Adapt a library to a Teensy 4.0

pierrotm777 · Apr 24, 2025

Hello,
I use a library for simulate Frsky Hub telemetry.
This Lib is running well with Atmega 328 and Teensy 3.x and LC but not with Teensy 4.0.

Can you help me to adapt this lib for a Teensy 4.0 please.

Code:

/*
  FrSky Telemetry for Teensy 3.x/LC and 328P/168 based boards (e.g. Pro Mini, Nano, Uno)
  (c) Pawelsky 20170831
  Not for commercial use
*/

#include "FrSkyTelemetry.h"

FrSkyTelemetry::FrSkyTelemetry() : enabledSensors(SENSOR_NONE), cellIdx(0), frame1Time(0), frame2Time(0), frame3Time(0) {}

void FrSkyTelemetry::begin(FrSkyTelemetry::SerialId id)
{
#if defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MKL26Z64__) || defined(__MK66FX1M0__) || defined(__MK64FX512__)
  if(id == SERIAL_USB) // Not really a telemetry port, but added for debug purposes via USB
  {
    port = &Serial;
    Serial.begin(9600);
  }
  else if(id == SERIAL_1)
  {
    port = &Serial1;
    Serial1.begin(9600);
    UART0_C3 = 0x10;  // Invert Serial1 Tx levels
  }
  else if(id == SERIAL_2)
  {
    port = &Serial2;
    Serial2.begin(9600);
    UART1_C3 = 0x10;  // Invert Serial2 Tx levels
  }
  else if(id == SERIAL_3)
  {
    port = &Serial3;
    Serial3.begin(9600);
    UART2_C3 = 0x10;  // Invert Serial3 Tx levels
  }
  #if defined(__MK66FX1M0__) || defined(__MK64FX512__)
  else if(id == SERIAL_4)
  {
    port = &Serial4;
    Serial4.begin(9600);
    UART3_C3 = 0x10;  // Invert Serial4 Tx levels
  }
  else if(id == SERIAL_5)
  {
    port = &Serial5;
    Serial5.begin(9600);
    UART4_C3 = 0x10;  // Invert Serial5 Tx levels
  }
  else if(id == SERIAL_6)
  {
    port = &Serial6;
    Serial6.begin(9600);
    UART5_C3 = 0x10;  // Invert Serial6 Tx levels
  }
  #endif
#elif defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
  if(softSerial != NULL)
  {
    delete softSerial;
    softSerial = NULL;
  }
  softSerial = new SoftwareSerial(id, id, true);
  port = softSerial;
  softSerial->begin(9600);
  pinMode(id, OUTPUT);
#else
  #error "Unsupported processor! Only Teesny 3.x and 328P/168 based processors supported.";
#endif
}

void FrSkyTelemetry::setFgsData(float fuel)
{
  enabledSensors |= SENSOR_FGS;
  FrSkyTelemetry::fuel = (uint16_t)round(fuel);
}

void FrSkyTelemetry::setFlvsData(float cell1, float cell2, float cell3, float cell4, float cell5, float cell6,
                                 float cell7, float cell8, float cell9, float cell10, float cell11, float cell12)
{
  enabledSensors |= SENSOR_FLVS;
  // DEVIATION FROM SPEC: in reality cells are numbered from 0 not from 1 like in the FrSky protocol spec
  FrSkyTelemetry::cell[0] = 0x0000 | (uint16_t)round(cell1 * 500.0);
  if(cell2  != 0) FrSkyTelemetry::cell[1]  = 0x1000 | (uint16_t)round(cell2  * 500.0);
  if(cell3  != 0) FrSkyTelemetry::cell[2]  = 0x2000 | (uint16_t)round(cell3  * 500.0);
  if(cell4  != 0) FrSkyTelemetry::cell[3] = 0x3000 | (uint16_t)round(cell4  * 500.0);
  if(cell5  != 0) FrSkyTelemetry::cell[4]  = 0x4000 | (uint16_t)round(cell5  * 500.0);
  if(cell6  != 0) FrSkyTelemetry::cell[5]  = 0x5000 | (uint16_t)round(cell6  * 500.0);
  if(cell7  != 0) FrSkyTelemetry::cell[6]  = 0x6000 | (uint16_t)round(cell7  * 500.0);
  if(cell8  != 0) FrSkyTelemetry::cell[7]  = 0x7000 | (uint16_t)round(cell8  * 500.0);
  if(cell9  != 0) FrSkyTelemetry::cell[8]  = 0x8000 | (uint16_t)round(cell9  * 500.0);
  if(cell10 != 0) FrSkyTelemetry::cell[9]  = 0x9000 | (uint16_t)round(cell10 * 500.0);
  if(cell11 != 0) FrSkyTelemetry::cell[10] = 0xA000 | (uint16_t)round(cell11 * 500.0);
  if(cell12 != 0) FrSkyTelemetry::cell[11] = 0xB000 | (uint16_t)round(cell12 * 500.0);
}

