radio/src/pulses/ppm_arm.cpp

   1 /*
   2  * Copyright (C) OpenTX
   3  *
   4  * Based on code named
   5  *   th9x - http://code.google.com/p/th9x
   6  *   er9x - http://code.google.com/p/er9x
   7  *   gruvin9x - http://code.google.com/p/gruvin9x
   8  *
   9  * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include "opentx.h"
  22
  23 template<class T>
  24 void setupPulsesPPM(uint8_t port, PpmPulsesData<T> * ppmPulsesData)
  25 {
  26   int16_t PPM_range = g_model.extendedLimits ? (512*LIMIT_EXT_PERCENT/100) * 2 : 512 * 2; // range of 0.7 .. 1.7msec
  27
  28   // Total frame length = 22.5msec
  29   // each pulse is 0.7..1.7ms long with a 0.3ms stop tail
  30   // The pulse ISR is 2mhz that's why everything is multiplied by 2
  31
  32   uint32_t firstCh = g_model.moduleData[port].channelsStart;
  33   uint32_t lastCh = min<unsigned int>(MAX_OUTPUT_CHANNELS, firstCh + 8 + g_model.moduleData[port].channelsCount);
  34
  35 #if defined(STM32)
  36   ppmPulsesData->ptr = ppmPulsesData->pulses;
  37 #else
  38   uint16_t * ptr = ppmPulsesData->pulses;
  39   ppmPulsesData->ptr = ptr;
  40 #endif
  41
  42   int32_t rest = 22500u * 2;
  43   rest += (int32_t(g_model.moduleData[port].ppm.frameLength)) * 1000;
  44   for (uint32_t i=firstCh; i<lastCh; i++) {
  45     int16_t v = limit((int16_t)-PPM_range, channelOutputs[i], (int16_t)PPM_range) + 2*PPM_CH_CENTER(i);
  46     rest -= v;
  47 #if defined(STM32)
  48     *ppmPulsesData->ptr++ = v; /* as Pat MacKenzie suggests */
  49 #else
  50     *ptr++ = v; /* as Pat MacKenzie suggests */
  51 #endif
  52   }
  53   rest = limit<int32_t>(9000, rest, 65535); /* avoids that CCR2 is bigger than ARR which would cause reboot */
  54 #if defined(STM32)
  55   *ppmPulsesData->ptr++ = rest;
  56 #else
  57   *ptr = rest;
  58   *(ptr + 1) = 0;
  59 #endif
  60 }
  61
  62 void setupPulsesPPMModule(uint8_t port)
  63 {
  64   setupPulsesPPM<pulse_duration_t>(port, &modulePulsesData[port].ppm);
  65 }
  66
  67 void setupPulsesPPMTrainer()
  68 {
  69   setupPulsesPPM<trainer_pulse_duration_t>(TRAINER_MODULE, &trainerPulsesData.ppm);
  70 }