Xmega Application Note


adc_driver.h File Reference


Detailed Description

XMEGA ADC driver header file.

This file contains the function prototypes and enumerator definitions for various configuration parameters for the XMEGA ADC driver that is implemented in C.

The driver is not intended for size and/or speed critical code, since most functions are just a few lines of code, and the function call overhead would decrease code performance. The driver is intended for rapid prototyping and documentation purposes for getting started with the XMEGA ADC module.

For size and/or speed critical code, it is recommended to copy the function contents directly into your application instead of making a function call.

Application note:
AVR1300: Using the XMEGA ADC
Documentation
For comprehensive code documentation, supported compilers, compiler settings and supported devices see readme.html
Author:
Atmel Corporation: http://www.atmel.com
Support email: avr@atmel.com
Revision
Date

Copyright (c) 2008, Atmel Corporation All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of ATMEL may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Definition in file adc_driver.h.

#include "avr_compiler.h"

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Defines

#define ADC_BandgapReference_Disable(_adc)   ((_adc)->REFCTRL &= ~ADC_BANDGAP_bm)
 This macro disables the pre enabled the Bandgap Reference.
#define ADC_BandgapReference_Enable(_adc)   ((_adc)->REFCTRL |= ADC_BANDGAP_bm)
 This macro pre enables the Bandgap Reference.
#define ADC_Ch_Conversion_Complete(_adc_ch)   (((_adc_ch)->INTFLAGS & ADC_CH_CHIF_bm) != 0x00)
 This macro returns the channel conversion complete flag..
#define ADC_Ch_Conversion_Start(_adc_ch)   ((_adc_ch)->CTRL |= ADC_CH_START_bm)
 This macro starts one channel conversion.
#define ADC_Ch_InputMode_and_Gain_Config(_adc_ch, _inputMode, _gain)
 This macro configures the input mode and gain to a specific virtual channel.
#define ADC_Ch_InputMux_Config(_adc_ch, _posInput, _negInput)   ((_adc_ch)->MUXCTRL = (uint8_t) _posInput | _negInput)
 This macro configures the Positiv and negativ inputs.
#define ADC_Ch_Interrupts_Config(_adc_ch, _interruptMode, _interruptLevel)
 This macro configures the interrupt mode and level for one channel.
#define ADC_CompareValue_Set(_adc, _value)   ((_adc)->CMP = _value)
 This macro sets the value in the ADC compare register.
#define ADC_Conversions_Start(_adc, _channelMask)
 This macro starts multiple channel conversions.
#define ADC_ConvMode_and_Resolution_Config(_adc, _signedMode, _resolution)
 This macro set the conversion mode and resolution in the selected adc.
#define ADC_ConvMode_Signed   true
 Helper macro for increased readability with ADC_ConvMode_and_Resolution_Config.
#define ADC_ConvMode_Unsigned   false
 Helper macro for increased readability with ADC_ConvMode_and_Resolution_Config.
#define ADC_Disable(_adc)   ((_adc)->CTRLA = (_adc)->CTRLA & (~ADC_ENABLE_bm))
 This macro disables the selected adc.
#define ADC_DRIVER_CH_GAIN_NONE   ADC_CH_GAIN_1X_gc
 Helper macro for increased readability with ADC_Ch_InputMode_and_Gain_Config.
#define ADC_Enable(_adc)   ((_adc)->CTRLA |= ADC_ENABLE_bm)
 This macro enables the selected adc.
#define ADC_Events_Config(_adc, _eventChannels, _eventMode)
 This macro configures the event channels used and the event mode.
#define ADC_FreeRunning_Disable(_adc)   ((_adc)->CTRLB = (_adc)->CTRLB & (~ADC_FREERUN_bm))
 This macro disables the Free Running mode in the selected adc.
#define ADC_FreeRunning_Enable(_adc)   ((_adc)->CTRLB |= ADC_FREERUN_bm)
 This macro enables the Free Running mode in the selected adc.
#define ADC_Pipeline_Flush(_adc)   ((_adc)->CTRLA |= ADC_FLUSH_bm)
 This macro flushes the pipline in the selected adc.
#define ADC_Prescaler_Config(_adc, _div)   ((_adc)->PRESCALER = ((_adc)->PRESCALER & (~ADC_PRESCALER_gm)) | _div)
 This macro set the prescaler factor in the selected adc.
#define ADC_Reference_Config(_adc, _convRef)   ((_adc)->REFCTRL = ((_adc)->REFCTRL & ~(ADC_REFSEL_gm)) | _convRef)
 This macro set the conversion reference in the selected adc.
#define ADC_SweepChannels_Config(_adc, _sweepChannels)   ((_adc)->EVCTRL = ((_adc)->EVCTRL & (~ADC_SWEEP_gm)) | _sweepChannels)
 This macro sets the sweep channel settings.
#define ADC_TempReference_Disable(_adc)   ((_adc)->REFCTRL = (_adc)->REFCTRL & (~ADC_TEMPREF_bm))
 This macro disables the temperature reference.
#define ADC_TempReference_Enable(_adc)   ((_adc)->REFCTRL |= ADC_TEMPREF_bm)
 This macro makes sure that the temperature reference circuitry is enabled.
#define COMMON_MODE_CYCLES   16
Deprecated functions
Deprecated functions: Compatibility with previous application note version. These functions will be removed in later releases of the driver

