I have a problem and currently no clue how to further debug. Maybe one coudl help me.
I use STM32f4 to capture with ADC1 3 signals with 1Mhz (so 333kHz per channel) triggered by a timer and transfered via DMA. I have a DMA buffer of 3*2*100 (so 100 samples per channel per half DMA). When DMA is Half/Full filed, I store the data in a second buffer with 10 times 100 samples. Using a test sin signal ~23kHz, I get discontinuities at each 100 sample border.
I check the code several times but could not find an error and it seams like ADC sampling is kind of pausing at each DMA Half/Full callback call (which seams not plausible)
BR, BastelBaus
The faulty output with discontinuities each 100 samples:
Timer configuration (96Mhz clock)
ADC configuration
Init the ADC and callbacks
void ADC_init(void) {
HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1); // ADC trigger
HAL_ADC_Start_DMA(&hadc1,(uint32_t*)&adc_samples,ADC_N );
} // void ADC_init(void) {// Called when first half of buffer is filled
void HAL_ADC_ConvHalfCpltCallback(ADC_HandleTypeDef* hadc) {
if (new_data != NULL) buffer_overrun = true;
new_data = first_half_adc_buffer;
} // void HAL_ADC_ConvHalfCpltCallback(ADC_HandleTypeDef* hadc) {
// Called when buffer is completely filled
void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc) {
if (new_data != NULL) buffer_overrun = true;
new_data = second_half_adc_buffer;
} // void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc) {
Buffereing 10 frames and transmitting over UART
bool transmitting_data = false;
#define ADC_SAMPLE_PATCHES 10
uint16_t adc_patch_buffer[ADC_SAMPLE_PATCHES][ADC_N/2];
int patch_i = 0;
void ADC_clb_process_adc_data(volatile uint16_t* source_adr, size_t samples) {
//print_debug("ADC_clb_process_adc_data: samples=%d\n",samples);
if (transmitting_data) return;
memcpy(adc_patch_buffer[patch_i],source_adr,samples*sizeof(uint16_t));
patch_i = (patch_i+1)%ADC_SAMPLE_PATCHES;
return;
} // void CLB_process_adc_data(void) {
void print_adc_raw_data(CHANNEL_t channel, PARAMETER_t par) {
transmitting_data = true;
uint8_t channels[3] = {CHANNEL_X,CHANNEL_Y,CHANNEL_Z};
// output each channel
for(uint8_t k=0;k<3;k++)
if (channel == channels[k] || channel == CHANNEL_ALL) {
print_adc("");
for(uint8_t a=0;a<ADC_SAMPLE_PATCHES-1;a++) {
uint8_t b = (a+patch_i+1)%ADC_SAMPLE_PATCHES;
for(int i=0;i<ADC_N/3/2;i++) printf("%d;",adc_patch_buffer[b][i*3+k]);
}
printf("\n");
fflush(stdout);
HAL_Delay(100); // TODO: check this, nbeeded to have it stable ???
}
}
fflush(stdout);
transmitting_data = false;
} // void print_adc_raw_data(CHANNEL_t channel, PARAMETER_t par) {
