flight/pios/inc/pios_dsm_priv.h

   1 /**
   2  ******************************************************************************
   3  * @addtogroup PIOS PIOS Core hardware abstraction layer
   4  * @{
   5  * @addtogroup PIOS_DSM Spektrum/JR DSMx satellite receiver functions
   6  * @brief PIOS interface to bind and read Spektrum/JR DSMx satellite receiver
   7  * @{
   8  *
   9  * @file       pios_dsm_priv.h
  10  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2011.
  11  * @brief      Spektrum/JR DSMx satellite receiver private structures.
  12  * @see        The GNU Public License (GPL) Version 3
  13  *
  14  *****************************************************************************/
  15 /*
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 3 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful, but
  22  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  23  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  24  * for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License along
  27  * with this program; if not, write to the Free Software Foundation, Inc.,
  28  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29  */
  30
  31 #ifndef PIOS_DSM_PRIV_H
  32 #define PIOS_DSM_PRIV_H
  33
  34 #include <pios.h>
  35 #include <pios_stm32.h>
  36 #include <pios_usart_priv.h>
  37
  38 /*
  39  * Currently known DSMx (DSM2, DSMJ, DSMX) satellite serial port settings:
  40  *  115200bps serial stream, 8 bits, no parity, 1 stop bit
  41  *  size of each frame: 16 bytes
  42  *  data resolution: 10 or 11 bits
  43  *  number of frames: 1 or 2
  44  *  frame period: 11ms or 22ms
  45  *
  46  * Currently known DSMx frame structure:
  47  *  2 bytes - depend on protocol version:
  48  *    for DSM2/DSMJ:
  49  *      1 byte - lost frame counter (8 bit)
  50  *      1 byte - data format (for master receiver bound with 3 or 5 pulses),
  51  *               or unknown (for slave receiver bound with 4 or 6 pulses,
  52  *               some sources call it also the lost frame counter)
  53  *    for DSMX:
  54  *      1 byte - unknown data (does not look like lost frame counter)
  55  *      1 byte - unknown data, has been seen only 0xB2 so far
  56
  57  * 14 bytes - up to 7 channels (16 bit word per channel) with encoded channel
  58  *            number, channel value, the "2nd frame in a sequence" flag.
  59  *            Unused channels have FF FF instead of data bytes.
  60  *
  61  * Data format identification:
  62  *   - for DSM2/DSMJ: [0 0 0 R 0 0 N1 N0]
  63  *     where
  64  *        R is data resolution (0 - 10 bits, 1 - 11 bits),
  65  *        N1..N0 is the number of frames required to receive all channel
  66  *        data (01 or 10 are known to the moment, which means 1 or 2 frames).
  67  *        Three values for the transmitter information byte have been seen
  68  *        thus far: 0x01, 0x02, 0x12.
  69  *   - for DSMX this byte contains just 0xB2 or 0xA2 value for any resolution.
  70  *     It is not known at the moment how to find the exact resolution from the
  71  *     DSMX data stream. The frame number (1 or 2) and 10/11 bit resolution were
  72  *     found in different data streams. So it is safer at the moment to ask user
  73  *     explicitly choose the resolution.
  74  *     Also some weird throttle channel (0) behavior was found in some streams
  75  *     from DX8 transmitter (all zeroes). Thus DSMX needs special processing.
  76  *
  77  * Channel data are:
  78  * - for 10 bit: [F 0 C3 C2 C1 C0 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0]
  79  * - for 11 bit: [F C3 C2 C1 C0 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0]
  80  *   where
  81  *      F is normally 0 but set to 1 for the first channel of the 2nd frame,
  82  *      C3 to C0 is the channel number, 4 bit, zero-based, in any order,
  83  *      Dx..D0 - channel data (10 or 11 bits)
  84  *
  85  * DSM2 protocol bug: in some cases in 2-frame format some bytes of the
  86  * frame can contain invalid values from the previous frame. They usually
  87  * are the last 5 bytes and can be equal to FF or other data from last
  88  * frame. There is no explicit workaround currently known.
  89  *
  90  * Binding: the number of pulses within bind window after power up defines
  91  * if this receiver is a master (provides receiver capabilities info to
  92  * the transmitter to choose data format) or slave (does not respond to
  93  * the transmitter which falls back to the old DSM mode in that case).
  94  * Currently known are 3(4) pulses for low resolution (10 bit) DSM2 mode,
  95  * 5(6) pulses for high resolution (11 bit) DSM2 mode, and also 7(8) and
  96  * 9(10) pulses for DSMX modes. Thus only 3, 5, 7 or 9 pulses should be
  97  * used for stand-alone satellite receiver to be bound correctly as the
  98  * master.
  99  */
 100
 101 #define DSM_CHANNELS_PER_FRAME 7
 102 #define DSM_FRAME_LENGTH       (1 + 1 + DSM_CHANNELS_PER_FRAME * 2)
 103 #define DSM_2ND_FRAME_MASK     0x8000
 104 /* lower this value as needed if your satellite requires less delay to enter binding. */
 105 #define DSM_BIND_MIN_DELAY_US  90000
 106 /*
 107  * Include lost frame counter and provide it as a last channel value
 108  * for debugging. Currently is not used by the receiver layer.
 109  */
 110 // #define DSM_LOST_FRAME_COUNTER
 111
 112 extern const struct pios_rcvr_driver pios_dsm_rcvr_driver;
 113
 114 extern int32_t PIOS_DSM_Init(uint32_t *dsm_id,
 115                              const struct pios_com_driver *driver,
 116                              uint32_t lower_id,
 117                              uint8_t bind);
 118
 119 #endif /* PIOS_DSM_PRIV_H */
 120
 121 /**
 122  * @}
 123  * @}
 124  */