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95 lines
3.3 KiB
95 lines
3.3 KiB
13 years ago
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/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file PWM servo driver.
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*
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* The pwm_servo driver supports servos connected to STM32 timer
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* blocks.
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*
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* Servo values can be set either with the PWM_SERVO_SET ioctl, or
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* by writing an array of servo_position_t values to the device.
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* Writing a value of 0 to a channel suppresses any output for that
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* channel.
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*
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* Servo values can be read back either with the PWM_SERVO_GET
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* ioctl, or by reading an array of servo_position_t values
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* from the device.
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*
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* Attempts to set a channel that is not configured are ignored,
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* and unconfigured channels always read zero.
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*
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* The PWM_SERVO_ARM / PWM_SERVO_DISARM calls globally arm
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* (enable) and disarm (disable) all servo outputs.
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*/
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#include <sys/ioctl.h>
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#define _PWM_SERVO_BASE 0x7500
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#define PWM_SERVO_ARM _IOC(_PWM_SERVO_BASE, 0)
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#define PWM_SERVO_DISARM _IOC(_PWM_SERVO_BASE, 1)
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#define PWM_SERVO_SET(_servo) _IOC(_PWM_SERVO_BASE, 0x20 + _servo)
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#define PWM_SERVO_GET(_servo) _IOC(_PWM_SERVO_BASE, 0x40 + _servo)
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typedef uint16_t servo_position_t;
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/* configuration limits */
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#define PWM_SERVO_MAX_TIMERS 3
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#define PWM_SERVO_MAX_CHANNELS 8
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struct pwm_servo_config {
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/* rate (in Hz) of PWM updates */
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uint32_t update_rate;
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/* array of timers dedicated to PWM servo use */
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struct pwm_servo_timer {
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uint32_t base;
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uint32_t clock_register;
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uint32_t clock_bit;
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uint32_t clock_freq;
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} timers[PWM_SERVO_MAX_TIMERS];
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/* array of channels in logical order */
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struct pwm_servo_channel {
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uint32_t gpio;
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uint8_t timer_index;
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uint8_t timer_channel;
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servo_position_t default_value;
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} channels[PWM_SERVO_MAX_CHANNELS];
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};
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extern int pwm_servo_init(const struct pwm_servo_config *config);
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