[APRS] Added Mic-E (#430)

jgromes · Aug 20, 2022 · 30cb7c8 · 30cb7c8
1 parent a8c079f
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diff --git a/examples/APRS/APRS_MicE/APRS_MicE.ino b/examples/APRS/APRS_MicE/APRS_MicE.ino
@@ -0,0 +1,111 @@
+/*
+   RadioLib APRS Mic-E Example
+
+   This example sends APRS position reports 
+   encoded in the Mic-E format using SX1278's
+   FSK modem. The data is modulated as AFSK
+   at 1200 baud using Bell 202 tones.
+
+   DO NOT transmit in APRS bands unless
+   you have a ham radio license!
+
+   Other modules that can be used for APRS:
+    - SX127x/RFM9x
+    - RF69
+    - SX1231
+    - CC1101
+    - nRF24
+    - Si443x/RFM2x
+
+   For default module settings, see the wiki page
+   https://github.com/jgromes/RadioLib/wiki/Default-configuration
+
+   For full API reference, see the GitHub Pages
+   https://jgromes.github.io/RadioLib/
+*/
+
+// include the library
+#include <RadioLib.h>
+
+// SX1278 has the following connections:
+// NSS pin:   10
+// DIO0 pin:  2
+// RESET pin: 9
+// DIO1 pin:  3
+SX1278 radio = new Module(10, 2, 9, 3);
+
+// or using RadioShield
+// https://github.com/jgromes/RadioShield
+//SX1278 radio = RadioShield.ModuleA;
+
+// create AFSK client instance using the FSK module
+// pin 5 is connected to SX1278 DIO2
+AFSKClient audio(&radio, 5);
+
+// create AX.25 client instance using the AFSK instance
+AX25Client ax25(&audio);
+
+// create APRS client isntance using the AX.25 client
+APRSClient aprs(&ax25);
+
+void setup() {
+  Serial.begin(9600);
+
+  // initialize SX1278
+  // NOTE: moved to ISM band on purpose
+  //       DO NOT transmit in APRS bands without ham radio license!
+  Serial.print(F("[SX1278] Initializing ... "));
+  int state = radio.beginFSK();
+
+  // when using one of the non-LoRa modules for AX.25
+  // (RF69, CC1101, Si4432 etc.), use the basic begin() method
+  // int state = radio.begin();
+
+  if(state == RADIOLIB_ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+
+  // initialize AX.25 client
+  Serial.print(F("[AX.25] Initializing ... "));
+  // source station callsign:     "N7LEM"
+  // source station SSID:         0
+  // preamble length:             8 bytes
+  state = ax25.begin("N7LEM");
+  if(state == RADIOLIB_ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+
+  // initialize APRS client
+  Serial.print(F("[APRS] Initializing ... "));
+  // symbol:                      '>' (car)
+  state = aprs.begin('>');
+  if(state == RADIOLIB_ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+    while(true);
+  }
+}
+
+void loop() {
+  Serial.print(F("[APRS] Sending Mic-E position ... "));
+  int state = aprs.sendMicE(49.1945, 16.6000, 120, 10, RADIOLIB_APRS_MIC_E_TYPE_EN_ROUTE);
+  if(state == RADIOLIB_ERR_NONE) {
+    Serial.println(F("success!"));
+  } else {
+    Serial.print(F("failed, code "));
+    Serial.println(state);
+  }
+
+  // wait one minute before transmitting again
+  delay(60000);
+}
diff --git a/keywords.txt b/keywords.txt
@@ -150,6 +150,8 @@ randomByte	KEYWORD2
 getPacketLength	KEYWORD2
 setFifoEmptyAction	KEYWORD2
 clearFifoEmptyAction	KEYWORD2
+setFifoFullAction	KEYWORD2
+clearFifoFullAction	KEYWORD2
 fifoAdd	KEYWORD2
 fifoGet	KEYWORD2
 
@@ -234,6 +236,7 @@ noTone	KEYWORD2
 
 # APRS
 sendPosition	KEYWORD2
+sendMicE	KEYWORD2
 
 #######################################
 # Constants (LITERAL1)
@@ -291,6 +294,12 @@ RADIOLIB_ERR_INVALID_RX_BANDWIDTH	LITERAL1
 RADIOLIB_ERR_INVALID_SYNC_WORD	LITERAL1
 RADIOLIB_ERR_INVALID_DATA_SHAPING	LITERAL1
 RADIOLIB_ERR_INVALID_MODULATION	LITERAL1
+RADIOLIB_ERR_INVALID_OOK_RSSI_PEAK_TYPE	LITERAL1
+
+RADIOLIB_ERR_INVALID_SYMBOL	LITERAL1
+RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY	LITERAL1
+RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY_LENGTH	LITERAL1
+RADIOLIB_ERR_MIC_E_TELEMETRY_STATUS	LITERAL1
 