void FrSkyTelemetry::setFasData(float current, float voltage)
{
  enabledSensors |= SENSOR_FAS;
  // DEVIATION FROM SPEC: FrSky protocol spec suggests 0.5 ratio, but in reality this ratio is 0.5238 (based on the information from internet).
  voltage *= 0.5238;
  FrSkyTelemetry::voltageBD = (uint16_t)voltage;
  FrSkyTelemetry::voltageAD = (uint16_t)round((voltage - voltageBD) * 10.0);
  FrSkyTelemetry::current = (uint16_t)round(current * 10.0);
}

void FrSkyTelemetry::setFvasData(float alt, float vsi)
{
  enabledSensors |= SENSOR_FVAS;
  FrSkyTelemetry::altBD = (int16_t)alt;
  FrSkyTelemetry::altAD = abs((int16_t)round((alt - FrSkyTelemetry::altBD) * 100.0));
  FrSkyTelemetry::vsi = (int16_t)(vsi * 100.0);
}

void FrSkyTelemetry::setGpsData(float lat, float lon, float alt, float speed, float cog, uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second)
{
  enabledSensors |= SENSOR_GPS;
  FrSkyTelemetry::latNS = (uint16_t)(lat < 0 ? 'S' : 'N'); if(lat < 0) lat = -lat;
  FrSkyTelemetry::latBD = (uint16_t)lat;
  lat = (lat - (float)FrSkyTelemetry::latBD) * 60.0;
  FrSkyTelemetry::latBD = FrSkyTelemetry::latBD * 100 + (uint16_t)lat;
  FrSkyTelemetry::latAD = (uint16_t)round((lat - (uint16_t)lat) * 10000.0);
  FrSkyTelemetry::lonEW = (uint16_t)(lon < 0 ? 'W' : 'E');  if(lon < 0) lon = -lon;
  FrSkyTelemetry::lonBD = (uint16_t)lon;
  lon = (lon - (float)FrSkyTelemetry::lonBD) * 60.0;
  FrSkyTelemetry::lonBD = FrSkyTelemetry::lonBD * 100 + (uint16_t)lon;
  FrSkyTelemetry::lonAD = (uint16_t)round((lon - (uint16_t)lon) * 10000.0);
  FrSkyTelemetry::gpsAltBD = (int16_t)alt;
  FrSkyTelemetry::gpsAltAD = abs((int16_t)round((alt - FrSkyTelemetry::gpsAltBD) * 100.0));
  speed *= 1.94384; // Convert m/s to knots
  FrSkyTelemetry::speedBD = (uint16_t)speed;
  FrSkyTelemetry::speedAD = (uint16_t)round((speed - FrSkyTelemetry::speedBD) * 100.0);
  FrSkyTelemetry::cogBD = (uint16_t)cog;
  FrSkyTelemetry::cogAD = (uint16_t)round((cog - FrSkyTelemetry::cogBD) * 100.0);
  FrSkyTelemetry::year  = (uint16_t)(year);
  FrSkyTelemetry::dayMonth = (uint16_t)day; FrSkyTelemetry::dayMonth <<= 8; FrSkyTelemetry::dayMonth |= (uint16_t)month;
  FrSkyTelemetry::hourMinute = (uint16_t)hour; FrSkyTelemetry::hourMinute <<= 8; FrSkyTelemetry::hourMinute |= (uint16_t)minute;
  FrSkyTelemetry::second = (uint16_t)second;
}

