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Diffstat (limited to 'os/hal/dox/hal_adc.dox')
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diff --git a/os/hal/dox/hal_adc.dox b/os/hal/dox/hal_adc.dox new file mode 100644 index 000000000..c80a0b495 --- /dev/null +++ b/os/hal/dox/hal_adc.dox @@ -0,0 +1,141 @@ +/*
+ 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
+ */
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