#define ADC_CalibrationValues_Set(_adc)   ADC_CalibrationValues_Load(_adc)
#define ADC_Referance_Config(_adc, _convRef)   ADC_Reference_Config(_adc, _convRef)
GCC compatibility macros
Offset addresses for production signature row on which is not in current GCC header files

#define ADCACAL0_offset   0x20
#define ADCACAL1_offset   0x21
#define ADCBCAL0_offset   0x24
#define ADCBCAL1_offset   0x25

Functions

void ADC_CalibrationValues_Load (ADC_t *adc)
 This function get the calibration data from the production calibration.
int8_t ADC_Offset_Get_Signed (ADC_t *adc, ADC_CH_t *ch, bool oversampling)
 This function gets the offset of the ADC when it is configured in signed mode.
uint8_t ADC_Offset_Get_Unsigned (ADC_t *adc, ADC_CH_t *ch, bool oversampling)
 This function gets the offset of the ADC when it is configured in unsigned mode.
uint8_t ADC_ResultCh_GetHighByte (ADC_CH_t *adc_ch)
 This function clears the interrupt flag and returns the high byte of the coversion result.
uint8_t ADC_ResultCh_GetLowByte (ADC_CH_t *adc_ch)
 This function clears the interrupt flag and returns the low byte of the coversion result.
uint16_t ADC_ResultCh_GetWord (ADC_CH_t *adc_ch)
 This function clears the interrupt flag and returns the coversion result without compensating for offset.
int16_t ADC_ResultCh_GetWord_Signed (ADC_CH_t *adc_ch, int8_t offset)
 This function clears the interrupt flag and returns the signed coversion result.
uint16_t ADC_ResultCh_GetWord_Unsigned (ADC_CH_t *adc_ch, uint8_t offset)
 This function clears the interrupt flag and returns the unsigned coversion result.
void ADC_Wait_32MHz (ADC_t *adc)
 This function waits until the adc common mode is settled.
void ADC_Wait_8MHz (ADC_t *adc)
 This function waits until the adc common mode is settled.
uint8_t SP_ReadCalibrationByte (uint8_t index)


Define Documentation

#define ADC_BandgapReference_Disable ( _adc   )     ((_adc)->REFCTRL &= ~ADC_BANDGAP_bm)

This macro disables the pre enabled the Bandgap Reference.

Parameters:
_adc Pointer to ADC module register section.

Definition at line 319 of file adc_driver.h.

#define ADC_BandgapReference_Enable ( _adc   )     ((_adc)->REFCTRL |= ADC_BANDGAP_bm)

This macro pre enables the Bandgap Reference.