void FrSkyTelemetry::setTasData(float accX, float accY, float accZ)
{
  enabledSensors |= SENSOR_TAS;
  FrSkyTelemetry::accX = (int16_t)round(accX * 1000.0);
  FrSkyTelemetry::accY = (int16_t)round(accY * 1000.0);
  FrSkyTelemetry::accZ = (int16_t)round(accZ * 1000.0);
}

void FrSkyTelemetry::setTemsData(float t1, float t2)
{
  enabledSensors |= SENSOR_TEMS;
  FrSkyTelemetry::t1 = (int16_t)round(t1);
  FrSkyTelemetry::t2 = (int16_t)round(t2);
}

void FrSkyTelemetry::setRpmsData(float rpm)
{
  enabledSensors |= SENSOR_RPMS;
  FrSkyTelemetry::rpm = (uint16_t)round(rpm / 30.0);
}

void FrSkyTelemetry::sendSeparator()
{
  if(port != NULL)
  {
    port->write(0x5E);
  }
}

void FrSkyTelemetry::sendByte(uint8_t byte)
{
  if(port != NULL)
  {
    if(byte == 0x5E) // use 5D 3E sequence instead of 5E to distinguish between separator character and real data
    {
      port->write(0x5D);
      port->write(0x3E);
    }
    else if(byte == 0x5D) // use 5D 3D sequence instead of 5D to distinguish between stuffing character and real data
    {
      port->write(0x5D);
      port->write(0x3D);
    }
    else
    {
      port->write(byte);
    }
    if(port != NULL) port->flush();
  }
}

void FrSkyTelemetry::sendData(uint8_t dataId, uint16_t data, bool bigEndian)
{
  sendSeparator();
  sendByte(dataId);
  uint8_t *bytes = (uint8_t*)&data;
  if(bigEndian == false)
  {
    sendByte(bytes[0]);
    sendByte(bytes[1]);
  }
  else
  {
    sendByte(bytes[1]);
    sendByte(bytes[0]);
  }
  if(port != NULL) port->flush();
}

bool FrSkyTelemetry::sendFasData()
{
  bool enabled = enabledSensors & SENSOR_FAS;
  if(enabled == true)
  {
    sendData(0x28, current);
    sendData(0x3A, voltageBD);
    sendData(0x3B, voltageAD);
  }
  return enabled;
}

bool FrSkyTelemetry::sendFgsData()
{
  bool enabled = enabledSensors & SENSOR_FGS;
  if(enabled == true)
  {
    sendData(0x04, fuel);
  }
  return enabled;
}

bool FrSkyTelemetry::sendFlvsData()
{
  bool enabled = enabledSensors & SENSOR_FLVS;
  if(enabled == true)
  {
    // Only send one cell at a time
    if((cell[cellIdx] == 0) || (cellIdx == 12)) cellIdx = 0;
    sendData(0x06, cell[cellIdx], true); 
    cellIdx++;
  }
  return enabled;
}

bool FrSkyTelemetry::sendFvasData()
{
  bool enabled = enabledSensors & SENSOR_FVAS;
  if(enabled == true)
  {
    sendData(0x10, altBD);
    sendData(0x21, altAD);
    sendData(0x30, vsi); // Not documented in FrSky spec, added based on OpenTX sources.
  }
  return enabled;
}

bool FrSkyTelemetry::sendGpsData()
{
  bool enabled = enabledSensors & SENSOR_GPS;
  if(enabled == true)
  {
    sendData(0x01, gpsAltBD); 
    sendData(0x09, gpsAltAD); 
    sendData(0x11, speedBD); 
    sendData(0x19, speedAD); 
    sendData(0x12, lonBD); // DEVIATION FROM SPEC: FrSky protocol spec says lat shall be sent as big endian, but it reality little endian is expected
    sendData(0x1A, lonAD); // DEVIATION FROM SPEC: FrSky protocol spec says lat shall be sent as big endian, but it reality little endian is expected
    sendData(0x22, lonEW); // DEVIATION FROM SPEC: FrSky protocol spec says lon shall be sent as big endian, but it reality little endian is expected
    sendData(0x13, latBD); // DEVIATION FROM SPEC: FrSky protocol spec says lon shall be sent as big endian, but it reality little endian is expected
    sendData(0x1B, latAD); 
    sendData(0x23, latNS); 
    sendData(0x14, cogBD); 
    sendData(0x1C, cogAD); 
  }
  return enabled;
}

