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Diffstat (limited to 'src/drivers/drv_pwm_output.h')
| -rw-r--r-- | src/drivers/drv_pwm_output.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/drivers/drv_pwm_output.h b/src/drivers/drv_pwm_output.h new file mode 100644 index 000000000..07831f20c --- /dev/null +++ b/src/drivers/drv_pwm_output.h @@ -0,0 +1,201 @@ +/**************************************************************************** + * + * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name PX4 nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/** + * @file PWM servo output interface. + * + * Servo values can be set with the PWM_SERVO_SET ioctl, by writing a + * pwm_output_values structure to the device, or by publishing to the + * output_pwm ORB topic. + * Writing a value of 0 to a channel suppresses any output for that + * channel. + */ + +#pragma once + +#include <stdint.h> +#include <sys/ioctl.h> + +#include "drv_orb_dev.h" + +__BEGIN_DECLS + +/** + * Path for the default PWM output device. + * + * Note that on systems with more than one PWM output path (e.g. + * PX4FMU with PX4IO connected) there may be other devices that + * respond to this protocol. + */ +#define PWM_OUTPUT_DEVICE_PATH "/dev/pwm_output" + +/** + * Maximum number of PWM output channels supported by the device. + */ +#define PWM_OUTPUT_MAX_CHANNELS 16 + +/** + * Servo output signal type, value is actual servo output pulse + * width in microseconds. + */ +typedef uint16_t servo_position_t; + +/** + * Servo output status structure. + * + * May be published to output_pwm, or written to a PWM output + * device. + */ +struct pwm_output_values { + /** desired pulse widths for each of the supported channels */ + servo_position_t values[PWM_OUTPUT_MAX_CHANNELS]; +}; + +/* + * ORB tag for PWM outputs. + */ +ORB_DECLARE(output_pwm); + +/* + * ioctl() definitions + * + * Note that ioctls and ORB updates should not be mixed, as the + * behaviour of the system in this case is not defined. + */ +#define _PWM_SERVO_BASE 0x2a00 + +/** arm all servo outputs handle by this driver */ +#define PWM_SERVO_ARM _IOC(_PWM_SERVO_BASE, 0) + +/** disarm all servo outputs (stop generating pulses) */ +#define PWM_SERVO_DISARM _IOC(_PWM_SERVO_BASE, 1) + +/** set alternate servo update rate */ +#define PWM_SERVO_SET_UPDATE_RATE _IOC(_PWM_SERVO_BASE, 2) + +/** get the number of servos in *(unsigned *)arg */ +#define PWM_SERVO_GET_COUNT _IOC(_PWM_SERVO_BASE, 3) + +/** selects servo update rates, one bit per servo. 0 = default (50Hz), 1 = alternate */ +#define PWM_SERVO_SELECT_UPDATE_RATE _IOC(_PWM_SERVO_BASE, 4) + +/** set a single servo to a specific value */ +#define PWM_SERVO_SET(_servo) _IOC(_PWM_SERVO_BASE, 0x20 + _servo) + +/** get a single specific servo value */ +#define PWM_SERVO_GET(_servo) _IOC(_PWM_SERVO_BASE, 0x40 + _servo) + +/** get the _n'th rate group's channels; *(uint32_t *)arg returns a bitmap of channels + * whose update rates must be the same. + */ +#define PWM_SERVO_GET_RATEGROUP(_n) _IOC(_PWM_SERVO_BASE, 0x60 + _n) + +/* + * Low-level PWM output interface. + * + * This is the low-level API to the platform-specific PWM driver. + */ + +/** + * Intialise the PWM servo outputs using the specified configuration. + * + * @param channel_mask Bitmask of channels (LSB = channel 0) to enable. + * This allows some of the channels to remain configured + * as GPIOs or as another function. + * @return OK on success. + */ +__EXPORT extern int up_pwm_servo_init(uint32_t channel_mask); + +/** + * De-initialise the PWM servo outputs. + */ +__EXPORT extern void up_pwm_servo_deinit(void); + +/** + * Arm or disarm servo outputs. + * + * When disarmed, servos output no pulse. + * + * @bug This function should, but does not, guarantee that any pulse + * currently in progress is cleanly completed. + * + * @param armed If true, outputs are armed; if false they + * are disarmed. + */ +__EXPORT extern void up_pwm_servo_arm(bool armed); + +/** + * Set the servo update rate for all rate groups. + * + * @param rate The update rate in Hz to set. + * @return OK on success, -ERANGE if an unsupported update rate is set. + */ +__EXPORT extern int up_pwm_servo_set_rate(unsigned rate); + +/** + * Get a bitmap of output channels assigned to a given rate group. + * + * @param group The rate group to query. Rate groups are assigned contiguously + * starting from zero. + * @return A bitmap of channels assigned to the rate group, or zero if + * the group number has no channels. + */ +__EXPORT extern uint32_t up_pwm_servo_get_rate_group(unsigned group); + +/** + * Set the update rate for a given rate group. + * + * @param group The rate group whose update rate will be changed. + * @param rate The update rate in Hz. + * @return OK if the group was adjusted, -ERANGE if an unsupported update rate is set. + */ +__EXPORT extern int up_pwm_servo_set_rate_group_update(unsigned group, unsigned rate); + +/** + * Set the current output value for a channel. + * + * @param channel The channel to set. + * @param value The output pulse width in microseconds. + */ +__EXPORT extern int up_pwm_servo_set(unsigned channel, servo_position_t value); + +/** + * Get the current output value for a channel. + * + * @param channel The channel to read. + * @return The output pulse width in microseconds, or zero if + * outputs are not armed or not configured. + */ +__EXPORT extern servo_position_t up_pwm_servo_get(unsigned channel); + +__END_DECLS |