Let's Decode some ADC+DMA output

Could you use the same sample time for both tests?

Could you use the same sample time for both tests?

What's the pin tied too?

What values do you see if you tie the pin to either rail?

The second half of the buffer starts at [100] not [99]

Ment ADC_SampleTime_15Cycles vs ADC_SampleTime_144Cycles

Having trouble saving my text here. Site is really slow today.

Not sure I have any 446 Nucleo's

I tried all the other channels on ADC1. All channels read 30. Except for CH16,17,18 which always read 12. Enabling the temp sensor on ch18 give believable values.

Channel 13 is PC3, not PC0.

Alright, I've narrowed it down to a couple settings. Check this out.

/* Includes ------------------------------------------------------------------*/
#include ''main.h''
#include ''stdint.h''
#include ''stdlib.h''
#include ''stdio.h''
#include ''string.h''
#include ''ccd.h''
#include ''adc.h''
#include ''usart.h''
#include ''utils.h''
uint32_t i;
uint16_t j;
uint16_t sample = 0;
uint32_t done = 0;
volatile

uint16_t ADCConvertedValues[NUM_SAMPLES] = {0};
volatile

uint16_t

signal

[NUM_SAMPLES] = {0};
int

main(

void

)
{
done = 0;
LED_Setup();
GPIO_Setup();
RCC_Configuration();
USART3_Configuration();
GPIO(0);
LED(1);
/* Define ADC init structures */
ADC_InitTypeDef ADC_InitStructure;
ADC_CommonInitTypeDef ADC_CommonInitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
/* Enable timer (timer runs at 90 MHz)*/
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_Period = 449999;
TIM_TimeBaseStructure.TIM_Prescaler = 1;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
TIM_SelectOutputTrigger(TIM2,TIM_TRGOSource_Update);
//TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
NVIC_Init(&NVIC_InitStructure);
/* Enable clock on DMA1 & GPIOC */
/* Enable DMA2, thats where ADC is hooked on -> see Tab 20 (RM00090) */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_DMA2, ENABLE);
/* Initialise GPIOs C0 (ADC123_IN10), C1 (ADC123_IN11), C2 (ADC123_IN12)*/
GPIO_StructInit(&GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* Initialise DMA */
DMA_StructInit(&DMA_InitStructure);
/* config of DMAC */
DMA_InitStructure.DMA_Channel = DMA_Channel_0;

/* See Tab 20 */

DMA_InitStructure.DMA_BufferSize = 200;

/* 200 * memsize */

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;

/* direction */

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;

/* no FIFO */

DMA_InitStructure.DMA_FIFOThreshold = 0;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;

/* circular buffer */

DMA_InitStructure.DMA_Priority = DMA_Priority_High;

/* high priority */

/* config of memory */
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADCConvertedValues[0];

/* target addr */

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

/* 16 bit */

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_Init(DMA2_Stream0, &DMA_InitStructure);

/* See Table 20 for mapping */

DMA_Cmd(DMA2_Stream0, ENABLE);
DMA_ITConfig(DMA2_Stream0, DMA_IT_TC | DMA_IT_HT, ENABLE);
DMA_Cmd(DMA2_Stream0, ENABLE);
/* IMPORTANT: populate default values before use */
ADC_StructInit(&ADC_InitStructure);
ADC_CommonStructInit(&ADC_CommonInitStructure);
/* reset configuration if needed, could be used for previous init */
ADC_Cmd(ADC1, DISABLE);
ADC_DeInit();
/* init ADC clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
/* init ADC */
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);
/* ADC1 Init: this is mostly done with ADC1->CR */
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
ADC_InitStructure.ADC_ScanConvMode = ENABLE;
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
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 = 2;

/* 2 channels in total */

ADC_Init(ADC1, &ADC_InitStructure);
/* Enable Vref & Temperature channel */
ADC_TempSensorVrefintCmd(ENABLE);
/* Configure channels */
ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_480Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_18, 2, ADC_SampleTime_480Cycles);
/* 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);
/* in main */
TIM_Cmd(TIM2, ENABLE);
while

(1)
{
//printf(''%d, %d, %d, %d, %d

'', ADCConvertedValues[0], ADCConvertedValues[1], ADCConvertedValues[2], ADCConvertedValues[3], ADCConvertedValues[4]);
for

(i = 0; i < 100000000; i++)
{
}
for

(i = 1; i < 200; i++)
{
printf

(

''block[%d] = %d, 

''

, i, ADCConvertedValues[i+1]);
i++;
}
for

(i = 0; i < 20000000; i++)
{
}
while

(1);
}
}
void

DMA2_Stream0_IRQHandler(

void

)

// Called at 2 Hz for 200 Hz sample rate, LED Toggles at 2 Hz

{
//uint16_t i = 0;
/* 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 */
GPIO(1);
done = 1;
// Add code here to process first half of buffer (ping)
//DMA_Cmd(DMA2_Stream0, DISABLE);
LED(0);
}
/* 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 */
GPIO(0);
//DMA_Cmd(DMA2_Stream0, DISABLE);
LED(1);
// Add code here to process second half of buffer (pong)
// CountFallingEdges(&ADCConvertedValues[99],NUM_SAMPLES/2);
}
}