bool FrSkyTelemetry::sendDateTimeData()
{
  bool enabled = enabledSensors & SENSOR_GPS;
  if(enabled == true)
  {
    sendData(0x15, dayMonth, true); 
    sendData(0x16, year); 
    sendData(0x17, hourMinute, true); 
    sendData(0x18, second); 
  }
  return enabled;
}

bool FrSkyTelemetry::sendTasData()
{
  bool enabled = enabledSensors & SENSOR_TAS;
  if(enabled == true)
  {
    sendData(0x24, accX); 
    sendData(0x25, accY); 
    sendData(0x26, accZ); 
  }
  return enabled;
}

bool FrSkyTelemetry::sendTemsData()
{
  bool enabled = enabledSensors & SENSOR_TEMS;
  if(enabled == true)
  {
    sendData(0x02, t1); 
    sendData(0x05, t2);
  }
  return enabled;
}
  
bool FrSkyTelemetry::sendRpmsData()
{
  bool enabled = enabledSensors & SENSOR_RPMS;
  if(enabled == true)
  {
    sendData(0x03, rpm);
  }
  return enabled;
}

void FrSkyTelemetry::sendFrame1()
{
  bool result = false;
  result  = sendFasData();
  result |= sendFlvsData();
  result |= sendFvasData();
  result |= sendTasData();
  result |= sendTemsData();
  result |= sendRpmsData();
  if (result == true) sendSeparator();
}

void FrSkyTelemetry::sendFrame2()
{
  bool result = false;
  result  = sendFgsData();
  result |= sendGpsData();
  if (result == true) sendSeparator();
}

void FrSkyTelemetry::sendFrame3()
{
  bool result = false;
  result = sendDateTimeData();
  if (result == true) sendSeparator();
}

void FrSkyTelemetry::send()
{
  uint32_t currentTime = millis();
  if(currentTime > frame3Time) // Sent every 5s (5000ms)
  {
    frame3Time = currentTime + 5000;
    frame2Time = currentTime + 200; // Postpone frame 2 to next cycle
    frame1Time = currentTime + 200; // Postpone frame 1 to next cycle
    sendFrame3();
  }
  else if(currentTime > frame2Time) // Sent every 1s (1000ms)
  {
    frame2Time = currentTime + 2000;
    frame1Time = currentTime + 200; // Postpone frame 1 to next cycle
    sendFrame2();
  }
  else if(currentTime > frame1Time) // Sent every 200ms
  {
    frame1Time = currentTime + 200;
    sendFrame1();
  }
}

Code:

/*
  FrSky Telemetry for Teensy 3.x/LC and 328P/168 based boards (e.g. Pro Mini, Nano, Uno)
  (c) Pawelsky 20170831
  Not for commercial use
*/

#ifndef _FRSKY_TELEMETRY_H_
#define _FRSKY_TELEMETRY_H_

#include "Arduino.h"
#if !defined(__MK20DX128__) && !defined(__MK20DX256__) && !defined(__MKL26Z64__) && !defined(__MK66FX1M0__) && !defined(__MK64FX512__)
#include "SoftwareSerial.h"
#endif

#define SENSOR_NONE 0x0000
#define SENSOR_FAS  0x0001
#define SENSOR_FGS  0x0002
#define SENSOR_FLVS 0x0004
#define SENSOR_FVAS 0x0008
#define SENSOR_GPS  0x0010
#define SENSOR_TAS  0x0020
#define SENSOR_TEMS 0x0040
#define SENSOR_RPMS 0x0080

