Payload Format

Overview

Payload Types

Port	Type	Description
100	Welcome	Device type, firmware version, hardware ID. Sent once after reboot
101	Status	Battery level, buffer status information and sensor data
103	Location	GPS location information and time
150-200	Proprietary	Refer to application-specific documentation
212	Git	Git revision. Sent once after reboot.
220	Configuration	Device configuration using AT command downlinks

Number Encoding

Signed integers use two’s complement for encoding.

Important

Unless otherwise noted, payloads will use big endian data encoding.

Payload Description

Welcome Message

Contains information about the device and firmware. The welcome message is sent only once after reboot.

Byte	Size	Description	Format
0	1	Device type (Tracker=1)	enum
1	1	Device sub-type (miro Nomad=1, miro Cargo=3)	enum
2-5	4	Firmware version hash	uint32
6	1	Reset source (1=WU, 2=PIN, 3=LPW, 4=SW, 5=POR, 6=IWDG, 7=WWDG)	enum
7-14	8	Hardware ID	uint64_t

Status Message

Contains general status information and environmental sensor data.

Byte	Size	Description	Format
0-7	8	System time (ms since reset)	uint64_t, ms
8-11	4	UTC Date	uint32, DDMMYY
12-15	4	UTC Time	uint32, HHMMSS
16-17	2	Buffer level (STA)	uint16
18-19	2	Buffer level (GPS)	uint16
20-21	2	Buffer level (ACC)	uint16
22-23	2	Buffer level (LOG)	uint16
24-25	2	Temperature	int16, 0.1 °C
26-27	2	Pressure	uint16, 0.1 hPa
28-29	2	Orientation X	int16, mG
30-31	2	Orientation Y	int16, mG
32-33	2	Orientation Z	int16, mG
34-35	2	Battery voltage	uint16, mV
36	1	LoRaWAN battery level (1 to 254)	uint8
37	1	Last TTF (time to fix)	uint8, s
38-39	2	NMEA sentences checksum OK	uint16
40-41	2	NMEA sentences checksum fail	uint16
42-43	2	Total GPS signal to noise (0-99 for each satellite)	uint16, C/n0 [dBHz]
44	1	GPS satellite count Navstar	uint8
45	1	GPS satellite count Glonass	uint8
46	1	GPS satellite count Galileo	uint8
47	1	GPS satellite count Beidou	uint8
48-49	2	GPS dilution of precision	uint16, cm

Location Message

Contains GPS time and location information. If the payload is all zeros, the miro Cargo could not acquire a GPS fix.

Byte	Size	Description	Format
0-3	4	UTC Date	uint32, DDMMYY
4-7	4	UTC Time	uint32, HHMMSS
8-11	4	Latitude	int32, 1/100'000 deg
12-15	4	Longitude	int32, 1/100'000 deg
16-19	4	Altitude	int32, 1/100 m

Git Revision

Contains the Git revision of the firmware build. The Git message is sent only once after reboot.

Byte	Size	Description	Format
0-19	20	Git Revision	binary/hex

Configuration commands and responses

Configuration downlink commands and responses are sent as plain text. Note that commands need to be zero-terminated. Refer to settings documentation for more information.

Byte	Size	Description	Format
0-(n-1)	n	AT command	ASCII
n	1	zero-termination (0x00)	char

Byte	Size	Description	Format
0-(n-1)	n	Reply to previous AT command	ASCII
n	1	zero-termination (0x00)	char

JavaScript Decoder

For an easy start using miro Cargo on TTN or TTI you can make use of the following JavaScript decoder template.

function decodeUplink(input) {

  var bytes = input.bytes;
  var port = input.fPort;
  var decoded = {};
  var warnings = [];
  var errors = [];

  if (port === 100) {
    // WELCOME MESSAGE
    // Returns device type and firmware version

    switch (bytes[1]) {
      case 1:
          decoded.deviceType = 'miro Nomad';
          break;
      case 3:
          decoded.deviceType = 'miro Cargo';
          break;
      default:
          decoded.deviceType = 'unknown';
          break;
    }

    decoded.firmware = 'v' + bytes[2].toString() + '.' + bytes[3].toString() + '.' + (bytes[4] * 256 + bytes[5]).toString();
  }

  if (port === 212) {
    // GIT REVISION
    // Returns base64-encoded HEX string of firmware GIT revision

    decoded.git_revision = toHexString(bytes);
  }

  if (port === 220) {
    // AT COMMAND RESPONSE
    // Returns base64-encoded ASCII string of AT command response

    decoded.at_reply = bin2String(bytes);
}

  if (port === 101) {
    // STATUS MESSAGE
    // Returns status information
    // Note: Not all fields are taken into account here

