453 lines
12 KiB
C
453 lines
12 KiB
C
/******************************************************************//**
|
|
* @file drv_adc.c
|
|
* @brief ADC driver of RT-Thread RTOS for EFM32
|
|
* COPYRIGHT (C) 2011, RT-Thread Development Team
|
|
* @author onelife
|
|
* @version 0.4 beta
|
|
**********************************************************************
|
|
* @section License
|
|
* The license and distribution terms for this file may be found in the file LICENSE in this
|
|
* distribution or at http://www.rt-thread.org/license/LICENSE
|
|
**********************************************************************
|
|
* @section Change Logs
|
|
* Date Author Notes
|
|
* 2011-02-21 onelife Initial creation for EFM32
|
|
*********************************************************************/
|
|
|
|
/******************************************************************//**
|
|
* @addtogroup efm32
|
|
* @{
|
|
*********************************************************************/
|
|
|
|
/* Includes -------------------------------------------------------------------*/
|
|
#include "board.h"
|
|
#include "drv_adc.h"
|
|
|
|
/* Private typedef -------------------------------------------------------------*/
|
|
/* Private define --------------------------------------------------------------*/
|
|
/* Private macro --------------------------------------------------------------*/
|
|
/* Private variables ------------------------------------------------------------*/
|
|
#ifdef RT_USING_ADC0
|
|
static struct rt_device adc0_device;
|
|
#endif
|
|
|
|
/* Private function prototypes ---------------------------------------------------*/
|
|
rt_uint32_t efm32_adc_calibration(
|
|
ADC_TypeDef *adc,
|
|
ADC_Ref_TypeDef ref,
|
|
ADC_SingleInput_TypeDef input);
|
|
|
|
/* Private functions ------------------------------------------------------------*/
|
|
/******************************************************************//**
|
|
* @brief
|
|
* Initialize ADC device
|
|
*
|
|
* @details
|
|
*
|
|
* @note
|
|
*
|
|
* @param[in] dev
|
|
* Pointer to device descriptor
|
|
*
|
|
* @return
|
|
* Error code
|
|
*********************************************************************/
|
|
static rt_err_t rt_adc_init(rt_device_t dev)
|
|
{
|
|
RT_ASSERT(dev != RT_NULL);
|
|
|
|
rt_uint32_t temp;
|
|
|
|
struct efm32_adc_device_t *adc;
|
|
|
|
adc = (struct efm32_adc_device_t *)(dev->user_data);
|
|
|
|
temp = efm32_adc_calibration(adc->adc_device, ADC_INIT_REF, ADC_INIT_CH);
|
|
|
|
#ifdef RT_ADC_DEBUG
|
|
rt_kprintf("adc->CAL = %x\n", temp);
|
|
#endif
|
|
|
|
return RT_EOK;
|
|
}
|
|
|
|
/******************************************************************//**
|
|
* @brief
|
|
* Configure ADC device
|
|
*
|
|
* @details
|
|
*
|
|
* @note
|
|
*
|
|
* @param[in] dev
|
|
* Pointer to device descriptor
|
|
*
|
|
* @param[in] cmd
|
|
* ADC control command
|
|
*
|
|
* @param[in] args
|
|
* Arguments
|
|
*
|
|
* @return
|
|
* Error code
|
|
*********************************************************************/
|
|
static rt_err_t rt_adc_control(
|
|
rt_device_t dev,
|
|
rt_uint8_t cmd,
|
|
void *args)
|
|
{
|
|
RT_ASSERT(dev != RT_NULL);
|
|
|
|
struct efm32_adc_device_t *adc;
|
|
|
|
adc = (struct efm32_adc_device_t *)(dev->user_data);
|
|
|
|
switch (cmd)
|
|
{
|
|
case RT_DEVICE_CTRL_SUSPEND:
|
|
/* Suspend device */
|
|
dev->flag |= RT_DEVICE_FLAG_SUSPENDED;
|
|
adc->adc_device->CMD = ADC_CMD_SINGLESTOP | ADC_CMD_SCANSTOP;
|
|
break;
|
|
|
|
case RT_DEVICE_CTRL_RESUME:
|
|
/* Resume device */
|
|
dev->flag &= ~RT_DEVICE_FLAG_SUSPENDED;
|
|
|
|
switch (adc->mode)
|
|
{
|
|
case ADC_MODE_SINGLE:
|
|
ADC_Start(adc->adc_device, adcStartSingle);
|
|
break;
|
|
|
|
case ADC_MODE_SCAN:
|
|
ADC_Start(adc->adc_device, adcStartScan);
|
|
break;
|
|
|
|
case ADC_MODE_TAILGATE:
|
|
ADC_Start(adc->adc_device, adcStartScanAndSingle);
|
|
break;
|
|
|
|
default:
|
|
return -RT_ERROR;
|
|
}
|
|
break;
|
|
|
|
case RT_DEVICE_CTRL_ADC_MODE:
|
|
{
|
|
/* change device setting */
|
|
struct efm32_adc_control_t *control;
|
|
|
|
control = (struct efm32_adc_control_t *)args;
|
|
|
|
switch (control->mode)
|
|
{
|
|
case ADC_MODE_SINGLE:
|
|
ADC_InitSingle(adc->adc_device, control->singleInit);
|
|
break;
|
|
|
|
case ADC_MODE_SCAN:
|
|
ADC_InitScan(adc->adc_device, control->scanInit);
|
|
break;
|
|
|
|
case ADC_MODE_TAILGATE:
|
|
ADC_InitSingle(adc->adc_device, control->singleInit);
|
|
ADC_InitScan(adc->adc_device, control->scanInit);