class FrSkyTelemetry
{
  public:
    // Constructor - used to create the telemetry object
    FrSkyTelemetry();
#if defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MKL26Z64__)
    // Serial port identifiers for Teensy 3.0/3.1/3.2/LC boards
    enum SerialId { SERIAL_USB = 0, SERIAL_1 = 1, SERIAL_2 = 2, SERIAL_3 = 3 };
#elif defined(__MK66FX1M0__) || defined(__MK64FX512__)
    // Serial port identifiers for Teensy 3.5/3.6 boards
    enum SerialId { SERIAL_USB = 0, SERIAL_1 = 1, SERIAL_2 = 2, SERIAL_3 = 3, SERIAL_4 = 4 , SERIAL_5 = 5 , SERIAL_6 = 6 };
#else
    // Serial port identifiers for 328P/168 based boards
    enum SerialId { SOFT_SERIAL_PIN_2 = 2, SOFT_SERIAL_PIN_3 = 3, SOFT_SERIAL_PIN_4 = 4, SOFT_SERIAL_PIN_5 = 5, SOFT_SERIAL_PIN_6 = 6, SOFT_SERIAL_PIN_7 = 7,
                     SOFT_SERIAL_PIN_8 = 8, SOFT_SERIAL_PIN_9 = 9, SOFT_SERIAL_PIN_10 = 10, SOFT_SERIAL_PIN_11 = 11, SOFT_SERIAL_PIN_12 = 12 };
#endif
    // Start the telemetry on a given port/pin (use serialId enum to choose, chose the proper one depending on whether you use Teensy od 328P/168 based board)
    void begin(SerialId id);
    // NOTE: the set methods below do not need to be called on every loop - only when data changes
    // Set the FGS sensor data: fuel in percent
    void setFgsData(float fuel);
    // Set the FLVS sensor data: each cell voltage in volts. Skip non-existing cells
    void setFlvsData(float cell1, float cell2 = 0.0, float cell3 = 0.0, float cell4 = 0.0, float cell5 = 0.0, float cell6 = 0.0,
                     float cell7 = 0.0, float cell8 = 0.0, float cell9 = 0.0, float cell10 = 0.0, float cell11 = 0.0, float cell12 = 0.0);
    // Set the FAS sensor data: current in amperes, voltage in volts
    void setFasData(float current, float voltage);
    // Set the FVAS sensor data: altitude in meters (can be negative), vertical speed in m/s (can be nevative, 0.0m/s will be set when skipped)
    void setFvasData(float altitude, float vsi = 0.0);
    // Set the GPS sensor data: lat/lon in degrees decimal (positive for N/E, negative for S/W), alt in meters (can be negative), speed in m/s, course over ground (cog) in degrees 0-359
    //                          subtract 2000 from year, hours in 24h format
    void setGpsData(float lat, float lon, float alt, float speed, float cog, uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second);
    // Set the TAS sensor data: X/Y/Z acceleration in Gs (can be negative)
    void setTasData(float accX, float accY, float accZ);
    // Set the TEMS sensor data: t1/t2 in degrees Celsius (can be negative)
    void setTemsData(float t1, float t2);
    // Set the RPMS sensor data: rpm in rotations per minute. Set number of blades to 2 in your radio
    void setRpmsData(float rpm);
    // Send the telemetry data, needs to be called in every loop (but data will only be sent in defined time periods and only for sensors for which the set method was called at least once)
    void send();

  private:
    uint16_t enabledSensors;
    uint8_t  cellIdx;
    uint32_t frame1Time;
    uint32_t frame2Time;
    uint32_t frame3Time;
    Stream* port;
#if !defined(__MK20DX128__) && !defined(__MK20DX256__) && !defined(__MKL26Z64__) && !defined(__MK66FX1M0__) && !defined(__MK64FX512__)
    SoftwareSerial* softSerial;
#endif
    // FAS sensor
    uint16_t voltageBD;
    uint16_t voltageAD;
    uint16_t current;

    // FGS sensor
    uint16_t fuel;

    // FLVS sensor
    uint16_t cell[12];
    
    // FVAS sensor
    int16_t  altBD;
    uint16_t altAD;
    int16_t  vsi;

    // GPS sensor
    int16_t  latBD;
    uint16_t latAD;
    uint16_t latNS;
    int16_t  lonBD;
    uint16_t lonAD;
    uint16_t lonEW;
    int16_t  gpsAltBD;
    uint16_t gpsAltAD;
    int16_t  speedBD;
    uint16_t speedAD;
    uint16_t cogBD;
    uint16_t cogAD;
    uint16_t year;
    uint16_t dayMonth;
    uint16_t hourMinute;
    uint16_t second;

