mirror of https://github.com/ArduPilot/ardupilot
105 lines
2.6 KiB
C
105 lines
2.6 KiB
C
/*
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* Copyright (C) Siddharth Bharat Purohit 2017
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* This file is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This file is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "ppm.h"
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#if HAL_USE_ICU
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static ICUConfig icucfg; //Input Capture Unit Config
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static uint16_t ppm_buffer[10] = {0};
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static bool updated[10] = {0};
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static bool available;
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static uint8_t buf_ptr = 0;
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static uint8_t num_channels = 0;
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static void ppm_measurement_cb(ICUDriver*);
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//Initiallise ppm ICU with requested configuration
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bool ppm_init(uint32_t freq, bool active_high)
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{
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icumode_t ppm_active_mode;
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if (active_high) {
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ppm_active_mode = ICU_INPUT_ACTIVE_HIGH;
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} else {
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ppm_active_mode = ICU_INPUT_ACTIVE_LOW;
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}
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icucfg.mode = ppm_active_mode;
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icucfg.frequency = freq;
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icucfg.channel = PPM_ICU_CHANNEL;
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icucfg.width_cb = NULL;
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icucfg.period_cb = ppm_measurement_cb;
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icucfg.overflow_cb = NULL;
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icucfg.dier = 0;
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icuStart(&HAL_ICU_TIMER, &icucfg);
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icuStartCapture(&HAL_ICU_TIMER);
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icuEnableNotifications(&HAL_ICU_TIMER);
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return true;
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}
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uint16_t ppm_read(uint8_t channel)
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{
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//return 0 if channel requested is out range
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if(channel >= num_channels) {
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return 0;
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}
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updated[channel] = false;
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return ppm_buffer[channel];
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}
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uint8_t ppm_read_bulk(uint16_t periods[], uint8_t len)
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{
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uint8_t i;
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for(i = 0; (i < num_channels) && (i < len); i++) {
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periods[i] = ppm_buffer[i];
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}
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return i;
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}
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bool ppm_available()
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{
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uint8_t i;
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for (i = 0; i < 10; i++) {
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if (updated[i]) {
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return true;
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}
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}
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return false;
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}
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uint8_t ppm_num_channels()
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{
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return num_channels;
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}
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static void ppm_measurement_cb(ICUDriver *icup)
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{
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uint16_t period = icuGetPeriodX(icup);
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if (period >= 2700 || buf_ptr >= 10) {
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//This is a sync pulse let's reset buffer pointer
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num_channels = buf_ptr + 1;
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buf_ptr = 0;
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} else {
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if(period > 900) {
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updated[buf_ptr] = true;
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ppm_buffer[buf_ptr] = period;
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}
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buf_ptr++;
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}
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}
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#endif // HAL_USE_ICU
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