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/**
@page ADC_Oversampling_Init ADC example
@verbatim
******************************************************************************
* @file Examples_LL/ADC/ADC_Oversampling_Init/readme.txt
* @author MCD Application Team
* @brief Description of the ADC_Oversampling_Init example.
******************************************************************************
*
* Copyright (c) 2019-2021 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
How to use an ADC peripheral with ADC oversampling.
This example is based on the STM32WBxx ADC LL API.
The peripheral initialization done using LL unitary service functions for
optimization purposes (performance and size).
Description of ADC oversampling:
Multiple successive ADC conversions and average computation
are performed automatically, by ADC hardware, and therefore
off-load the CPU to do the equivalent task.
This feature can be used for the functions: averaging,
data rate reduction, SNR improvement, basic filtering.
This example uses 3 configurations of oversampling,
for comparison of final data to evaluate oversampling benefits.
Example configuration:
ADC is configured to convert a single channel, in single conversion mode,
from SW trigger.
ADC oversampling feature is used with 3 settings:
- ADC oversampling enabled: ratio 16, bits right shift 4.
- ADC oversampling enabled: ratio 16, no bits right shift.
- ADC oversampling disabled.
LED2 is blinking every 1 sec in case of error.
Example execution:
At each press on User push-button (SW1), with the 3 oversampling setting:
the ADC converts the selected channel, software polls for conversion completion
and stores conversion data into a variable.
When all ADC conversions are completed, LED2 is turned on.
The 3 ADC conversion data corresponding to each of the oversampling setting
are evaluated (refer to loop "while (1)" of main program):
- data validity check and SW calculation of equivalent data
on 12 bits with floating point.
- user can evaluate the expected results of oversampling:
ADC conversion data with oversampling enabled has less variation
than with oversampling disabled, calculation performed by ADC HW
is equivalent to calculation performed by SW.
For debug: variables to monitor with debugger watch window:
- "uhADCxConvertedData_OVS_ratio16_shift4": ADC group regular conversion data, oversampling ratio 16 and shift 4 (data scale: 12 bits)
- "uhADCxConvertedData_OVS_ratio16_shift0": ADC group regular conversion data, oversampling ratio 16 and shift 0 (data scale: 16 bits)
- "uhADCxConvertedData_OVS_disabled": ADC group regular conversion data, oversampling disabled (data scale corresponds to ADC resolution: 12 bits)
- "fConvertedData_OVS_EquivalentValue12bits": Calculation of oversampling raw data (from variable "uhADCxConvertedData_OVS_ratio16_shift0") to the equivalent data on 12 bits with floating point.
Connection needed:
None.
Note: Optionally, a voltage can be supplied to the analog input pin (cf pin below),
between 0V and Vdda=3.3V, to perform a ADC conversion on a determined
voltage level.
Otherwise, this pin can be let floating (in this case ADC conversion data
will be undetermined).
Other peripherals used:
1 GPIO for User push-button (SW1)
1 GPIO for LED2
1 GPIO for analog input: PA.01 (Arduino connector CN8 pin A2, Morpho connector CN7 pin 32)
@par Keywords
ADC, ADC channel, ADC oversampling, ADC group regular conversion, conversion, interrupt,
@par Directory contents
- ADC/ADC_Oversampling_Init/Inc/stm32wbxx_it.h Interrupt handlers header file
- ADC/ADC_Oversampling_Init/Inc/main.h Header for main.c module
- ADC/ADC_Oversampling_Init/Inc/stm32_assert.h Template file to include assert_failed function
- ADC/ADC_Oversampling_Init/Src/stm32wbxx_it.c Interrupt handlers
- ADC/ADC_Oversampling_Init/Src/main.c Main program
- ADC/ADC_Oversampling_Init/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55xx devices.
- This example has been tested with P-NUCLEO-WB55 board and can be
easily tailored to any other supported device and development board.
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
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