STM32F405 ADC Project

[amador]

Posted on April 28, 2015 at 00:33

Hello,

I am new to mcu programming and am working on a drone project which uses the STM32F

https://wiki.bitcraze.io/_media/projects:crazyflie2:expansionboards:connector_multiplexing.png?w=900&tok=9c624c

is how the pins are laid out on this drone. I am using pin PA7 which according the the datasheet for this mcu, it is correlated to ADC Channel 7. When reading the converted values, I do see that there is a voltage, but when I apply heat to the sensor I do not see any changes to the values.

static bool isInit = false;

static float temp;

static float vref;


void tmp36Task(void *param);


void tmp36Init()

{

if (isInit) return;


/* Define ADC init structures */

ADC_InitTypeDef ADC_InitStructure;

ADC_CommonInitTypeDef ADC_CommonInitStructure;

GPIO_InitTypeDef GPIO_InitStructure;


/* IMPORTANT: populates structures with reset values */

ADC_StructInit(&ADC_InitStructure);

ADC_CommonStructInit(&ADC_CommonInitStructure);


/* enable ADC clock */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);


/* init GPIO */

GPIO_StructInit(&GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;

GPIO_InitStructure.GPIO_Speed = GPIO_Low_Speed;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

GPIO_Init(GPIOA, &GPIO_InitStructure);


/* init ADCs in independent mode, div clock by two */

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);


/* init ADC1: 12bit, single-conversion */

ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;

ADC_InitStructure.ADC_ScanConvMode = DISABLE;

ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;

ADC_InitStructure.ADC_ExternalTrigConvEdge = 0;

ADC_InitStructure.ADC_ExternalTrigConv = 0;

ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;

ADC_InitStructure.ADC_NbrOfConversion = 1;

ADC_Init(ADC1, &ADC_InitStructure);


/* Enable VREF_INT & Temperature channel */

ADC_TempSensorVrefintCmd(ENABLE);


/* Enable ADC1 **************************************************************/

ADC_Cmd(ADC1, ENABLE);


xTaskCreate(tmp36Task, (const signed char * const)''tmp36'',

configMINIMAL_STACK_SIZE, NULL, 3, NULL);


isInit = true;

}


bool tmp36Test(void)

{

return isInit;

}


float adc_read(ADC_TypeDef* ADCx, uint8_t channel, uint8_t ADC_SampleTime) {

/* Configure Channel */

ADC_RegularChannelConfig(ADCx, channel, 1, ADC_SampleTime);


/* check if conversion was started, if not start */

ADC_SoftwareStartConv(ADCx);


/* wait for end of conversion */

while((ADC_GetFlagStatus(ADCx, ADC_FLAG_EOC) == RESET));


return (float)ADC_GetConversionValue(ADCx);

}


void tmp36Task(void *param)

{

float val;

float mv;

float steps;


vTaskSetApplicationTaskTag(0, (void*)TASK_ADC_ID_NBR);

vTaskDelay(1000);


while(1)

{

val = adc_read(ADC1, ADC_Channel_7, ADC_SampleTime_480Cycles); //TMP36

vref = adc_read(ADC1, ADC_Channel_17, ADC_SampleTime_480Cycles);


//For onboard temp sensor (not TMP36)

steps = (vref * 10) / 12;

mv = (val * 1000) / steps;

temp = (mv - 500) / 10;

}

}

The sensor that I am testing with is the

https://learn.adafruit.com/downloads/pdf/tmp36-temperature-sensor.pdf

temperature sensor. #adc #gpio #adc_channel

[raptorhal2]

Posted on April 28, 2015 at 04:00

Your words say PA7 but your code says PA6.

Cheers, Hal