    var system_time_ms = (bytes[0] << 56 | bytes[1] << 48 | bytes[2] << 40 | bytes[3] << 32 | bytes[4] << 24 | bytes[5] << 16 | bytes[6] << 8 | bytes[7]) >>> 0;
    var temperature = (bytes[24] << 8 | bytes[25]) >>> 0;
    var pressure = (bytes[26] << 8 | bytes[27]) >>> 0;
    var x = (bytes[28] << 8 | bytes[29]) >>> 0;
    var y = (bytes[30] << 8 | bytes[31]) >>> 0;
    var z = (bytes[32] << 8 | bytes[33]) >>> 0;
    var battery_mv = (bytes[34] << 8 | bytes[35]) >>> 0;

    var dat = (bytes[8] << 24 | bytes[9] << 16 | bytes[10] << 8 | bytes[11]) >>> 0;
    var tim = (bytes[12] << 24 | bytes[13] << 16 | bytes[14] << 8 | bytes[15]) >>> 0;

    // Conversion to signed integer (2's complement)
    if (temperature > 0x7FFF) {
      temperature = -(0xFFFF - temperature + 1);
    }
    if (x > 0x7FFF) {
      x = -(0xFFFF - x + 1);
    }
    if (y > 0x7FFF) {
      y = -(0xFFFF - y + 1);
    }
    if (z > 0x7FFF) {
      z = -(0xFFFF - z + 1);
    }

    decoded.battery_lorawan = bytes[36];
    decoded.gps_ttf_s = bytes[37];
    decoded.gps_signal = bytes[42];

    decoded.battery_v = battery_mv / 1000.0;
    decoded.system_time_s = system_time_ms / 1000.0;
    decoded.temperature_deg = temperature / 10.0;
    decoded.pressure_hpa = pressure / 1.0;
    decoded.orientation_x_g = x / 1000.0;
    decoded.orientation_y_g = y / 1000.0;
    decoded.orientation_z_g = z / 1000.0;

    decoded.date_yymmdd = dat;
    decoded.time_hhmmss = tim;
  }

  if (port === 103) {
    // LOCATION MESSAGE
    // Returns date and time as DDMMYY and HHMMSS
    // Returns latitude, longitude and altitude as float

    var dat = (bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3]) >>> 0;
    var tim = (bytes[4] << 24 | bytes[5] << 16 | bytes[6] << 8 | bytes[7]) >>> 0;
    var lat = (bytes[8] << 24 | bytes[9] << 16 | bytes[10] << 8 | bytes[11]) >>> 0;
    var lon = (bytes[12] << 24 | bytes[13] << 16 | bytes[14] << 8 | bytes[15]) >>> 0;
    var alt = (bytes[16] << 24 | bytes[17] << 16 | bytes[18] << 8 | bytes[19]) >>> 0;

    // Conversion to signed integer (2's complement)
    if (lat > 0x7FFFFFFF) {
      lat = -(0xFFFFFFFF - lat + 1);
    }
    if (lon > 0x7FFFFFFF) {
      lon = -(0xFFFFFFFF - lon + 1);
    }
    if (alt > 0x7FFFFFFF) {
      alt = -(0xFFFFFFFF - alt + 1);
    }

    if ((lat != 0) && (lon != 0)) {
      decoded.gps_dat = dat;
      decoded.gps_tim = tim;
      decoded.gps_lat = (lat / 100000.0);
      decoded.gps_lon = (lon / 100000.0);
      decoded.gps_alt = (alt / 100.0);
      decoded.unixtime_ms = getTimestamp(dat, tim);
    } else {
      warnings.push('No GPS fix, empty location message, ');
    }
  }

  function toHexString(byteArray) {
    return Array.from(byteArray, function(byte) {
      return ('0' + (byte & 0xFF).toString(16)).slice(-2);
    }).join('')
  }

  function bin2String(array) {
    return String.fromCharCode.apply(String, array);
  }

  function getTimestamp(ddmmyy, hhmmss) {
    day = parseInt(ddmmyy / 10000, 10);
    month = parseInt(ddmmyy / 100 - day * 100, 10);
    year = parseInt(ddmmyy - month * 100 - day * 10000 + 2000, 10);
    hour = parseInt(hhmmss / 10000, 10);
    minute = parseInt(hhmmss / 100 - hour * 100, 10);
    second = parseInt(hhmmss - minute * 100 - hour * 10000, 10);

    var date = new Date(year, month - 1, day, hour, minute, second);
    return date.valueOf();
  }

  return {
    data: decoded,
    warnings: warnings,
    errors: errors
  };
}