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RTEMS 6.1-rc6
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RTEMS 6.1-rc6
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DAC HAL module driver. This file provides firmware functions to manage the following functionalities of the Digital to Analog Converter (DAC) peripheral: More...
#include "stm32h7xx_hal.h"DAC HAL module driver. This file provides firmware functions to manage the following functionalities of the Digital to Analog Converter (DAC) peripheral:
Copyright (c) 2017 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.
==============================================================================
##### DAC Peripheral features #####
==============================================================================
[..]
*** DAC Channels ***
====================
[..]
STM32H7 devices integrate two 12-bit Digital Analog Converters
The 2 converters (i.e. channel1 & channel2)
can be used independently or simultaneously (dual mode):
(#) DAC channel1 with DAC_OUT1 (PA4) as output or connected to on-chip
peripherals (ex. OPAMPs, comparators).
(#) DAC channel2 with DAC_OUT2 (PA5) as output or connected to on-chip
peripherals (ex. OPAMPs, comparators).
*** DAC Triggers ***
====================
[..]
Digital to Analog conversion can be non-triggered using DAC_TRIGGER_NONE
and DAC_OUT1/DAC_OUT2 is available once writing to DHRx register.
[..]
Digital to Analog conversion can be triggered by:
(#) External event: EXTI Line 9 (any GPIOx_PIN_9) using DAC_TRIGGER_EXT_IT9.
The used pin (GPIOx_PIN_9) must be configured in input mode.
(#) Timers TRGO: TIM1, TIM2, TIM4, TIM5, TIM6, TIM7, TIM8, TIM15, TIM23 and TIM24
(DAC_TRIGGER_T1_TRGO, DAC_TRIGGER_T2_TRGO...)
(#) Low Power Timers TRGO: LPTIM1, LPTIM2 and LPTIM3
(DAC_TRIGGER_LPTIM1_OUT, DAC_TRIGGER_LPTIM2_OUT)
(#) High Resolution Timer TRGO: HRTIM1
(DAC_TRIGGER_HR1_TRGO1, DAC_TRIGGER_HR1_TRGO2)
(#) Software using DAC_TRIGGER_SOFTWARE
*** DAC Buffer mode feature ***
===============================
[..]
Each DAC channel integrates an output buffer that can be used to
reduce the output impedance, and to drive external loads directly
without having to add an external operational amplifier.
To enable, the output buffer use
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
[..]
(@) Refer to the device datasheet for more details about output
impedance value with and without output buffer.
*** GPIO configurations guidelines ***
=====================
[..]
When a DAC channel is used (ex channel1 on PA4) and the other is not
(ex channel2 on PA5 is configured in Analog and disabled).
Channel1 may disturb channel2 as coupling effect.
Note that there is no coupling on channel2 as soon as channel2 is turned on.
Coupling on adjacent channel could be avoided as follows:
when unused PA5 is configured as INPUT PULL-UP or DOWN.
PA5 is configured in ANALOG just before it is turned on.
*** DAC Sample and Hold feature ***
========================
[..]
For each converter, 2 modes are supported: normal mode and
"sample and hold" mode (i.e. low power mode).
In the sample and hold mode, the DAC core converts data, then holds the
converted voltage on a capacitor. When not converting, the DAC cores and
buffer are completely turned off between samples and the DAC output is
tri-stated, therefore reducing the overall power consumption. A new
stabilization period is needed before each new conversion.
The sample and hold allow setting internal or external voltage @
low power consumption cost (output value can be at any given rate either
by CPU or DMA).
The Sample and hold block and registers uses either LSI & run in
several power modes: run mode, sleep mode, low power run, low power sleep
mode & stop1 mode.
Low power stop1 mode allows only static conversion.
To enable Sample and Hold mode
Enable LSI using HAL_RCC_OscConfig with RCC_OSCILLATORTYPE_LSI &
RCC_LSI_ON parameters.
Use DAC_InitStructure.DAC_SampleAndHold = DAC_SAMPLEANDHOLD_ENABLE;
& DAC_ChannelConfTypeDef.DAC_SampleAndHoldConfig.DAC_SampleTime,
DAC_HoldTime & DAC_RefreshTime;
*** DAC calibration feature ***
===================================
[..]
(#) The 2 converters (channel1 & channel2) provide calibration capabilities.
(++) Calibration aims at correcting some offset of output buffer.