Note:
If the ADC is enabled the Bandgap Reference is automaticly enabled.
Parameters:
_adc Pointer to ADC module register section.

Definition at line 312 of file adc_driver.h.

#define ADC_CalibrationValues_Set ( _adc   )     ADC_CalibrationValues_Load(_adc)

Definition at line 364 of file adc_driver.h.

#define ADC_Ch_Conversion_Complete ( _adc_ch   )     (((_adc_ch)->INTFLAGS & ADC_CH_CHIF_bm) != 0x00)

This macro returns the channel conversion complete flag..

Parameters:
_adc_ch Pointer to ADC Channel register section.
Returns:
value of channels conversion complete flag.

Definition at line 243 of file adc_driver.h.

Referenced by ADC_Offset_Get_Signed(), ADC_Offset_Get_Unsigned(), and main().

#define ADC_Ch_Conversion_Start ( _adc_ch   )     ((_adc_ch)->CTRL |= ADC_CH_START_bm)

This macro starts one channel conversion.

Use the ADC_GetWordResultCh or ADC_GetByteResultCh functions to retrieve the conversion result. This macro is not to be used when the ADC is running in free-running mode.

Parameters:
_adc_ch Pointer to ADC Channel module register section.

Definition at line 286 of file adc_driver.h.

Referenced by ADC_Offset_Get_Signed(), and ADC_Offset_Get_Unsigned().

#define ADC_Ch_InputMode_and_Gain_Config ( _adc_ch,
_inputMode,
_gain   ) 

Value:

(_adc_ch)->CTRL = ((_adc_ch)->CTRL &                                   \
                          (~(ADC_CH_INPUTMODE_gm|ADC_CH_GAINFAC_gm))) |        \
                          ((uint8_t) _inputMode|_gain)
This macro configures the input mode and gain to a specific virtual channel.

Parameters:
_adc_ch Pointer to ADC channel register section.
_inputMode Input mode for this channel, differential, single-ended, gain etc. Use ADC_CH_INPUTMODE_t type.
_gain The preamplifiers gain value. Use ADC_CH_GAINFAC_t type.

Definition at line 210 of file adc_driver.h.

Referenced by main().

#define ADC_Ch_InputMux_Config ( _adc_ch,
_posInput,
_negInput   )     ((_adc_ch)->MUXCTRL = (uint8_t) _posInput | _negInput)

This macro configures the Positiv and negativ inputs.

Parameters:
_adc_ch Which ADC channel to configure.
_posInput Which pin (or internal signal) to connect to positive ADC input. Use ADC_CH_MUXPOS_enum type.
_negInput Which pin to connect to negative ADC input. Use ADC_CH_MUXNEG_t type.
Note:
The negative input is connected to GND for single-ended and internal input modes.

Definition at line 233 of file adc_driver.h.

Referenced by main().

#define ADC_Ch_Interrupts_Config ( _adc_ch,
_interruptMode,
_interruptLevel   ) 

Value:

(_adc_ch)->INTCTRL = (((_adc_ch)->INTCTRL &                            \
                              (~(ADC_CH_INTMODE_gm | ADC_CH_INTLVL_gm))) |     \
                              ((uint8_t) _interruptMode | _interruptLevel))
This macro configures the interrupt mode and level for one channel.

The interrupt mode affects the interrupt flag for the virtual channel, and thus also affects code that polls this flag instead of using interrupts.

Note:
When using the result comparator function, the compare value must be set using the ADC_SetCompareValue function.
Parameters:
_adc_ch Pointer to ADC channel register section.
_interruptMode Interrupt mode, flag on complete or above/below compare value. Use ADC_CH_INTMODE_t type.
_interruptLevel Disable or set low/med/high priority for this virtual channel. Use ADC_CH_INTLVL_t type.

Definition at line 195 of file adc_driver.h.

Referenced by ISR(), and main().

#define ADC_CompareValue_Set ( _adc,
_value   )     ((_adc)->CMP = _value)

This macro sets the value in the ADC compare register.

