/******************************************************************//**
* @brief
* Initialize all ADC module related hardware and register ADC device to kernel
*
* @details
*
* @note
*
*********************************************************************/
void rt_hw_adc_init(void)
{
struct efm32_adc_device_t *adc;
ADC_Init_TypeDef init = ADC_INIT_DEFAULT;
// TODO: Fixed oversampling rate?
init.ovsRateSel = adcOvsRateSel4096;
init.timebase = ADC_TimebaseCalc(0);
init.prescale = ADC_PrescaleCalc(ADC_CONVERT_FREQUENCY, 0);
#ifdef RT_USING_ADC0
adc = rt_malloc(sizeof(struct efm32_adc_device_t));
if (adc == RT_NULL)
{
#ifdef RT_ADC_DEBUG
rt_kprintf("no memory for ADC driver\n");
#endif
return;
}
adc->adc_device = ADC0;
adc->mode = ADC_MODE_SINGLE;
/* Enable clock for ADCn module */
CMU_ClockEnable(cmuClock_ADC0, true);
/* Reset */
ADC_Reset(ADC0);
/* Configure ADC */
ADC_Init(adc->adc_device, &init);
rt_hw_adc_register(&adc0_device, RT_ADC0_NAME, EFM32_NO_DATA, adc);
#endif
}
/*
*Function name: DMA_CallBack()
*Description : Call back function of the DMA
*/
void DMA_CallBack(unsigned int channel, bool primary, void *user)
{
unblockSleepMode(EM1);
blockSleepMode(EM2);
if(!trfComplete)
{
ADC_Reset(ADC0); // Reset the ADC; Turn it off
//ADC0->CMD = ADC_CMD_SINGLESTOP;
int temp = 0, i = 0;
char tempChar[7]; //To store the temperature in char, for transmitting
char temp_string[TX_bufferSize];
(void) channel;
(void) primary;
(void) user;
for (i = 0; i < ADC_SAMPLES; i++)
{
temp += (ADC_Buffer[i]);
}
temperature = temp / ADC_SAMPLES;
temperature = convertToCelsius(temperature); //Get value of Temperature in deg C
if (temperature > HIGHTEMP)
{
//GPIO_PinOutClear(gpioPortE,2);
//GPIO_PinOutSet(gpioPortE,3);
/* To extract the digits of the temperature variable and put in tempChar. A basic digit extraction algorithm is used and then each digit is passed one by one. */
temp = temperature*10;
tempChar[0] = (temp/100)+48;
temp = temp%100;
tempChar[1] = (temp/10)+48;
temp = temp%10;
tempChar[2] = '.';
tempChar[3] = (temp)+48;
tempChar[4] = 'C'; // Pad the 4th position of charTemp as C
tempChar[5] = '\r'; // Pad carriage return
tempChar[6] = '\n'; // Pad line feed
strcpy(temp_string,HighTemp); // Copy the HighTemp message in the temporary string
strcat(temp_string,tempChar); // Concatenate with the tempChar to get the final message
LEUART0->CTRL |= LEUART_CTRL_TXDMAWU; // Enable DMA wake up for LEUART TX in EM2
// Activate DMA transfers for LEUART TX
DMA_ActivateBasic(DMA_CHANNEL_TX, true, false, (void *)&(LEUART0->TXDATA), (void *)temp_string, strlen(temp_string) - 1);
}
else if (temperature < LOWTEMP)
{
//GPIO_PinOutSet(gpioPortE,2);
//GPIO_PinOutClear(gpioPortE,3);
temp = temperature*10;
tempChar[0] = (temp/100)+48;
temp = temp%100;
tempChar[1] = (temp/10)+48;
temp = temp%10;
tempChar[2] = '.';
tempChar[3] = (temp)+48;
tempChar[4] = 'C';
tempChar[5] = '\r';
tempChar[6] = '\n';
strcpy(temp_string,LowTemp); // Copy the LowTemp message in the temporary string
strcat(temp_string,tempChar); // Concatenate with the tempChar to get the final message
LEUART0->CTRL |= LEUART_CTRL_TXDMAWU; // Enable DMA wake up for LEUART TX in EM2
// Activate DMA transfers for LEUART TX
DMA_ActivateBasic(DMA_CHANNEL_TX, true, false, (void *)&(LEUART0->TXDATA), (void *)temp_string, strlen(temp_string) -1);
}
trfComplete=true;
}
else
{
(void) channel;
(void) primary;
(void) user;
// Disable DMA wake-up from LEUART1 TX
LEUART0->CTRL &= ~LEUART_CTRL_TXDMAWU;
}
}
/***************************************************************************//**
* @brief
* Calibrate offset and gain for the specified reference.
* Supports currently only single ended gain calibration.
* Could easily be expanded to support differential gain calibration.
*
* @details
* The offset calibration routine measures 0 V with the ADC, and adjust
* the calibration register until the converted value equals 0.
* The gain calibration routine needs an external reference voltage equal
* to the top value for the selected reference. For example if the 2.5 V
* reference is to be calibrated, the external supply must also equal 2.5V.
*
* @param[in] adc
* Pointer to ADC peripheral register block.
