/****************************************************************************
*
* 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
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****************************************************************************/
/**
* @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 the 'ARM ok' bit, which activates the safety switch */
#define PWM_SERVO_SET_ARM_OK _IOC(_PWM_SERVO_BASE, 5)
/** clear the 'ARM ok' bit, which deactivates the safety switch */
#define PWM_SERVO_CLEAR_ARM_OK _IOC(_PWM_SERVO_BASE, 6)
/** 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