    // TAS sensor
    int16_t accX;
    int16_t accY;
    int16_t accZ;

    // TEMS sensor
    int16_t t1;
    int16_t t2;

    // RPMS sensor
    uint16_t rpm;

    void sendSeparator();
    void sendByte(uint8_t byte);
    void sendData(uint8_t dataId, uint16_t data, bool bigEndian = false);
    bool sendFgsData();
    bool sendFlvsData();
    bool sendFasData();
    bool sendFvasData();
    bool sendGpsData();
    bool sendDateTimeData();
    bool sendTasData();
    bool sendTemsData();
    bool sendRpmsData();
    void sendFrame1();
    void sendFrame2();
    void sendFrame3();
};

#endif // _FRSKY_TELEMETRY_H_

An example how this lib is used for simulate sevral sensors:

Code:

/*
  FrSky Telemetry library example
  (c) Pawelsky 20170831
  Not for commercial use
 
  Note that you need Teensy 3.x/LC or 328P/168 based (e.g. Pro Mini, Nano, Uno) board and FrSkyTelemetry library for this example to work
*/

#include "FrSkyTelemetry.h"
#if !defined(__MK20DX128__) && !defined(__MK20DX256__) && !defined(__MKL26Z64__) && !defined(__MK66FX1M0__) && !defined(__MK64FX512__)
#include "SoftwareSerial.h"
#endif

FrSkyTelemetry telemetry; // Create telemetry object

void setup()
{
  // Configure the telemetry serial port
#if defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MKL26Z64__) || defined(__MK66FX1M0__) || defined(__MK64FX512__)
  telemetry.begin(FrSkyTelemetry::SERIAL_3);
#else
  telemetry.begin(FrSkyTelemetry::SOFT_SERIAL_PIN_12);
#endif
}

void loop()
{
  // Set current/voltage sensor (FAS) data
  // (set Voltage source to FAS in menu to use this data for battery voltage,
  //  set Current source to FAS in menu to use this data for current readins)
  telemetry.setFasData(25.3,   // Current consumption in amps
                       12.6);  // Battery voltage in volts

  // Set fuel sensor (FGS) data
  telemetry.setFgsData(55.5);  // Fuel level in percent

  // Set LiPo voltage sensor (FLVS) data (we use two sensors to simulate 8S battery
  // (set Voltage source to Cells in menu to use this data for battery voltage)
  telemetry.setFlvsData(4.07, 4.08, 4.09, 4.10, 4.11, 4.12, 4.13, 4.14);  // Cell voltages in volts (cells 1-8). Cells 9-12 are not used in this example

  // Set variometer sensor (FVAS) data
  telemetry.setFvasData(245.5,   // Altitude in m (can be nevative)
                         -3.5);  // Vertical speed in m/s (can be nevative, 0.0m/s will be set when skipped)

  // Set GPS data
  telemetry.setGpsData(48.858289, 2.294502,   // Latitude and longitude in degrees decimal (positive for N/E, negative for S/W)
                       245.5,                 // Altitude in m (can be nevative)
                       100.0,                 // Speed in m/s
                       90.23,                 // Course over ground in degrees
                       14, 9, 14,             // Date (year - 2000, month, day)
                       12, 00, 00);           // Time (hour, minute, second) - will be affected by timezone setings in your radio

  // Set triaxial acceleration sensor (TAS) data
  telemetry.setTasData(17.95,    // x-axis acceleration in g (can be negative)
                       0.0,      // y-axis acceleration in g (can be negative)
                       -17.95);  // z-axis acceleration in g (can be negative)
              
  // Set temperature sensor (TEMS) data
  telemetry.setTemsData(25.6,   // Temperature #1 in degrees Celsuis (can be negative)
                        -7.8);  // Temperature #2 in degrees Celsuis (can be negative)
 
  // Set RPM sensor (RPMS) data
  // (set number of blades to 2 in telemetry menu to get correct rpm value)
  telemetry.setRpmsData(200);  // Rotations per minute

