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Diffstat (limited to 'apps/px4io/mixer.cpp')
-rw-r--r-- | apps/px4io/mixer.cpp | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/apps/px4io/mixer.cpp b/apps/px4io/mixer.cpp new file mode 100644 index 000000000..6af1dd3dc --- /dev/null +++ b/apps/px4io/mixer.cpp @@ -0,0 +1,212 @@ +/**************************************************************************** + * + * 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 <nuttx/config.h> +#include <nuttx/arch.h> + +#include <sys/types.h> +#include <stdbool.h> +#include <string.h> +#include <assert.h> +#include <errno.h> +#include <unistd.h> +#include <fcntl.h> + +#include <drivers/drv_pwm_output.h> +#include <systemlib/mixer/mixer.h> + +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; + } +}
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