STM32F30x ADC dual regular simult. mode, 8 bit

[tomasz2399]

Posted on June 01, 2013 at 21:24

Hello,

I'm trying to run STM32F30x ADC in dual regular simultaneous 8-bit mode and I would like to ask for help. My MCU is STM32F303CBT6, rev. Y, I'm using ADC 1+2 for PA0 and PA4 sampling respectively. Unfortunately I'm must be missing something because I'm getting samples only from first (PA0) channel (or from PA4 if

ADC_RegularChannelConfig

calls order is reversed). Samples from second channel are equal to zero. Here is my ADC/DMA initialization:

enum
{ ADC_HALF_BUFFER = 512 };
unsigned 
int
ADCbuf[2*ADC_HALF_BUFFER];
static
void
setup_adc_gpio(
void
)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable GPIOA Periph clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* Configure ADC1/2 channels as analog input */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
static
void
setup_adc_dma(
void
)
{
DMA_InitTypeDef DMA_InitStructure;
/* Enable DMA1 clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
/* DMA1 Channel1 Init */
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1_2->CDR;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; 
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADCbuf;
DMA_InitStructure.DMA_BufferSize = 
sizeof
(ADCbuf)/
sizeof
(ADCbuf[0]);
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word; 
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
/* DMA interrupts */
DMA_ITConfig(DMA1_Channel1, DMA_IT_TC | DMA_IT_HT, ENABLE);
/* enable DMA IRQ */
NVIC_EnableIRQ(DMA1_Channel1_IRQn);
} 
static
void
calibrate_adc(
void
)
{
__IO uint16_t calibration_value_1 = 0; 
///< __IO = volatile 
__IO uint16_t calibration_value_2 = 0; 
/* ADC Calibration procedure */
ADC_VoltageRegulatorCmd(ADC1, ENABLE);
ADC_VoltageRegulatorCmd(ADC2, ENABLE);
/* Insert delay equal to 10 µs */
SystickDelay(10);
ADC_SelectCalibrationMode(ADC1, ADC_CalibrationMode_Single);
ADC_StartCalibration(ADC1);
ADC_SelectCalibrationMode(ADC2, ADC_CalibrationMode_Single);
ADC_StartCalibration(ADC2);
while
(ADC_GetCalibrationStatus(ADC1) != RESET );
calibration_value_1 = ADC_GetCalibrationValue(ADC1);
while
(ADC_GetCalibrationStatus(ADC2) != RESET );
calibration_value_2 = ADC_GetCalibrationValue(ADC2); 
}
void
setup_adc(adc_data_cb on_adc_data)
{
ADC_CommonInitTypeDef ADC_CommonInitStructure;
ADC_InitTypeDef ADC_InitStructure;
adc_data_callback = on_adc_data;
/* Configure the ADC clock */
RCC_ADCCLKConfig(RCC_ADC12PLLCLK_Div64); 
/* Enable ADC1 clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_ADC12, ENABLE);
setup_adc_gpio();
setup_adc_dma();
/* Setup SysTick Timer for 1 µsec interrupts */
if
(SysTick_Config(SystemCoreClock / 1000000))
{ 
Buzzer_On();
/* Capture error */
while
(1)
{}
} 
calibrate_adc();
ADC_CommonStructInit(&ADC_CommonInitStructure);
ADC_CommonInitStructure.ADC_Mode = ADC_Mode_RegSimul; 
ADC_CommonInitStructure.ADC_Clock = ADC_Clock_AsynClkMode; 
//ADC_Clock_SynClkModeDiv1
ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1 ; 
// ADC_DMAAccessMode_2
ADC_CommonInitStructure.ADC_DMAMode = ADC_DMAMode_Circular; 
ADC_CommonInitStructure.ADC_TwoSamplingDelay = 0; 
ADC_CommonInit(ADC1, &ADC_CommonInitStructure);
/* ADC setup */
ADC_StructInit(&ADC_InitStructure);
ADC_InitStructure.ADC_ContinuousConvMode = ADC_ContinuousConvMode_Enable;
ADC_InitStructure.ADC_Resolution = ADC_Resolution_8b; 
ADC_InitStructure.ADC_ExternalTrigConvEvent = ADC_ExternalTrigConvEvent_0; 
ADC_InitStructure.ADC_ExternalTrigEventEdge = ADC_ExternalTrigEventEdge_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_OverrunMode = ADC_OverrunMode_Disable; 
ADC_InitStructure.ADC_AutoInjMode = ADC_AutoInjec_Disable; 
ADC_InitStructure.ADC_NbrOfRegChannel = 1;
ADC_Init(ADC1, &ADC_InitStructure);
ADC_Init(ADC2, &ADC_InitStructure);
ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_7Cycles5);
ADC_RegularChannelConfig(ADC2, ADC_Channel_5, 1, ADC_SampleTime_7Cycles5); 
/* Configures the ADC DMA */
ADC_DMAConfig(ADC1, ADC_DMAMode_Circular);
/* Enable the ADC DMA */
ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 and ADC2 */
ADC_Cmd(ADC1, ENABLE);
ADC_Cmd(ADC2, ENABLE);
/* wait for ADC1 ADRDY */
while
(!ADC_GetFlagStatus(ADC1, ADC_FLAG_RDY));
/* wait for ADC2 ADRDY */
while
(!ADC_GetFlagStatus(ADC2, ADC_FLAG_RDY)); 
/* Enable the DMA channel */
DMA_Cmd(DMA1_Channel1, ENABLE);
/* Start ADC1 Software Conversion */
ADC_StartConversion(ADC1);
}

Whole Keil project (packed with 7-zip) - kind of basic USB oscilloscope:

http://tomeko.net/tmp/miniscope_v2d_2013067z

[tomasz2399]

Posted on June 16, 2013 at 09:52

The problem was misunderstanding of pins to ADC channels mapping - pin PA4 represents first channel of ADC2.

If anyone is interested complete project (USB oscilloscope + arbitrary generator) documentation is available at 

http://tomeko.net/miniscope_v2d/

.