTI line mappings.

[sanjib]

Posted on February 06, 2014 at 13:34

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[sanjib]

Posted on February 06, 2014 at 13:36

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[sanjib]

Posted on February 06, 2014 at 14:32

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[Tesla DeLorean]

Posted on February 06, 2014 at 15:57

Here's at tip, when testing new ideas keep the code very simple, when you've proved the method integrate it back into your more complicated structure.

GPIO_PinAFConfig(GPIOB, GPIO_PinSource12, GPIO_AF_TIM4); // Needs to be GPIOD for PD12

[sanjib]

Posted on February 07, 2014 at 05:27

Thanks Clive

I will really implement your tip in my next experiment.

I have made the change which you have seen. If Timer3 received external clock pulse from timer4 the adc will get triggered and enter  DMA2_Stream0_IRQHandler . For test purpose I have made the LED on but it not glowing. DAC,DMA and ADC was working fine with TRIGGER Internally, I just made change in output compare (TIM 4) ,Input capture (TIME 3) , Configure related pins and this line 

ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T3_CC1  ; After tha it's not working. Please say me what wrong I am doing

[sanjib]

Posted on February 07, 2014 at 13:15

Please Help clive. I need it badly

[sanjib]

Posted on February 10, 2014 at 04:58

I don't know what misake I am doing please help me anybody

[Tesla DeLorean]

Posted on February 10, 2014 at 17:07

I don't have the time to wade through your code. I can however demonstrate clocking an ADC from an external source.

// STM32 ADC Sample @ 200 KHz (PC.1) STM32F4 Discovery - [e-mail]
// Strap PC6 (200 KHz) to PA15 (Trigger)
// Assumptions per system_stm32f4xx.c CPU @ 168 MHz, APB2 @ 84 MHz (/2), APB1 @ 42 MHz (/4)
#include ''stm32f4_discovery.h''
/**************************************************************************************/
void RCC_Configuration(void)
{
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOC, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3, ENABLE);
}
/**************************************************************************************/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
// ADC Channel 11 -> PC1
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOC, &GPIO_InitStructure);
// TIM2_CH1 PA15
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
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(GPIOA, &GPIO_InitStructure);
/* Connect TIM2 pins to AF */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource15, GPIO_AF_TIM2); // CH1
// TIM3_CH1 PC6 200 KHz Clock Source Output
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
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(GPIOC, &GPIO_InitStructure);
/* Connect TIM3 pins to AF */
GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_TIM3); // CH1
}
/**************************************************************************************/
void ADC_Configuration(void)
{
ADC_CommonInitTypeDef ADC_CommonInitStructure;
ADC_InitTypeDef ADC_InitStructure;
/* ADC Common Init */
ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
ADC_CommonInit(&ADC_CommonInitStructure);
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
ADC_InitStructure.ADC_ScanConvMode = DISABLE; // 1 Channel
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE; // Conversions Triggered
ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_Rising;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T2_TRGO;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfConversion = 1;
ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channel 11 configuration */
ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_15Cycles); // PC1
/* Enable DMA request after last transfer (Single-ADC mode) */
ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);
/* Enable ADC1 DMA */
ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 */
ADC_Cmd(ADC1, ENABLE);
}
/**************************************************************************************/
#define BUFFERSIZE 400 // 200KHz x2 HT/TC at 1KHz
__IO uint16_t ADCConvertedValues[BUFFERSIZE];
static void DMA_Configuration(void)
{
DMA_InitTypeDef DMA_InitStructure;
DMA_InitStructure.DMA_Channel = DMA_Channel_0;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADCConvertedValues[0];
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStructure.DMA_BufferSize = BUFFERSIZE; // Count of 16-bit words
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA2_Stream0, &DMA_InitStructure);
/* Enable DMA Stream Half / Transfer Complete interrupt */
DMA_ITConfig(DMA2_Stream0, DMA_IT_TC | DMA_IT_HT, ENABLE);
/* DMA2_Stream0 enable */
DMA_Cmd(DMA2_Stream0, ENABLE);
}
/**************************************************************************************/
void TIM2_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_ICInitTypeDef TIM_ICInitStructure;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = -1; // Maximal
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
/* Configure Input Capture */
TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; // PA15 TIM2_CH1
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 = 0x0;
TIM_ICInit(TIM2, &TIM_ICInitStructure);
/* TIM2 TRGO selection */
TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_OC1); // ADC_ExternalTrigConv_T2_TRGO
/* TIM2 enable counter */
TIM_Cmd(TIM2, ENABLE);
}
/**************************************************************************************/
void TIM3_Configuration(void)
{
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
uint16_t Period, Prescaler;
Prescaler = 1;
Period = ((SystemCoreClock / 2) / 200000) - 1; // 200 KHz, from 84 MHz TIM3CLK (ie APB1 = HCLK/4, TIM3CLK = HCLK/2)
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = Period - 1;
TIM_TimeBaseStructure.TIM_Prescaler = Prescaler - 1;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* TIM PWM1 Mode configuration */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = Period / 4; // 25%
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
/* Output Compare PWM1 Mode configuration: Channel 1 */
TIM_OC1Init(TIM3, &TIM_OCInitStructure);
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);
}
/**************************************************************************************/
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
/* Enable the DMA Stream IRQ Channel */
NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/**************************************************************************************/
void DMA2_Stream0_IRQHandler(void) // Called at 1 KHz for 200 KHz sample rate, LED Toggles at 500 Hz
{
/* Test on DMA Stream Half Transfer interrupt */
if (DMA_GetITStatus(DMA2_Stream0, DMA_IT_HTIF0))
{
/* Clear DMA Stream Half Transfer interrupt pending bit */
DMA_ClearITPendingBit(DMA2_Stream0, DMA_IT_HTIF0);
/* Turn LED3 off: Half Transfer */
STM_EVAL_LEDOff(LED3);
// Add code here to process first half of buffer (ping)
}
/* Test on DMA Stream Transfer Complete interrupt */
if (DMA_GetITStatus(DMA2_Stream0, DMA_IT_TCIF0))
{
/* Clear DMA Stream Transfer Complete interrupt pending bit */
DMA_ClearITPendingBit(DMA2_Stream0, DMA_IT_TCIF0);
/* Turn LED3 on: End of Transfer */
STM_EVAL_LEDOn(LED3);
// Add code here to process second half of buffer (pong)
}
}
/**************************************************************************************/
int main(void)
{
RCC_Configuration();
GPIO_Configuration();
NVIC_Configuration();
TIM2_Configuration(); // Input Capture - External ADC Trigger Source - PA15
TIM3_Configuration(); // Test bench clock source on PC6
DMA_Configuration();
ADC_Configuration();
STM_EVAL_LEDInit(LED3); // Configure LEDs to monitor program status
STM_EVAL_LEDOn(LED3); // Turn LED3 on, 500 Hz means it working
ADC_SoftwareStartConv(ADC1); // Start ADC1 Software Conversion
while(1); // Don't want to exit
}
/**************************************************************************************/
#ifdef 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

'', file, line) */
/* Infinite loop */
while (1)
{
}
}
#endif
/**************************************************************************************/

[sanjib]

Posted on February 11, 2014 at 06:38

Thanks a lot clive.

You are really a master