The value in the ADC compare register is used by the result comparator for channels that are configured to notify when result is above or below this value. Even if the ADC compare value register is always left adjusted, the input to this function is adjusted according to the result presentation setup for the ADC. This means that the value will be right adjusted unless the "12-bit left adjust" result mode is selected with ADC_ConvMode_and_Resolution_Config.

Parameters:
_adc Pointer to ADC module register section.
_value 12-bit value used by the result comparator. Use uint16_t type.

Definition at line 260 of file adc_driver.h.

#define ADC_Conversions_Start ( _adc,
_channelMask   ) 

Value:

(_adc)->CTRLA |= _channelMask &                                   \
                      (ADC_CH0START_bm | ADC_CH1START_bm |                \
                       ADC_CH2START_bm | ADC_CH3START_bm)
This macro starts multiple channel conversions.

This macro starts a conversion for the channels selected by the channel mask parameter. Use the bit mask defines for each channel and combine them into one byte using bitwise OR. The available masks are ADC_CH0START_bm, ADC_CH1START_bm, ADC_CH2START_bm and ADC_CH3START_bm.

Parameters:
_adc Pointer to ADC module register section.
_channelMask A bitmask selecting which channels to check.

Definition at line 300 of file adc_driver.h.

#define ADC_ConvMode_and_Resolution_Config ( _adc,
_signedMode,
_resolution   ) 

Value:

((_adc)->CTRLB = ((_adc)->CTRLB & (~(ADC_RESOLUTION_gm|ADC_CONMODE_bm)))|  \
                (_resolution| ( _signedMode? ADC_CONMODE_bm : 0)))
This macro set the conversion mode and resolution in the selected adc.

This macro configures the conversion mode to signed or unsigned and set the resolution in and the way the results are put in the result registers.

Parameters:
_adc Pointer to ADC module register section
_signedMode Selects conversion mode: signed (true) or unsigned (false). USE bool type.
_resolution Resolution and presentation selection. Use ADC_RESOLUTION_t type.

Definition at line 111 of file adc_driver.h.

Referenced by main().

#define ADC_ConvMode_Signed   true

Helper macro for increased readability with ADC_ConvMode_and_Resolution_Config.

See also:
ADC_ConvMode_and_Resolution_Config

Definition at line 119 of file adc_driver.h.

Referenced by main().

#define ADC_ConvMode_Unsigned   false

Helper macro for increased readability with ADC_ConvMode_and_Resolution_Config.

See also:
ADC_ConvMode_and_Resolution_Config

Definition at line 125 of file adc_driver.h.

#define ADC_Disable ( _adc   )     ((_adc)->CTRLA = (_adc)->CTRLA & (~ADC_ENABLE_bm))

This macro disables the selected adc.

Parameters:
_adc Pointer to ADC module register section

Definition at line 89 of file adc_driver.h.

Referenced by ISR(), and main().

#define ADC_DRIVER_CH_GAIN_NONE   ADC_CH_GAIN_1X_gc

Helper macro for increased readability with ADC_Ch_InputMode_and_Gain_Config.

See also:
ADC_Ch_InputMode_and_Gain_Config

Definition at line 220 of file adc_driver.h.

Referenced by main().

#define ADC_Enable ( _adc   )     ((_adc)->CTRLA |= ADC_ENABLE_bm)

This macro enables the selected adc.

Before the ADC is enabled the first time the function ADC_CalibrationValues_Set should be used to reduce the gain error in the ADC.

Note:
After the ADC is enabled the commen mode voltage in the ADC is ready after 12 ADC clock cycels. Do one dummy conversion or wait the required number of clock cycles to reasure correct conversion.
Parameters:
_adc Pointer to ADC module register section.

Definition at line 83 of file adc_driver.h.

Referenced by main().

#define ADC_Events_Config ( _adc,
_eventChannels,
_eventMode   ) 

Value:

\                                                                           \
        (_adc)->EVCTRL = ((_adc)->EVCTRL & (~(ADC_EVSEL_gm | ADC_EVACT_gm))) | \
                         ((uint8_t) _eventChannels | _eventMode)
This macro configures the event channels used and the event mode.

