You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
142 lines
6.7 KiB
Plaintext
142 lines
6.7 KiB
Plaintext
/*
|
|
ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
/**
|
|
* @defgroup ADC ADC Driver
|
|
* @brief Generic ADC Driver.
|
|
* @details This module implements a generic ADC (Analog to Digital Converter)
|
|
* driver supporting a variety of buffer and conversion modes.
|
|
* @pre In order to use the ADC driver the @p HAL_USE_ADC option
|
|
* must be enabled in @p halconf.h.
|
|
*
|
|
* @section adc_1 Driver State Machine
|
|
* The driver implements a state machine internally, not all the driver
|
|
* functionalities can be used in any moment, any transition not explicitly
|
|
* shown in the following diagram has to be considered an error and shall
|
|
* be captured by an assertion (if enabled).
|
|
* @if LATEX_PDF
|
|
* @dot
|
|
digraph example {
|
|
rankdir="LR";
|
|
size="5, 7";
|
|
|
|
node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
|
|
edge [fontname=Helvetica, fontsize=8];
|
|
|
|
stop [label="ADC_STOP\nLow Power"];
|
|
uninit [label="ADC_UNINIT", style="bold"];
|
|
ready [label="ADC_READY\nClock Enabled"];
|
|
active [label="ADC_ACTIVE\nConverting"];
|
|
error [label="ADC_ERROR\nError"];
|
|
complete [label="ADC_COMPLETE\nComplete"];
|
|
|
|
uninit -> stop [label="\n adcInit()", constraint=false];
|
|
stop -> ready [label="\nadcStart()"];
|
|
ready -> ready [label="\nadcStart()\nadcStopConversion()"];
|
|
ready -> stop [label="\nadcStop()"];
|
|
stop -> stop [label="\nadcStop()"];
|
|
ready -> active [label="\nadcStartConversion() (async)\nadcConvert() (sync)"];
|
|
active -> ready [label="\nadcStopConversion()\nsync return"];
|
|
active -> active [label="\nasync callback (half buffer, circular)\nasync callback (full buffer)\n>acg_endcb<"];
|
|
active -> complete [label="\n\nasync callback (full buffer)\n>end_cb<"];
|
|
active -> error [label="\n\nasync callback (error)\n>error_cb<"];
|
|
complete -> active [label="\nadcStartConversionI()\nthen\ncallback return"];
|
|
complete -> ready [label="\ncallback return"];
|
|
error -> active [label="\nadcStartConversionI()\nthen\ncallback return"];
|
|
error -> ready [label="\ncallback return"];
|
|
}
|
|
* @enddot
|
|
* @else
|
|
* @dot
|
|
digraph example {
|
|
rankdir="LR";
|
|
|
|
node [shape=circle, fontname=Helvetica, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
|
|
edge [fontname=Helvetica, fontsize=8];
|
|
|
|
stop [label="ADC_STOP\nLow Power"];
|
|
uninit [label="ADC_UNINIT", style="bold"];
|
|
ready [label="ADC_READY\nClock Enabled"];
|
|
active [label="ADC_ACTIVE\nConverting"];
|
|
error [label="ADC_ERROR\nError"];
|
|
complete [label="ADC_COMPLETE\nComplete"];
|
|
|
|
uninit -> stop [label="\n adcInit()", constraint=false];
|
|
stop -> ready [label="\nadcStart()"];
|
|
ready -> ready [label="\nadcStart()\nadcStopConversion()"];
|
|
ready -> stop [label="\nadcStop()"];
|
|
stop -> stop [label="\nadcStop()"];
|
|
ready -> active [label="\nadcStartConversion() (async)\nadcConvert() (sync)"];
|
|
active -> ready [label="\nadcStopConversion()\nsync return"];
|
|
active -> active [label="\nasync callback (half buffer, circular)\nasync callback (full buffer)\n>acg_endcb<"];
|
|
active -> complete [label="\n\nasync callback (full buffer)\n>end_cb<"];
|
|
active -> error [label="\n\nasync callback (error)\n>error_cb<"];
|
|
complete -> active [label="\nadcStartConversionI()\nthen\ncallback return"];
|
|
complete -> ready [label="\ncallback return"];
|
|
error -> active [label="\nadcStartConversionI()\nthen\ncallback return"];
|
|
error -> ready [label="\ncallback return"];
|
|
}
|
|
* @enddot
|
|
* @endif
|
|
*
|
|
* @section adc_2 ADC Operations
|
|
* The ADC driver is quite complex, an explanation of the terminology and of
|
|
* the operational details follows.
|
|
*
|
|
* @subsection adc_2_1 ADC Conversion Groups
|
|
* The @p ADCConversionGroup is the objects that specifies a physical
|
|
* conversion operation. This structure contains some standard fields and
|
|
* several implementation-dependent fields.<br>
|
|
* The standard fields define the CG mode, the number of channels belonging
|
|
* to the CG and the optional callbacks.<br>
|
|
* The implementation-dependent fields specify the physical ADC operation
|
|
* mode, the analog channels belonging to the group and any other
|
|
* implementation-specific setting. Usually the extra fields just mirror
|
|
* the physical ADC registers, please refer to the vendor's MCU Reference
|
|
* Manual for details about the available settings. Details are also available
|
|
* into the documentation of the ADC low level drivers and in the various
|
|
* sample applications.
|
|
*
|
|
* @subsection adc_2_2 ADC Conversion Modes
|
|
* The driver supports several conversion modes:
|
|
* - <b>One Shot</b>, the driver performs a single group conversion then stops.
|
|
* - <b>Linear Buffer</b>, the driver performs a series of group conversions
|
|
* then stops. This mode is like a one shot conversion repeated N times,
|
|
* the buffer pointer increases after each conversion. The buffer is
|
|
* organized as an S(CG)*N samples matrix, when S(CG) is the conversion
|
|
* group size (number of channels) and N is the buffer depth (number of
|
|
* repeated conversions).
|
|
* - <b>Circular Buffer</b>, much like the linear mode but the operation does
|
|
* not stop when the buffer is filled, it is automatically restarted
|
|
* with the buffer pointer wrapping back to the buffer base.
|
|
* .
|
|
* @subsection adc_2_3 ADC Callbacks
|
|
* The driver is able to invoke callbacks during the conversion process. A
|
|
* callback is invoked when the operation has been completed or, in circular
|
|
* mode, when the buffer has been filled and the operation is restarted. In
|
|
* circular mode a callback is also invoked when the buffer is half filled.<br>
|
|
* The "half filled" and "filled" callbacks in circular mode allow to
|
|
* implement "streaming processing" of the sampled data, while the driver is
|
|
* busy filling one half of the buffer the application can process the
|
|
* other half, this allows for continuous interleaved operations.
|
|
*
|
|
* The driver is not thread safe for performance reasons, if you need to access
|
|
* the ADC bus from multiple threads then use the @p adcAcquireBus() and
|
|
* @p adcReleaseBus() APIs in order to gain exclusive access.
|
|
*
|
|
* @ingroup HAL_NORMAL_DRIVERS
|
|
*/
|