  // Send the telemetry data, note that the data will only be sent for sensors
  // that had their data set at least once. Also it will only be set in defined
  // time intervals, so not necessarily at every call to send() method.
  telemetry.send();
}

airely · Apr 24, 2025

What exactly is this for? I recently installed this same library but it isn’t working on my teensy 4.1 either. I am trying to connect my teensy to the immersion rc ghost jr module smart port so I can get telemetry back to the teensy. Are you doing something similar?

airely · Apr 24, 2025

I saw this forum where the library author posted it. It says it works with teensy 4.x. He listed the updates and said there was an issue using serial 2 and 4 but it had been resolved.

https://www.rcgroups.com/forums/showthread.php?2245978-FrSky-S-Port-telemetry-library-easy-to-use-and-configurable

pierrotm777 · Apr 24, 2025

Yes, but it's a library for the old frsky telemetry named HUB, not S-PORT.

pierrotm777 · Apr 24, 2025

airely said:
I saw this forum where the library author posted it. It says it works with teensy 4.x. He listed the updates and said there was an issue using serial 2 and 4 but it had been resolved.

https://www.rcgroups.com/forums/showthread.php?2245978-FrSky-S-Port-telemetry-library-easy-to-use-and-configurable

Yes, I used it, I have helped for use with the Teensy 4.0, but it's not what I need. I want use the Hub version and this version need to be updated for use with teensy 4.0

airely · Apr 24, 2025

Oh ok, I see! Sorry I’m a complete amateur with this.

I have a question myself then: I used jumpers to connect my immersion rc ghost jr module to the frsky pins and of course the telemetry works perfectly. I used an oscilloscope to check the signal coming in. However, when I connect that same smart port jumper to the teensy, the smart port isn’t sending anything. What am I missing?

I believe there needs to be some “handshake” before the telemetry is sent back but I’m not sure exactly how that works.

pierrotm777 · Apr 24, 2025

airely said:
Oh ok, I see! Sorry I’m a complete amateur with this.

I have a question myself then: I used jumpers to connect my immersion rc ghost jr module to the frsky pins and of course the telemetry works perfectly. I used an oscilloscope to check the signal coming in. However, when I connect that same smart port jumper to the teensy, the smart port isn’t sending anything. What am I missing?

I believe there needs to be some “handshake” before the telemetry is sent back but I’m not sure exactly how that works.

Witch library S-port do you use?

airely · Apr 24, 2025

I am using this library.

https://www.rcgroups.com/forums/showthread.php?2245978-FrSky-S-Port-telemetry-library-easy-to-use-and-configurable

pierrotm777 · Apr 24, 2025

Ok, it's the good lib but just recently updated.
I use it for another project and run well

airely · Apr 24, 2025

And you are able to get telemetry back from the smart port of an external tx? I am using the teensy to send inputs to the module but I want to get the telemetry back

pierrotm777 · Apr 24, 2025

Actually, I build my telemetry with this lib and sent it to my x8r receiver.
But this library can also decode S-port stream. I haven't tried to decode.

el_supremo · Apr 26, 2025

@pierrotm777
I had a look at the library you posted in #1 and have modified it so that it appears to work on a Teensy 4.0 or Teensy 4.1
I tested it on a T4.1 by using Serial2 (instead of Serial3 because it's easier to reach) and looping it back on itself and reading/printing the received data.

Give it a try.

Pete

pierrotm777 · Apr 26, 2025

Whaooo thank you very much for your help.
I can test it only Monday.

el_supremo · Apr 26, 2025

No rush

You're welcome and I hope it works.

Pete

el_supremo · Apr 26, 2025

I had another, closer, look at the link you provided in #8 and the two versions of that library both seem to support T4.0 and T4.1.
Can't you use either of those?

Pete

pierrotm777 · Apr 26, 2025

Yes, S-Port is another frsky protocol and it running very well now with the Teensy.

pierrotm777 · Apr 27, 2025

I am sorry el_supremo but your code running VERY VERY WELL !!

Thanks you again for your job .

pierrotm777 · Apr 27, 2025

el_supremo said:
No rush
You're welcome and I hope it works.

Pete

If you have some time,

, I have a last need, this library for Flysky Ibus protocol.

https://forum.pjrc.com/index.php?threads/adapt-this-other-flysky-ibus-library-to-teensy-family.76875/

Thanks again

Adapt a library to a Teensy 4.0

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