This macro configures the way events are used to trigger conversions for the virtual channels. Use the eventChannels parameter to select which event channel to associate with virtual channel 0 or to trigger a conversion sweep, depending on the selected eventMode parameter.

Parameters:
_adc Pointer to ADC module register section.
_eventChannels The first event channel to be used for triggering. Use ADC_EVSEL_t type.
_eventMode Select event trigger mode. Use ADC_EVACT_t type.

Definition at line 176 of file adc_driver.h.

#define ADC_FreeRunning_Disable ( _adc   )     ((_adc)->CTRLB = (_adc)->CTRLB & (~ADC_FREERUN_bm))

This macro disables the Free Running mode in the selected adc.

Parameters:
_adc Pointer to ADC module register section.

Definition at line 274 of file adc_driver.h.

Referenced by ISR(), and main().

#define ADC_FreeRunning_Enable ( _adc   )     ((_adc)->CTRLB |= ADC_FREERUN_bm)

This macro enables the Free Running mode in the selected adc.

Parameters:
_adc Pointer to ADC module register section.

Definition at line 267 of file adc_driver.h.

Referenced by main().

#define ADC_Pipeline_Flush ( _adc   )     ((_adc)->CTRLA |= ADC_FLUSH_bm)

This macro flushes the pipline in the selected adc.

Parameters:
_adc Pointer to ADC module register section

Definition at line 95 of file adc_driver.h.

#define ADC_Prescaler_Config ( _adc,
_div   )     ((_adc)->PRESCALER = ((_adc)->PRESCALER & (~ADC_PRESCALER_gm)) | _div)

This macro set the prescaler factor in the selected adc.

This macro configures the division factor between the XMEGA IO-clock and the ADC clock. Given a certain IO-clock, the prescaler must be configured so the the ADC clock is within recommended limits. A faster IO-clock required higher division factors.

Note:
The maximum ADC sample rate is always one fourth of the IO clock.
Parameters:
_adc Pointer to ADC module register section.
_div ADC prescaler division factor setting. Use ADC_PRESCALER_t type

Definition at line 140 of file adc_driver.h.

Referenced by main().

#define ADC_Referance_Config ( _adc,
_convRef   )     ADC_Reference_Config(_adc, _convRef)

Definition at line 363 of file adc_driver.h.

#define ADC_Reference_Config ( _adc,
_convRef   )     ((_adc)->REFCTRL = ((_adc)->REFCTRL & ~(ADC_REFSEL_gm)) | _convRef)

This macro set the conversion reference in the selected adc.

Parameters:
_adc Pointer to ADC module register section.
_convRef Selects reference voltage for all conversions. Use ADC_REFSEL_t type.

Definition at line 150 of file adc_driver.h.

Referenced by main().

#define ADC_SweepChannels_Config ( _adc,
_sweepChannels   )     ((_adc)->EVCTRL = ((_adc)->EVCTRL & (~ADC_SWEEP_gm)) | _sweepChannels)

This macro sets the sweep channel settings.

Parameters:
_adc Pointer to ADC module register section.
_sweepChannels Sweep channel selection. Use ADC_SWEEP_t type

Definition at line 159 of file adc_driver.h.

Referenced by main().

#define ADC_TempReference_Disable ( _adc   )     ((_adc)->REFCTRL = (_adc)->REFCTRL & (~ADC_TEMPREF_bm))

This macro disables the temperature reference.

Parameters:
_adc Pointer to ADC module register section.

Definition at line 335 of file adc_driver.h.

#define ADC_TempReference_Enable ( _adc   )     ((_adc)->REFCTRL |= ADC_TEMPREF_bm)

This macro makes sure that the temperature reference circuitry is enabled.

Note:
Enabling the temperature reference automatically enables the bandgap reference.
Parameters:
_adc Pointer to ADC module register section.

