124 lines
5.8 KiB
Plaintext
124 lines
5.8 KiB
Plaintext
/**
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@page ADC_Sequencer ADC conversion example using related peripherals (GPIO, DMA), voltage input from DAC, user control by user button and LED
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file ADC/ADC_Sequencer/readme.txt
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* @author MCD Application Team
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* @brief Description of the ADC conversion example
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2016 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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How to use the ADC peripheral with a sequencer to convert several channels.
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The channels converted are, in order, one external channel and two internal
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channels (VrefInt and temperature sensors).
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Next, voltages and temperature are computed.
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WAVEFORM_VOLTAGE_GENERATION_FOR_TEST compilation switch (located in main.h) is
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available to generate a waveform voltage for the test :
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- "WAVEFORM_VOLTAGE_GENERATION_FOR_TEST" defined: waveform voltage for test is generated
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on DAC_CHANNEL_1 (output pin PA.04) by DAC peripheral.
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If ADC channel and DAC channel are selected on the same GPIO (default configuration
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in this example):
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connection is done internally in GPIO pad, user has nothing to connect.
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If ADC channel and DAC channel are selected on two different GPIO:
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user has just to connect a wire between DAC channel output and ADC input to run this example.
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- "WAVEFORM_VOLTAGE_GENERATION_FOR_TEST" not defined: no voltage is generated, user has
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to connect a voltage source to the selected ADC channel input to run this example
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Other peripherals related to ADC are used:
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Mandatory:
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- GPIO peripheral is used in analog mode to drive signal from device pin to
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ADC input.
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Optionally:
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- DMA peripheral is used to transfer ADC converted data.
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ADC settings:
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Sequencer is enabled and set to convert 3 ranks (3 channels) in discontinuous
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mode, one by one, each conversion being software-triggered.
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ADC conversion results:
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- ADC conversions results are transferred automatically by DMA, into variable
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array "aADCxConvertedValues".
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- Each entry of this array contains one of the converted data of the ADC sequencer three ranks.
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- When DMA transfer half-buffer and buffer lengths are reached, callbacks
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HAL_ADC_ConvHalfCpltCallback() and HAL_ADC_ConvCpltCallback() are called.
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- When the ADC sequence is complete (the three ADC conversions are carried out),
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the voltages and temperature are computed and stored in variables:
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uhADCChannelToDAC_mVolt, uhVrefInt_mVolt, wTemperature_DegreeCelsius.
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Board settings:
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- ADC rank 1 is configured to convert ADC_CHANNEL_4 (pin PA.04).
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If compilation switch "WAVEFORM_VOLTAGE_GENERATION_FOR_TEST" is defined, the voltage input on ADC channel comes
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from the DAC channel. This means that pins PA.04 and PA.04 must
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be connected by a wire.
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- The voltage input on ADC channel is provided from DAC channel.
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ADC and DAC channel have been chosen to have the same pad shared at device level: pin PA.04.
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==> Therefore, there is no external connection needed to run this example.
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- Voltage is increasing at each click on user button, from 0 to maximum range in 4 steps.
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Clicks on user button follow circular cycles: At clicks counter maximum value reached, counter is set back to 0.
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Channels on sequencer ranks 2 and 3 are ADC internal channels: no external connection is required.
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To observe voltage level applied on ADC channel through GPIO, connect a voltmeter on
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pin PA.04 (Arduino connector CN8 pin A2, Morpho connector CN7 pin 32).
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STM32F091RC-Nucleo RevC board's LED is be used to monitor the program execution status:
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- Normal operation: LED2 is turned-on/off with respect to ADC conversion results.
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- Turned-off if sequencer has not yet converted all ranks
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- Turned-on if sequencer has converted all ranks
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- Error: In case of error, LED2 is toggling at a frequency of 1Hz.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
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than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@par Directory contents
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- ADC/ADC_Sequencer/Inc/stm32f0xx_hal_conf.h HAL configuration file
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- ADC/ADC_Sequencer/Inc/stm32f0xx_it.h DMA interrupt handlers header file
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- ADC/ADC_Sequencer/Inc/main.h Header for main.c module
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- ADC/ADC_Sequencer/Src/stm32f0xx_it.c DMA interrupt handlers
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- ADC/ADC_Sequencer/Src/main.c Main program
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- ADC/ADC_Sequencer/Src/stm32f0xx_hal_msp.c HAL MSP file
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- ADC/ADC_Sequencer/Src/system_stm32f0xx.c STM32F0xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F0xx devices.
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- This example has been tested with STM32F091RC-Nucleo RevC board and can be
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easily tailored to any other supported device and development board.
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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*/
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