(++) The DAC uses either factory calibration settings OR user defined
calibration (trimming) settings (i.e. trimming mode).
(++) The user defined settings can be figured out using self calibration
handled by HAL_DACEx_SelfCalibrate.
(++) HAL_DACEx_SelfCalibrate:
(+++) Runs automatically the calibration.
(+++) Enables the user trimming mode
(+++) Updates a structure with trimming values with fresh calibration
results.
The user may store the calibration results for larger
(ex monitoring the trimming as a function of temperature
for instance)
*** DAC wave generation feature ***
===================================
[..]
Both DAC channels can be used to generate
(#) Noise wave
(#) Triangle wave
*** DAC data format ***
=======================
[..]
The DAC data format can be:
(#) 8-bit right alignment using DAC_ALIGN_8B_R
(#) 12-bit left alignment using DAC_ALIGN_12B_L
(#) 12-bit right alignment using DAC_ALIGN_12B_R
*** DAC data value to voltage correspondence ***
================================================
[..]
The analog output voltage on each DAC channel pin is determined
by the following equation:
[..]
DAC_OUTx = VREF+ * DOR / 4095
(+) with DOR is the Data Output Register
[..]
VREF+ is the input voltage reference (refer to the device datasheet)
[..]
e.g. To set DAC_OUT1 to 0.7V, use
(+) Assuming that VREF+ = 3.3V, DAC_OUT1 = (3.3 * 868) / 4095 = 0.7V
*** DMA requests ***
=====================
[..]
A DMA request can be generated when an external trigger (but not a software trigger)
occurs if DMA requests are enabled using HAL_DAC_Start_DMA().
DMA requests are mapped as following:
(#) DAC channel1: mapped on DMA_REQUEST_DAC1_CH1
(#) DAC channel2: mapped on DMA_REQUEST_DAC1_CH2
[..]
(@) For Dual mode and specific signal (Triangle and noise) generation please
refer to Extended Features Driver description
##### How to use this driver #####
==============================================================================
[..]
(+) DAC APB clock must be enabled to get write access to DAC
registers using HAL_DAC_Init()
(+) Configure DAC_OUTx (DAC_OUT1: PA4, DAC_OUT2: PA5) in analog mode.
(+) Configure the DAC channel using HAL_DAC_ConfigChannel() function.
(+) Enable the DAC channel using HAL_DAC_Start() or HAL_DAC_Start_DMA() functions.
*** Calibration mode IO operation ***
======================================
[..]
(+) Retrieve the factory trimming (calibration settings) using HAL_DACEx_GetTrimOffset()
(+) Run the calibration using HAL_DACEx_SelfCalibrate()
(+) Update the trimming while DAC running using HAL_DACEx_SetUserTrimming()
*** Polling mode IO operation ***
=================================
[..]
(+) Start the DAC peripheral using HAL_DAC_Start()
(+) To read the DAC last data output value, use the HAL_DAC_GetValue() function.
(+) Stop the DAC peripheral using HAL_DAC_Stop()
*** DMA mode IO operation ***
==============================
[..]
(+) Start the DAC peripheral using HAL_DAC_Start_DMA(), at this stage the user specify the length
of data to be transferred at each end of conversion
First issued trigger will start the conversion of the value previously set by HAL_DAC_SetValue().
(+) At the middle of data transfer HAL_DAC_ConvHalfCpltCallbackCh1() or HAL_DACEx_ConvHalfCpltCallbackCh2()
function is executed and user can add his own code by customization of function pointer
HAL_DAC_ConvHalfCpltCallbackCh1() or HAL_DACEx_ConvHalfCpltCallbackCh2()
(+) At The end of data transfer HAL_DAC_ConvCpltCallbackCh1() or HAL_DACEx_ConvHalfCpltCallbackCh2()
function is executed and user can add his own code by customization of function pointer
HAL_DAC_ConvCpltCallbackCh1() or HAL_DACEx_ConvHalfCpltCallbackCh2()
(+) In case of transfer Error, HAL_DAC_ErrorCallbackCh1() function is executed and user can
add his own code by customization of function pointer HAL_DAC_ErrorCallbackCh1
(+) In case of DMA underrun, DAC interruption triggers and execute internal function HAL_DAC_IRQHandler.