Definition at line 328 of file adc_driver.h.

#define ADCACAL0_offset   0x20

Definition at line 375 of file adc_driver.h.

Referenced by ADC_CalibrationValues_Load().

#define ADCACAL1_offset   0x21

Definition at line 376 of file adc_driver.h.

Referenced by ADC_CalibrationValues_Load().

#define ADCBCAL0_offset   0x24

Definition at line 377 of file adc_driver.h.

Referenced by ADC_CalibrationValues_Load().

#define ADCBCAL1_offset   0x25

Definition at line 378 of file adc_driver.h.

#define COMMON_MODE_CYCLES   16

Definition at line 66 of file adc_driver.h.

Referenced by ADC_Wait_32MHz(), and ADC_Wait_8MHz().


Function Documentation

void ADC_CalibrationValues_Load ( ADC_t *  adc  ) 

This function get the calibration data from the production calibration.

The calibration data is loaded from flash and stored in the calibration register. The calibration data reduces the non-linearity error in the adc.

Parameters:
adc Pointer to ADC module register section.

Definition at line 77 of file adc_driver.c.

References ADCACAL0_offset, ADCACAL1_offset, ADCBCAL0_offset, and SP_ReadCalibrationByte().

00078 {
00079         if(&ADCA == adc){
00080                  /* Get ADCACAL0 from production signature . */
00081                 adc->CALL = SP_ReadCalibrationByte( PROD_SIGNATURES_START + ADCACAL0_offset );
00082                 adc->CALH = SP_ReadCalibrationByte( PROD_SIGNATURES_START + ADCACAL1_offset );
00083         }else {
00084                 /* Get ADCBCAL0 from production signature  */
00085                 adc->CALL = SP_ReadCalibrationByte( PROD_SIGNATURES_START + ADCBCAL0_offset );
00086                 adc->CALH = SP_ReadCalibrationByte( PROD_SIGNATURES_START + ADCACAL1_offset );
00087         }
00088 }

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int8_t ADC_Offset_Get_Signed ( ADC_t *  adc,
ADC_CH_t *  ch,
bool  oversampling 
)

This function gets the offset of the ADC when it is configured in signed mode.

This function does one or several measurements to determine the offset of the ADC.

Note:
The ADC must be configured and enabled before this function is run.

This function only return the low byte of the 12-bit convertion, because the offset should never be more than +-8 LSB off.

Parameters:
adc Pointer to the ADC to calculate offset from.
ch Pointer to the ADC channel to measure on.
oversampling false for one measurement. true for averaging several measurements.
Returns:
Offset on the selected ADC

Definition at line 318 of file adc_driver.c.

References ADC_Ch_Conversion_Complete, ADC_Ch_Conversion_Start, ADC_ResultCh_GetWord_Signed(), and offset.

00319 {
00320     if (oversampling)
00321     {
00322       int16_t offset=0;
00323       for (int i=0; i<4; i++)
00324       {
00325         /* Do one conversion to find offset. */
00326         ADC_Ch_Conversion_Start(ch);
00327     
00328         do{
00329         }while(!ADC_Ch_Conversion_Complete(ch));
00330         offset += ADC_ResultCh_GetWord_Signed(ch, 0x00);
00331       }
00332       return ((int8_t)(offset/4));
00333     }
00334     else
00335     {        
00336       int8_t offset=0;
00337       
00338       /* Do one conversion to find offset. */
00339       ADC_Ch_Conversion_Start(ch);
00340   
00341       do{
00342       }while(!ADC_Ch_Conversion_Complete(ch));
00343       offset = (uint8_t)ADC_ResultCh_GetWord_Signed(ch, 0x00);
00344       
00345       return offset;
00346     }
00347 }

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uint8_t ADC_Offset_Get_Unsigned ( ADC_t *  adc,
ADC_CH_t *  ch,
bool  oversampling 
)

This function gets the offset of the ADC when it is configured in unsigned mode.

This function does one or several measurements to determine the offset of the ADC.

