From a3e9966359c432405c8ab1eb49a27133e5271ba2 Mon Sep 17 00:00:00 2001 From: Giovanni Di Sirio Date: Mon, 21 Jan 2019 19:42:49 +0000 Subject: More renaming for consistency. git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@12571 110e8d01-0319-4d1e-a829-52ad28d1bb01 --- os/hal/dox/hal_pwm.dox | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 os/hal/dox/hal_pwm.dox (limited to 'os/hal/dox/hal_pwm.dox') diff --git a/os/hal/dox/hal_pwm.dox b/os/hal/dox/hal_pwm.dox new file mode 100644 index 000000000..39e0128b1 --- /dev/null +++ b/os/hal/dox/hal_pwm.dox @@ -0,0 +1,65 @@ +/* + 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 PWM PWM Driver + * @brief Generic PWM Driver. + * @details This module implements a generic PWM (Pulse Width Modulation) + * driver. + * @pre In order to use the PWM driver the @p HAL_USE_PWM option + * must be enabled in @p halconf.h. + * + * @section pwm_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). + * @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]; + uninit [label="PWM_UNINIT", style="bold"]; + stop [label="PWM_STOP\nLow Power"]; + ready [label="PWM_READY\nClock Enabled"]; + uninit -> stop [label="pwmInit()"]; + stop -> stop [label="pwmStop()"]; + stop -> ready [label="pwmStart()"]; + ready -> stop [label="pwmStop()"]; + ready -> ready [label="pwmEnableChannel()\npwmDisableChannel()"]; + } + * @enddot + * + * @section pwm_2 PWM Operations. + * This driver abstracts a generic PWM timer composed of: + * - A clock prescaler. + * - A main up counter. + * - A comparator register that resets the main counter to zero when the limit + * is reached. An optional callback can be generated when this happens. + * - An array of @p PWM_CHANNELS PWM channels, each channel has an output, + * a comparator and is able to invoke an optional callback when a comparator + * match with the main counter happens. + * . + * A PWM channel output can be in two different states: + * - IDLE, when the channel is disabled or after a match occurred. + * - ACTIVE, when the channel is enabled and a match didn't occur yet + * in the current PWM cycle. + * . + * Note that the two states can be associated to both logical zero or one in + * the @p PWMChannelConfig structure. + * + * @ingroup HAL_NORMAL_DRIVERS + */ -- cgit v1.2.3