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108 lines
4.2 KiB
Plaintext
108 lines
4.2 KiB
Plaintext
/*
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ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @defgroup ICU ICU Driver
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* @brief Generic ICU Driver.
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* @details This module implements a generic ICU (Input Capture Unit) driver.
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* The purpose of the driver is to measure period and duty cycle of
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* an input digital signal (PWM input).
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* @pre In order to use the ICU driver the @p HAL_USE_ICU option
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* must be enabled in @p halconf.h.
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*
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* @section icu_1 Driver State Machine
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* The driver implements a state machine internally, not all the driver
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* functionalities can be used in any moment, any transition not explicitly
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* shown in the following diagram has to be considered an error and shall
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* be captured by an assertion (if enabled).
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* @if LATEX_PDF
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* @dot
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digraph example {
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size="5, 7";
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rankdir="LR";
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node [shape=circle, fontname=Sans, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
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edge [fontname=Sans, fontsize=8];
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stop [label="ICU_STOP\nLow Power"];
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uninit [label="ICU_UNINIT", style="bold"];
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ready [label="ICU_READY\nClock Enabled"];
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waiting [label="ICU_WAITING"];
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active [label="ICU_ACTIVE"];
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uninit -> stop [label=" icuInit()", constraint=false];
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stop -> stop [label="\nicuStop()"];
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stop -> ready [label="\nicuStart()"];
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ready -> stop [label="\nicuStop()"];
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ready -> ready [label="\nicuStart()\nicuStopCapture()"];
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ready -> waiting [label="\nicuStartCapture()"];
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waiting -> active [label="\nFirst Activation Edge\nicuWaitCapture()"];
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waiting -> ready [label="\nicuStopCapture()"];
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active -> ready [label="\nicuStopCapture()"];
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active -> active [label="\nActivation Edge\n>period_cb<"];
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active -> active [label="\nDe-activation Edge\n>width_cb<"];
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}
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* @enddot
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* @else
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* @dot
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digraph example {
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rankdir="LR";
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node [shape=circle, fontname=Sans, fontsize=8, fixedsize="true", width="0.9", height="0.9"];
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edge [fontname=Sans, fontsize=8];
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stop [label="ICU_STOP\nLow Power"];
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uninit [label="ICU_UNINIT", style="bold"];
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ready [label="ICU_READY\nClock Enabled"];
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waiting [label="ICU_WAITING"];
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active [label="ICU_ACTIVE"];
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uninit -> stop [label=" icuInit()", constraint=false];
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stop -> stop [label="\nicuStop()"];
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stop -> ready [label="\nicuStart()"];
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ready -> stop [label="\nicuStop()"];
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ready -> ready [label="\nicuStart()\nicuStopCapture()"];
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ready -> waiting [label="\nicuStartCapture()"];
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waiting -> active [label="\nFirst Activation Edge\nicuWaitCapture()"];
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waiting -> ready [label="\nicuStopCapture()"];
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active -> ready [label="\nicuStopCapture()"];
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active -> active [label="\nActivation Edge\n>period_cb<"];
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active -> active [label="\nDe-activation Edge\n>width_cb<"];
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}
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* @enddot
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* @endif
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*
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* @section icu_2 ICU Operations.
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* This driver abstracts a generic Input Capture Unit composed of:
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* - A clock prescaler.
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* - A main up counter.
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* - Two capture registers triggered by the rising and falling edges on
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* the sampled input.
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* .
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* The ICU unit can be programmed to synchronize on the rising or falling
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* edge of the sample input:
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* - <b>ICU_INPUT_ACTIVE_HIGH</b>, a rising edge is the start signal.
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* - <b>ICU_INPUT_ACTIVE_LOW</b>, a falling edge is the start signal.
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* .
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* Callbacks are optionally invoked when:
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* - On the PWM de-activation edge.
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* - On the PWM activation edge, measurements for the previous cycle are
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* available from this callback and can be retrieved using
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* @p icuGetPeriodX() and @p icuGetWidthX().
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* .
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* @ingroup HAL_NORMAL_DRIVERS
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*/
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