|
|
break;
|
|
|
|
default:
|
|
return -RT_ERROR;
|
|
}
|
|
|
|
adc->mode = control->mode;
|
|
}
|
|
break;
|
|
|
|
case RT_DEVICE_CTRL_ADC_RESULT:
|
|
switch (adc->mode)
|
|
{
|
|
case ADC_MODE_SINGLE:
|
|
while (adc->adc_device->STATUS & ADC_STATUS_SINGLEACT);
|
|
*((rt_uint32_t *)args) = ADC_DataSingleGet(adc->adc_device);
|
|
break;
|
|
|
|
case ADC_MODE_SCAN:
|
|
while (adc->adc_device->STATUS & ADC_STATUS_SCANACT);
|
|
*((rt_uint32_t *)args) = ADC_DataScanGet(adc->adc_device);
|
|
break;
|
|
|
|
case ADC_MODE_TAILGATE:
|
|
while (adc->adc_device->STATUS & ADC_STATUS_SCANACT);
|
|
*((rt_uint32_t *)args) = ADC_DataScanGet(adc->adc_device);
|
|
|
|
while (adc->adc_device->STATUS & ADC_STATUS_SINGLEACT);
|
|
*((rt_uint32_t *)args + 1) = ADC_DataSingleGet(adc->adc_device);
|
|
break;
|
|
|
|
default:
|
|
return -RT_ERROR;
|
|
}
|
|
break;
|
|
}
|
|
|
|
return RT_EOK;
|
|
}
|
|
|
|
/******************************************************************//**
|
|
* @brief
|
|
* Register ADC device
|
|
*
|
|
* @details
|
|
*
|
|
* @note
|
|
*
|
|
* @param[in] device
|
|
* Pointer to device descriptor
|
|
*
|
|
* @param[in] name
|
|
* Device name
|
|
*
|
|
* @param[in] flag
|
|
* Configuration flags
|
|
*
|
|
* @param[in] adc
|
|
* Pointer to ADC device descriptor
|
|
*
|
|
* @return
|
|
* Error code
|
|
*********************************************************************/
|
|
rt_err_t rt_hw_adc_register(
|
|
rt_device_t device,
|
|
const char *name,
|
|
rt_uint32_t flag,
|
|
struct efm32_adc_device_t *adc)
|
|
{
|
|
RT_ASSERT(device != RT_NULL);
|
|
|
|
device->type = RT_Device_Class_Char; /* fixme: should be adc type */
|
|
device->rx_indicate = RT_NULL;
|
|
device->tx_complete = RT_NULL;
|
|
device->init = rt_adc_init;
|
|
device->open = RT_NULL;
|
|
device->close = RT_NULL;
|
|
device->read = RT_NULL;
|
|
device->write = RT_NULL;
|
|
device->control = rt_adc_control;
|
|
device->user_data = adc;
|
|
|
|
/* register a character device */
|
|
return rt_device_register(device, name, flag);
|
|
}
|
|
|
|
/******************************************************************//**
|
|
* @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;
|
|
|
|
init.ovsRateSel = adcOvsRateSel4096; //TODO
|
|
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)
|
|
{
|
|
rt_kprintf("no memory for ADC driver\n");
|
|
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
|
|
}
|
|
|
|
|
|
/***************************************************************************//**
|
|
* @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.
|
|
*
|
|
* @param[in] input
|
|
* Input channel used during calibration.
|
|
*
|
|
* @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.
|
|
******************************************************************************/
|
|
rt_uint32_t efm32_adc_calibration(
|
|
ADC_TypeDef *adc,
|
|
ADC_Ref_TypeDef ref,
|
|
ADC_SingleInput_TypeDef input)
|
|
{
|
|
rt_uint32_t cal;
|
|
rt_int32_t sample;
|
|
rt_int8_t high, mid, low, tmp;
|
|
ADC_InitSingle_TypeDef singleInit = ADC_INITSINGLE_DEFAULT;
|
|
|
|
/* Init for single conversion use, measure diff 0 with selected reference. */
|
|
singleInit.reference = ref;
|
|
singleInit.input = adcSingleInpDiff0;
|
|
singleInit.acqTime = adcAcqTime32;
|
|
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 = 63;
|
|
low = -64;
|
|
|
|
/* 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);
|
|
tmp = mid < 0 ? (mid & 0x3F ^ 0x3F | 0x40) + 1 : mid;
|
|
cal |= tmp << _ADC_CAL_SINGLEOFFSET_SHIFT;
|
|
cal |= tmp << _ADC_CAL_SCANOFFSET_SHIFT;
|
|
#ifdef RT_ADC_DEBUG
|
|
rt_kprintf("adc->CAL = %x, cal = %x, tmp = %x\n", adc->CAL, cal, tmp);
|
|
#endif
|
|
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;
|
|
}
|
|
}
|
|
#ifdef RT_ADC_DEBUG
|
|
rt_kprintf("adc->CAL = %x\n", adc->CAL);
|
|
#endif
|
|
|
|
/* 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 |= (input << _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 = 127;
|
|
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;
|
|
#ifdef RT_ADC_DEBUG
|
|
rt_kprintf("adc->CAL = %x, cal = %x, mid = %x\n", adc->CAL, cal, mid);
|
|
#endif
|
|
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;
|
|
}
|
|
}
|
|
#ifdef RT_ADC_DEBUG
|
|
rt_kprintf("adc->CAL = %x\n", adc->CAL);
|
|
#endif
|
|
|
|
return adc->CAL;
|
|
}
|
|
|
|
/******************************************************************//**
|
|
* @}
|
|
*********************************************************************/
|