Note:
The ADC must be configured and enabled before this function is run.

This function only return the low byte of the 12-bit convertion, because the offset should never be more than +-8 LSB off.

Parameters:
adc Pointer to the ADC to calculate offset from.
ch Pointer to the ADC channel to measure on.
oversampling false for one measurement. true for averaging several measurements.
Returns:
Offset on the selected ADC

Definition at line 271 of file adc_driver.c.

References ADC_Ch_Conversion_Complete, ADC_Ch_Conversion_Start, ADC_ResultCh_GetWord(), ADC_ResultCh_GetWord_Unsigned(), and offset.

00272 {
00273     if (oversampling)
00274     {
00275       uint16_t offset=0;
00276       for (int i=0; i<4; i++)
00277       {
00278         /* Do one conversion to find offset. */
00279         ADC_Ch_Conversion_Start(ch);
00280     
00281         do{
00282         }while(!ADC_Ch_Conversion_Complete(ch));
00283         offset += ADC_ResultCh_GetWord_Unsigned(ch, 0x00);
00284       }
00285       return ((uint8_t)(offset>>2));
00286     }
00287     else
00288     {        
00289       uint8_t offset=0;
00290       
00291       /* Do one conversion to find offset. */
00292       ADC_Ch_Conversion_Start(ch);
00293   
00294       do{
00295       }while(!ADC_Ch_Conversion_Complete(ch));
00296       offset = (uint8_t)ADC_ResultCh_GetWord(ch);
00297       
00298       return offset;
00299     }
00300 }

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uint8_t ADC_ResultCh_GetHighByte ( ADC_CH_t *  adc_ch  ) 

This function clears the interrupt flag and returns the high byte of the coversion result.

This funtion should be used together with the ADC_ResultCh_ConversionComplete. When the conversion result is ready this function reads out the result.

Note:
If this function is used with 12-bit right adjusted results, it returns the 8 LSB only. Offset is not compensated.
Parameters:
adc_ch Pointer to ADC channel register section.
Returns:
High byte of conversion result.

Definition at line 186 of file adc_driver.c.

00187 {
00188         /* Clear interrupt flag.*/
00189         adc_ch->INTFLAGS = ADC_CH_CHIF_bm;
00190 
00191         /* Return low byte result register contents.*/
00192         return adc_ch->RESH;
00193 }

uint8_t ADC_ResultCh_GetLowByte ( ADC_CH_t *  adc_ch  ) 

This function clears the interrupt flag and returns the low byte of the coversion result.

This funtion should be used together with the ADC_Ch_Conversion_Complete. When the conversion result is ready this funciton reads out the result.

Note:
If this function is used with 12-bit right adjusted results, it returns the 8 LSB only. Offset is not compensated.
Parameters:
adc_ch Pointer to ADC channel register section.
Returns:
Low byte of conversion result.

Definition at line 166 of file adc_driver.c.

00167 {
00168         /* Clear interrupt flag.*/
00169         adc_ch->INTFLAGS = ADC_CH_CHIF_bm;
00170         /* Return result register contents*/
00171         return adc_ch->RESL;
00172 }

uint16_t ADC_ResultCh_GetWord ( ADC_CH_t *  adc_ch  ) 

This function clears the interrupt flag and returns the coversion result without compensating for offset.

This function should be used together with the ADC_Ch_Conversion_Complete. When the conversion result is ready this funciton reads out the result.

Parameters:
adc_ch Pointer to ADC channel register section.
Returns:
Signed conversion result.

Definition at line 144 of file adc_driver.c.

00145 {
00146         /* Clear interrupt flag.*/
00147         adc_ch->INTFLAGS = ADC_CH_CHIF_bm;
00148 
00149         /* Return result register contents*/
00150         return adc_ch->RES;;
00151 }

int16_t ADC_ResultCh_GetWord_Signed ( ADC_CH_t *  adc_ch,
int8_t  signedOffset 
)

This function clears the interrupt flag and returns the signed coversion result.