*
* @param[in] ref
* Reference used during calibration. Can be both external and internal
* references.
*
* @return
* The final value of the calibration register, note that the calibration
* register gets updated with this value during the calibration.
* No need to load the calibration values after the function returns.
******************************************************************************/
uint32_t ADC_Calibration(ADC_TypeDef *adc, ADC_Ref_TypeDef ref)
{
int32_t sample;
uint32_t cal;
/* Binary search variables */
uint8_t high;
uint8_t mid;
uint8_t low;
/* Reset ADC to be sure we have default settings and wait for ongoing */
/* conversions to be complete. */
ADC_Reset(adc);
ADC_Init_TypeDef init = ADC_INIT_DEFAULT;
ADC_InitSingle_TypeDef singleInit = ADC_INITSINGLE_DEFAULT;
/* Init common settings for both single conversion and scan mode */
init.timebase = ADC_TimebaseCalc(0);
/* Might as well finish conversion as quickly as possibly since polling */
/* for completion. */
/* Set ADC clock to 7 MHz, use default HFPERCLK */
init.prescale = ADC_PrescaleCalc(7000000, 0);
/* Set an oversampling rate for more accuracy */
init.ovsRateSel = adcOvsRateSel4096;
/* Leave other settings at default values */
ADC_Init(adc, &init);
/* Init for single conversion use, measure diff 0 with selected reference. */
singleInit.reference = ref;
singleInit.input = adcSingleInpDiff0;
singleInit.acqTime = adcAcqTime16;
singleInit.diff = true;
/* Enable oversampling rate */
singleInit.resolution = adcResOVS;
ADC_InitSingle(adc, &singleInit);
/* ADC is now set up for offset calibration */
/* Offset calibration register is a 7 bit signed 2's complement value. */
/* Use unsigned indexes for binary search, and convert when calibration */
/* register is written to. */
high = 128;
low = 0;
/* Do binary search for offset calibration*/
while (low < high)
{
/* Calculate midpoint */
mid = low + (high - low) / 2;
/* Midpoint is converted to 2's complement and written to both scan and */
/* single calibration registers */
cal = adc->CAL & ~(_ADC_CAL_SINGLEOFFSET_MASK | _ADC_CAL_SCANOFFSET_MASK);
cal |= (mid - 63) << _ADC_CAL_SINGLEOFFSET_SHIFT;
cal |= (mid - 63) << _ADC_CAL_SCANOFFSET_SHIFT;
adc->CAL = cal;
/* Do a conversion */
ADC_Start(adc, adcStartSingle);
/* Wait while conversion is active */
while (adc->STATUS & ADC_STATUS_SINGLEACT) ;
/* Get ADC result */
sample = ADC_DataSingleGet(adc);
/* Check result and decide in which part of to repeat search */
/* Calibration register has negative effect on result */
if (sample < 0)
{
/* Repeat search in bottom half. */
high = mid;
}
else if (sample > 0)
{
/* Repeat search in top half. */
low = mid + 1;
}
else
{
/* Found it, exit while loop */
break;
}
}
/* Now do gain calibration, only input and diff settings needs to be changed */
adc->SINGLECTRL &= ~(_ADC_SINGLECTRL_INPUTSEL_MASK | _ADC_SINGLECTRL_DIFF_MASK);
adc->SINGLECTRL |= (adcSingleInpCh4 << _ADC_SINGLECTRL_INPUTSEL_SHIFT);
adc->SINGLECTRL |= (false << _ADC_SINGLECTRL_DIFF_SHIFT);
/* ADC is now set up for gain calibration */
/* Gain calibration register is a 7 bit unsigned value. */
high = 128;
low = 0;
/* Do binary search for gain calibration */
while (low < high)
{
/* Calculate midpoint and write to calibration register */
mid = low + (high - low) / 2;
/* Midpoint is converted to 2's complement */
cal = adc->CAL & ~(_ADC_CAL_SINGLEGAIN_MASK | _ADC_CAL_SCANGAIN_MASK);
cal |= mid << _ADC_CAL_SINGLEGAIN_SHIFT;
cal |= mid << _ADC_CAL_SCANGAIN_SHIFT;
adc->CAL = cal;
/* Do a conversion */
ADC_Start(adc, adcStartSingle);
/* Wait while conversion is active */
while (adc->STATUS & ADC_STATUS_SINGLEACT) ;
/* Get ADC result */
sample = ADC_DataSingleGet(adc);
/* Check result and decide in which part to repeat search */
/* Compare with a value atleast one LSB's less than top to avoid overshooting */
/* Since oversampling is used, the result is 16 bits, but a couple of lsb's */
/* applies to the 12 bit result value, if 0xffe is the top value in 12 bit, this */
/* is in turn 0xffe0 in the 16 bit result. */
/* Calibration register has positive effect on result */
if (sample > 0xffd0)
{
/* Repeat search in bottom half. */
high = mid;
}
else if (sample < 0xffd0)
{
/* Repeat search in top half. */
low = mid + 1;
}
else
{
/* Found it, exit while loop */
break;
}
}
return adc->CAL;
}
