/**************************************************************************** * * 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 mixer.cpp * * Control channel input/output mixer and failsafe. */ #include #include #include #include #include #include #include #include #include #include #include extern "C" { #include "px4io.h" } /* * Count of periodic calls in which we have no FMU input. */ static unsigned fmu_input_drops; #define FMU_INPUT_DROP_LIMIT 20 /* current servo arm/disarm state */ bool mixer_servos_armed = false; /* selected control values and count for mixing */ static uint16_t *control_values; static int control_count; static int mixer_callback(uintptr_t handle, uint8_t control_group, uint8_t control_index, float &control); static MixerGroup mixer_group(mixer_callback, 0); void mixer_tick(void) { bool should_arm; /* * Decide which set of inputs we're using. */ if (system_state.mixer_use_fmu) { /* we have recent control data from the FMU */ control_count = PX4IO_OUTPUT_CHANNELS; control_values = &system_state.fmu_channel_data[0]; /* check that we are receiving fresh data from the FMU */ if (!system_state.fmu_data_received) { fmu_input_drops++; /* too many frames without FMU input, time to go to failsafe */ if (fmu_input_drops >= FMU_INPUT_DROP_LIMIT) { system_state.mixer_use_fmu = false; } } else { fmu_input_drops = 0; system_state.fmu_data_received = false; } } else if (system_state.rc_channels > 0) { /* we have control data from an R/C input */ control_count = system_state.rc_channels; control_values = &system_state.rc_channel_data[0]; } else { /* we have no control input */ /* XXX builtin failsafe would activate here */ control_count = 0; } /* * Run the mixers if we have any control data at all. */ if (control_count > 0) { float outputs[IO_SERVO_COUNT]; unsigned mixed; /* mix */ mixed = mixer_group.mix(&outputs[0], IO_SERVO_COUNT); /* scale to PWM and update the servo outputs as required */ for (unsigned i = 0; i < IO_SERVO_COUNT; i++) { if (i < mixed) { /* scale to servo output */ system_state.servos[i] = (outputs[i] * 1000.0f) + 1000; } else { /* set to zero to inhibit PWM pulse output */ system_state.servos[i] = 0; } /* * If we are armed, update the servo output. */ if (system_state.armed && system_state.arm_ok) up_pwm_servo_set(i, system_state.servos[i]); } } /* * Decide whether the servos should be armed right now. */ should_arm = system_state.armed && system_state.arm_ok && (control_count > 0); if (should_arm && !mixer_servos_armed) { /* need to arm, but not armed */ up_pwm_servo_arm(true); mixer_servos_armed = true; } else if (!should_arm && mixer_servos_armed) { /* armed but need to disarm */ up_pwm_servo_arm(false); mixer_servos_armed = false; } } static int mixer_callback(uintptr_t handle, uint8_t control_group, uint8_t control_index, float &control) { /* if the control index refers to an input that's not valid, we can't return it */ if (control_index >= control_count) return -1; /* scale from current PWM units (1000-2000) to mixer input values */ /* XXX this presents some ugly problems w.r.t failsafe and R/C input scaling that have to be addressed */ control = ((float)control_values[control_index] - 1000.0f) / 1000.0f; return 0; } void mixer_handle_text(const void *buffer, size_t length) { static char mixer_text[256]; static unsigned mixer_text_length = 0; px4io_mixdata *msg = (px4io_mixdata *)buffer; if (length < sizeof(px4io_mixdata)) return; unsigned text_length = length - sizeof(px4io_mixdata); switch (msg->action) { case F2I_MIXER_ACTION_RESET: mixer_group.reset(); mixer_text_length = 0; /* FALLTHROUGH */ case F2I_MIXER_ACTION_APPEND: /* check for overflow - this is really fatal */ if ((mixer_text_length + text_length + 1) > sizeof(mixer_text)) return; /* append mixer text and nul-terminate */ memcpy(&mixer_text[mixer_text_length], msg->text, text_length); mixer_text_length += text_length; mixer_text[mixer_text_length] = '\0'; /* process the text buffer, adding new mixers as their descriptions can be parsed */ char *end = &mixer_text[mixer_text_length]; mixer_group.load_from_buf(&mixer_text[0], mixer_text_length); /* copy any leftover text to the base of the buffer for re-use */ if (mixer_text_length > 0) memcpy(&mixer_text[0], end - mixer_text_length, mixer_text_length); break; } }