This function should be used together with the ADC_Ch_Conversion_Complete. When the conversion result is ready this funciton reads out the result.

Parameters:
adc_ch Pointer to ADC channel register section.
signedOffset Offset value to subtract.
Returns:
The signed Conversion result with the offset substracted.

Definition at line 123 of file adc_driver.c.

00124 {
00125         int16_t answer;
00126 
00127         /* Clear interrupt flag.*/
00128         adc_ch->INTFLAGS = ADC_CH_CHIF_bm;
00129 
00130         /* Return result register contents*/
00131         answer = adc_ch->RES - signedOffset;
00132 
00133         return answer;
00134 }

uint16_t ADC_ResultCh_GetWord_Unsigned ( ADC_CH_t *  adc_ch,
uint8_t  offset 
)

This function clears the interrupt flag and returns the unsigned coversion result.

This function should be used together with the ADC_Ch_Conversion_Complete. When the conversion result is ready this funciton reads out the result.

Parameters:
adc_ch Pointer to ADC channel register section.
offset Unsigned offset value to subtract.
Returns:
The unsigned Conversion result with the offset substracted.

Definition at line 100 of file adc_driver.c.

00101 {
00102         uint16_t answer;
00103 
00104         /* Clear interrupt flag.*/
00105         adc_ch->INTFLAGS = ADC_CH_CHIF_bm;
00106 
00107         /* Return result register contents*/
00108         answer = adc_ch->RES - offset;
00109 
00110         return answer;
00111 }

void ADC_Wait_32MHz ( ADC_t *  adc  ) 

This function waits until the adc common mode is settled.

After the ADC clock has been turned on, the common mode voltage in the ADC need some time to settle. The time it takes equals one dummy conversion. Instead of doing a dummy conversion this function waits until the common mode is settled.

Note:
The function sets the prescaler to the minimum value possible when the clock speed is larger than 8 MHz to minimize the time it takes the common mode to settle.

The ADC clock is turned off every time the ADC i disabled or the device goes into sleep (not Idle sleep mode).

Parameters:
adc Pointer to ADC module register section.

Definition at line 240 of file adc_driver.c.

References COMMON_MODE_CYCLES.

00241 {
00242         /* Store old prescaler value. */
00243         uint8_t prescaler_val = adc->PRESCALER;
00244 
00245         /* Set prescaler value to minimum value. */
00246         adc->PRESCALER = ADC_PRESCALER_DIV8_gc;
00247 
00248         /* wait 8*COMMON_MODE_CYCLES for common mode to settle*/
00249         delay_us(8*COMMON_MODE_CYCLES);
00250 
00251         /* Set prescaler to old value*/
00252         adc->PRESCALER = prescaler_val;
00253 }

void ADC_Wait_8MHz ( ADC_t *  adc  ) 

This function waits until the adc common mode is settled.

After the ADC clock has been turned on, the common mode voltage in the ADC need some time to settle. The time it takes equals one dummy conversion. Instead of doing a dummy conversion this function waits until the common mode is settled.

Note:
The function sets the prescaler to the minimum value to minimize the time it takes the common mode to settle. If the clock speed is higher than 8 MHz use the ADC_wait_32MHz function.
Parameters:
adc Pointer to ADC module register section.

Definition at line 208 of file adc_driver.c.

References COMMON_MODE_CYCLES.

00209 {
00210         /* Store old prescaler value. */
00211         uint8_t prescaler_val = adc->PRESCALER;
00212 
00213         /* Set prescaler value to minimum value. */
00214         adc->PRESCALER = ADC_PRESCALER_DIV4_gc;
00215 
00216         /* Wait 4*COMMON_MODE_CYCLES for common mode to settle. */
00217         delay_us(4*COMMON_MODE_CYCLES);
00218 
00219         /* Set prescaler to old value*/
00220         adc->PRESCALER = prescaler_val;
00221 }

uint8_t SP_ReadCalibrationByte ( uint8_t  index  ) 

Referenced by ADC_CalibrationValues_Load().

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