HAL_DAC_DMAUnderrunCallbackCh1() or HAL_DACEx_DMAUnderrunCallbackCh2()
function is executed and user can add his own code by customization of function pointer
HAL_DAC_DMAUnderrunCallbackCh1() or HAL_DACEx_DMAUnderrunCallbackCh2() and
add his own code by customization of function pointer HAL_DAC_ErrorCallbackCh1()
(+) Stop the DAC peripheral using HAL_DAC_Stop_DMA()
*** Callback registration ***
=============================================
[..]
The compilation define USE_HAL_DAC_REGISTER_CALLBACKS when set to 1
allows the user to configure dynamically the driver callbacks.
Use Functions HAL_DAC_RegisterCallback() to register a user callback,
it allows to register following callbacks:
(+) ConvCpltCallbackCh1 : callback when a half transfer is completed on Ch1.
(+) ConvHalfCpltCallbackCh1 : callback when a transfer is completed on Ch1.
(+) ErrorCallbackCh1 : callback when an error occurs on Ch1.
(+) DMAUnderrunCallbackCh1 : callback when an underrun error occurs on Ch1.
(+) ConvCpltCallbackCh2 : callback when a half transfer is completed on Ch2.
(+) ConvHalfCpltCallbackCh2 : callback when a transfer is completed on Ch2.
(+) ErrorCallbackCh2 : callback when an error occurs on Ch2.
(+) DMAUnderrunCallbackCh2 : callback when an underrun error occurs on Ch2.
(+) MspInitCallback : DAC MspInit.
(+) MspDeInitCallback : DAC MspdeInit.
This function takes as parameters the HAL peripheral handle, the Callback ID
and a pointer to the user callback function.
Use function HAL_DAC_UnRegisterCallback() to reset a callback to the default
weak (overridden) function. It allows to reset following callbacks:
(+) ConvCpltCallbackCh1 : callback when a half transfer is completed on Ch1.
(+) ConvHalfCpltCallbackCh1 : callback when a transfer is completed on Ch1.
(+) ErrorCallbackCh1 : callback when an error occurs on Ch1.
(+) DMAUnderrunCallbackCh1 : callback when an underrun error occurs on Ch1.
(+) ConvCpltCallbackCh2 : callback when a half transfer is completed on Ch2.
(+) ConvHalfCpltCallbackCh2 : callback when a transfer is completed on Ch2.
(+) ErrorCallbackCh2 : callback when an error occurs on Ch2.
(+) DMAUnderrunCallbackCh2 : callback when an underrun error occurs on Ch2.
(+) MspInitCallback : DAC MspInit.
(+) MspDeInitCallback : DAC MspdeInit.
(+) All Callbacks
This function) takes as parameters the HAL peripheral handle and the Callback ID.
By default, after the HAL_DAC_Init and if the state is HAL_DAC_STATE_RESET
all callbacks are reset to the corresponding legacy weak (overridden) functions.
Exception done for MspInit and MspDeInit callbacks that are respectively
reset to the legacy weak (overridden) functions in the HAL_DAC_Init
and HAL_DAC_DeInit only when these callbacks are null (not registered beforehand).
If not, MspInit or MspDeInit are not null, the HAL_DAC_Init and HAL_DAC_DeInit
keep and use the user MspInit/MspDeInit callbacks (registered beforehand)
Callbacks can be registered/unregistered in READY state only.
Exception done for MspInit/MspDeInit callbacks that can be registered/unregistered
in READY or RESET state, thus registered (user) MspInit/DeInit callbacks can be used
during the Init/DeInit.
In that case first register the MspInit/MspDeInit user callbacks
using HAL_DAC_RegisterCallback before calling HAL_DAC_DeInit
or HAL_DAC_Init function.
When The compilation define USE_HAL_DAC_REGISTER_CALLBACKS is set to 0 or
not defined, the callback registering feature is not available
and weak (overridden) callbacks are used.
*** DAC HAL driver macros list ***
=============================================
[..]
Below the list of most used macros in DAC HAL driver.
(+) __HAL_DAC_ENABLE : Enable the DAC peripheral
(+) __HAL_DAC_DISABLE : Disable the DAC peripheral
(+) __HAL_DAC_CLEAR_FLAG: Clear the DAC's pending flags
(+) __HAL_DAC_GET_FLAG: Get the selected DAC's flag status
[..]
(@) You can refer to the DAC HAL driver header file for more useful macros 
1.9.6