Posted on May 17, 2011 at 13:20Hi folks, im trying to get the the stm32 to sample at 1M Samples/sec but only getting max the half .... what is wrong ???
I use Timer1 and DMA to trigger Ad converter. The timer is triggering at 1MHz in this config. I have a scope on the OC1 to check with a scope, that im getting triggered at 1MHz.
i have a 8MHz Xtal, at the pll multiplier is set to 7 = 56Mhz
/f
void InitTIM1(void)
{
TIM_TimeBaseInitTypeDef TIM1_TimeBaseStructure;
TIM_OCInitTypeDef TIM1_OCInitStructure;
TIM1_TimeBaseStructure.TIM_Prescaler = 0;
TIM1_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM1_TimeBaseStructure.TIM_Period = 55; //
TIM1_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM1_TimeBaseStructure.TIM_RepetitionCounter = 0x0;
TIM_TimeBaseInit(TIM1, &TIM1_TimeBaseStructure);
// using a scope to see the frequency ...
TIM1_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM1_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM1_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;
TIM1_OCInitStructure.TIM_Pulse = 10;
TIM1_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
TIM_OC1Init(TIM1,&TIM1_OCInitStructure);
// TIM1 counter enable
TIM_Cmd(TIM1,ENABLE);
// TIM1 main Output Enable
TIM_CtrlPWMOutputs(TIM1,ENABLE);
}
AD Setup...
void ADC_init(void)
{
ADC_InitTypeDef ADC_InitStructure;
ADC_DeInit(ADC1);
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1;
ADC_Init( ADC1, &ADC_InitStructure );
// ADC1 Regular Channel 2 Configuration
ADC_RegularChannelConfig( ADC1, ADC_Channel_8, 1, ADC_SampleTime_1Cycles5);
// Enable ADC1 DMA
ADC_DMACmd(ADC1, ENABLE);
// Enable ADC1 external trigger
ADC_ExternalTrigConvCmd(ADC1, ENABLE);
// Enable ADC1
ADC_Cmd(ADC1, ENABLE);
}
DMA setup :
void DMA_init(void)
{
DMA_InitTypeDef DMA_InitStructure;
// Reconfig the DMA channel 1
//DMA_DeInit(DMA1);
DMA_DeInit(DMA1_Channel1_BASE );
DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&ECG_Buff[0];
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = ECG_BUFF_SIZE;
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_Low;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init( DMA1_Channel1_BASE, &DMA_InitStructure );
// Enable DMA Channel1 Transfer half and Complete interrupt
// DMA_ITConfig(DMA1_Channel1_BASE, DMA_IT_TC | DMA_IT_HT, ENABLE);
DMA_ITConfig(DMA1_Channel1_BASE, DMA_IT_TC , ENABLE);
// Enable DMA Channel1
DMA_Cmd( DMA1_Channel1_BASE, ENABLE );
}
void RCC_Configuration(void)
{
RCC_DeInit();
RCC_HSEConfig(RCC_HSE_ON);
HSEStartUpStatus = RCC_WaitForHSEStartUp();
if(HSEStartUpStatus == SUCCESS)
{
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
FLASH_SetLatency(FLASH_Latency_2);
RCC_HCLKConfig(RCC_SYSCLK_Div1);
RCC_PCLK2Config(RCC_HCLK_Div1);
RCC_PCLK1Config(RCC_HCLK_Div2);
RCC_ADCCLKConfig(RCC_PCLK2_Div4);
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_7);
RCC_PLLCmd(ENABLE);
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
{
}
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
while(RCC_GetSYSCLKSource() != 0x08)
{
}
}
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1 , ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_TIM1 | RCC_APB2Periph_USART1|
RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC, ENABLE);
}
