ADC , DMA , TIM8 Triggering

[blue_dolphin1987]

Posted on January 03, 2014 at 06:45

Hi,

I am attempting to use timer 8 to trigger adc sampling using stm32f1. I have referred to some example on the forum from Clive1 which is using timer 1 . However the code does not work when i convert to TIM 8 .

void RCC_Configuration(void)
{
RCC_ADCCLKConfig(RCC_PCLK2_Div2);
/* Enable DMA1 clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
/* Enable GPIOs and ADC1 clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC |
RCC_APB2Periph_TIM8 |
RCC_APB2Periph_ADC1, ENABLE);
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure PC.04 (ADC Channel14) as analog input */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
int main(void){
ADC_InitTypeDef ADC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* System clocks configuration ---------------------------------------------*/
RCC_Configuration();
/* GPIO configuration ------------------------------------------------------*/
GPIO_Configuration();
RCC_ADCCLKConfig(RCC_PCLK2_Div2);
/* Enable peripheral clocks ------------------------------------------------*/
/* Enable DMA1 clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
/* Enable GPIOA, GPIOC, ADC1 and TIM1 clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC |
RCC_APB2Periph_ADC1 | RCC_APB2Periph_TIM8, ENABLE);
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure); 
TIM_TimeBaseStructure.TIM_Period = 0xFF; 
TIM_TimeBaseStructure.TIM_Prescaler = 0x4; 
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0; 
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);
/* TIM1 channel1 configuration in PWM mode */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; 
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; 
TIM_OCInitStructure.TIM_Pulse = 0x7F; 
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; 
TIM_OC1Init(TIM8, &TIM_OCInitStructure);
TIM_SelectOutputTrigger(TIM8, TIM_TRGOSource_Update);
/* DMA1 Channel1 Configuration ----------------------------------------------*/
DMA_DeInit(DMA1_Channel1);
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)Temp_Data;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = 8;
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_Word;
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
/* Enable DMA1 channel1 */
DMA_Cmd(DMA1_Channel1, ENABLE);
/* ADC1 configuration ------------------------------------------------------*/
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_Ext_IT11_TIM8_TRGO;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1;
ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channel14 configuration */ 
ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_13Cycles5);
/* Enable ADC1 DMA */
ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 external trigger */ 
ADC_ExternalTrigConvCmd(ADC1, ENABLE);
/* Enable ADC1 */
ADC_Cmd(ADC1, ENABLE);
/* Enable ADC1 reset calibration register */ 
ADC_ResetCalibration(ADC1);
/* Check the end of ADC1 reset calibration register */
while(ADC_GetResetCalibrationStatus(ADC1));
/* Start ADC1 calibration */
ADC_StartCalibration(ADC1);
/* Check the end of ADC1 calibration */
while(ADC_GetCalibrationStatus(ADC1));
/* TIM1 counter enable */
TIM_Cmd(TIM8, ENABLE);
/* TIM1 main Output Enable */
TIM_CtrlPWMOutputs(TIM8, ENABLE); 
while(1){
/* Test on channel1 transfer complete flag */
while(!DMA_GetFlagStatus(DMA1_FLAG_TC1));
/* Clear channel1 transfer complete flag */
DMA_ClearFlag(DMA1_FLAG_TC1); 
}
}

In the reference manual page 173 it is mentioned that The selection of the external trigger EXTI line11 or TIM8_TRGO event for regular channels is done throughconfiguration bits ADC1_ETRGREG_REMAP and ADC2_ETRGREG_REMAP for ADC1 and ADC2,respectively. I have selected trigger as ADC_ExternalTrigConv_Ext_IT11_TIM8_TRGO . Thanks .

[raptorhal2]

Posted on January 04, 2014 at 16:19

The F1 series doesn't have a Timer 8.

Cheers, Hal

[blue_dolphin1987]

Posted on January 06, 2014 at 02:14

Hi Hal , 

I am using a High Density Device and it has 2 advanced timer . I have cross check with the datasheet  Low- and medium-density STM32F103xx devices contain one advanced-control timer(TIM1) whereas high-density STM32F103xx devices feature two advance-control timers(TIM1 and TIM8).Cheers,sean

[Amel NASRI]

Posted on January 21, 2014 at 08:23

Hello,

As you are using ADC1_Channel11, you have to enable PC1 not PC4. -Mayla-