src/main/telemetry/ibus.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /*
  22  * FlySky iBus telemetry implementation by CraigJPerry.
  23  * Unit tests and some additions by Unitware
  24  *
  25  * Many thanks to Dave Borthwick's iBus telemetry dongle converter for
  26  * PIC 12F1572 (also distributed under GPLv3) which was referenced to
  27  * clarify the protocol.
  28  */
  29
  30 #include <stdbool.h>
  31 #include <stdint.h>
  32 #include <string.h>
  33
  34 #include "platform.h"
  35
  36 #if defined(USE_TELEMETRY_IBUS)
  37
  38 #include "common/axis.h"
  39
  40 #include "common/utils.h"
  41
  42 #include "pg/pg.h"
  43 #include "pg/pg_ids.h"
  44
  45 #include "drivers/accgyro/accgyro.h"
  46 #include "drivers/sensor.h"
  47 #include "drivers/serial.h"
  48
  49 #include "fc/rc_controls.h"
  50
  51 #include "io/serial.h"
  52
  53 #include "sensors/acceleration.h"
  54 #include "sensors/battery.h"
  55 #include "sensors/barometer.h"
  56 #include "sensors/gyro.h"
  57 #include "sensors/sensors.h"
  58
  59 #include "scheduler/scheduler.h"
  60
  61 #include "telemetry/ibus.h"
  62 #include "telemetry/ibus_shared.h"
  63 #include "telemetry/telemetry.h"
  64
  65
  66 #define IBUS_TASK_PERIOD_US (1000)
  67
  68 #define IBUS_UART_MODE     (MODE_RXTX)
  69 #define IBUS_BAUDRATE      (115200)
  70 #define IBUS_CYCLE_TIME_MS (8)
  71
  72 #define IBUS_MIN_LEN       (2 + IBUS_CHECKSUM_SIZE)
  73 #define IBUS_MAX_TX_LEN    (6)
  74 #define IBUS_MAX_RX_LEN    (4)
  75 #define IBUS_RX_BUF_LEN    (IBUS_MAX_RX_LEN)
  76
  77
  78 static serialPort_t *ibusSerialPort = NULL;
  79 static const serialPortConfig_t *ibusSerialPortConfig;
  80
  81 /* The sent bytes will be echoed back since Tx and Rx are wired together, this counter
  82  * will keep track of how many rx chars that shall be discarded */
  83 static uint8_t outboundBytesToIgnoreOnRxCount = 0;
  84
  85 static bool ibusTelemetryEnabled = false;
  86 static portSharing_e ibusPortSharing;
  87
  88 static uint8_t ibusReceiveBuffer[IBUS_RX_BUF_LEN] = { 0x0 };
  89
  90
  91
  92 static void pushOntoTail(uint8_t buffer[IBUS_MIN_LEN], size_t bufferLength, uint8_t value)
  93 {
  94     memmove(buffer, buffer + 1, bufferLength - 1);
  95     ibusReceiveBuffer[bufferLength - 1] = value;
  96 }
  97
  98
  99 void initIbusTelemetry(void)
 100 {
 101     ibusSerialPortConfig = findSerialPortConfig(FUNCTION_TELEMETRY_IBUS);
 102     ibusPortSharing = determinePortSharing(ibusSerialPortConfig, FUNCTION_TELEMETRY_IBUS);
 103     ibusTelemetryEnabled = false;
 104 }
 105
 106
 107 void handleIbusTelemetry(void)
 108 {
 109     if (!ibusTelemetryEnabled) {
 110         return;
 111     }
 112
 113     while (serialRxBytesWaiting(ibusSerialPort) > 0) {
 114         uint8_t c = serialRead(ibusSerialPort);
 115
 116         if (outboundBytesToIgnoreOnRxCount) {
 117             outboundBytesToIgnoreOnRxCount--;
 118             continue;
 119         }
 120
 121         pushOntoTail(ibusReceiveBuffer, IBUS_RX_BUF_LEN, c);
 122
 123         if (isChecksumOkIa6b(ibusReceiveBuffer, IBUS_RX_BUF_LEN)) {
 124             outboundBytesToIgnoreOnRxCount += respondToIbusRequest(ibusReceiveBuffer);
 125         }
 126     }
 127 }
 128
 129
 130 bool checkIbusTelemetryState(void)
 131 {
 132     bool newTelemetryEnabledValue = telemetryDetermineEnabledState(ibusPortSharing);
 133
 134     if (newTelemetryEnabledValue == ibusTelemetryEnabled) {
 135         return false;
 136     }
 137
 138     if (newTelemetryEnabledValue) {
 139         rescheduleTask(TASK_TELEMETRY, IBUS_TASK_PERIOD_US);
 140         configureIbusTelemetryPort();
 141     } else {
 142         freeIbusTelemetryPort();
 143     }
 144
 145     return true;
 146 }
 147
 148
 149 void configureIbusTelemetryPort(void)
 150 {
 151     if (!ibusSerialPortConfig) {
 152         return;
 153     }
 154
 155     if (isSerialPortShared(ibusSerialPortConfig, FUNCTION_RX_SERIAL, FUNCTION_TELEMETRY_IBUS)) {
 156         // serialRx will open port and handle telemetry
 157         return;
 158     }
 159
 160     ibusSerialPort = openSerialPort(ibusSerialPortConfig->identifier, FUNCTION_TELEMETRY_IBUS, NULL, NULL, IBUS_BAUDRATE, IBUS_UART_MODE, SERIAL_BIDIR | (telemetryConfig()->telemetry_inverted ? SERIAL_INVERTED : SERIAL_NOT_INVERTED));
 161
 162     if (!ibusSerialPort) {
 163         return;
 164     }
 165
 166     initSharedIbusTelemetry(ibusSerialPort);
 167     ibusTelemetryEnabled = true;
 168     outboundBytesToIgnoreOnRxCount = 0;
 169 }
 170
 171
 172 void freeIbusTelemetryPort(void)
 173 {
 174     closeSerialPort(ibusSerialPort);
 175     ibusSerialPort = NULL;
 176     ibusTelemetryEnabled = false;
 177 }
 178
 179 #endif