 RADIOLIB_ASCII	LITERAL1
 RADIOLIB_ASCII_EXTENDED	LITERAL1

diff --git a/src/TypeDef.h b/src/TypeDef.h
@@ -262,6 +262,21 @@
 */
 #define RADIOLIB_ERR_INVALID_SYMBOL                            (-201)
 
+/*!
+  \brief Mic-E Telemetry is invalid.
+*/
+#define RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY                   (-202)
+
+/*!
+  \brief Mic-E Telemetry length is invalid (only 0, 2 or 5 is allowed).
+*/
+#define RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY_LENGTH            (-203)
+
+/*!
+  \brief Mic-E message cannot contaion both telemetry and status text.
+*/
+#define RADIOLIB_ERR_MIC_E_TELEMETRY_STATUS                    (-204)
+
 // RTTY status codes
 
 /*!

diff --git a/src/protocols/APRS/APRS.cpp b/src/protocols/APRS/APRS.cpp
@@ -54,6 +54,166 @@ int16_t APRSClient::sendPosition(char* destCallsign, uint8_t destSSID, char* lat
   return(state);
 }
 
+int16_t APRSClient::sendMicE(float lat, float lon, uint16_t heading, uint16_t speed, uint8_t type, uint8_t* telem, size_t telemLen, char* grid, char* status, int32_t alt) {
+  // sanity checks first
+  if(((telemLen == 0) && (telem != NULL)) || ((telemLen != 0) && (telem == NULL))) {
+    return(RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY);
+  }
+
+  if((telemLen != 0) && (telemLen != 2) && (telemLen != 5)) {
+    return(RADIOLIB_ERR_INVALID_MIC_E_TELEMETRY_LENGTH);
+  }
+
+  if((telemLen > 0) && ((grid != NULL) || (status != NULL) || (alt != RADIOLIB_APRS_MIC_E_ALTITUDE_UNUSED))) {
+    // can't have both telemetry and status
+    return(RADIOLIB_ERR_MIC_E_TELEMETRY_STATUS);
+  }
+
+  // prepare buffers
+  char destCallsign[7];
+  #if !defined(RADIOLIB_STATIC_ONLY)
+    size_t infoLen = 10;
+    if(telemLen > 0) {
+      infoLen += 1 + telemLen;
+    } else {
+      if(grid != NULL) {
+        infoLen += strlen(grid) + 2;
+      }
+      if(status != NULL) {
+        infoLen += strlen(status);
+      }
+      if(alt > RADIOLIB_APRS_MIC_E_ALTITUDE_UNUSED) {
+        infoLen += 4;
+      }
+    }
+    char* info = new char[infoLen];
+  #else
+    char info[RADIOLIB_STATIC_ARRAY_SIZE];
+  #endif
+  size_t infoPos = 0;
+
+  // the following is based on APRS Mic-E implementation by https://github.com/omegat
+  // as discussed in https://github.com/jgromes/RadioLib/issues/430
+
+  // latitude first, because that is in the destination field
+  float lat_abs = abs(lat);
+  int lat_deg = (int)lat_abs;
+  int lat_min = (lat_abs - (float)lat_deg) * 60.0f;
+  int lat_hun = (((lat_abs - (float)lat_deg) * 60.0f) - lat_min) * 100.0f;
+  destCallsign[0] = lat_deg/10;
+  destCallsign[1] = lat_deg%10;
+  destCallsign[2] = lat_min/10;
+  destCallsign[3] = lat_min%10;
+  destCallsign[4] = lat_hun/10;
+  destCallsign[5] = lat_hun%10;
+
+  // next, add the extra bits
+  if(type & 0x04) { destCallsign[0] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  if(type & 0x02) { destCallsign[1] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  if(type & 0x01) { destCallsign[2] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  if(lat >= 0) { destCallsign[3] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  if(lon >= 100 || lon <= -100) { destCallsign[4] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  if(lon < 0) { destCallsign[5] += RADIOLIB_APRS_MIC_E_DEST_BIT_OFFSET; }
+  destCallsign[6] = '\0';
+
+  // now convert to Mic-E characters to get the "callsign"
+  for(uint8_t i = 0; i < 6; i++) {
+    if(destCallsign[i] <= 9) {
+      destCallsign[i] += '0';
+    } else {
+      destCallsign[i] += ('A' - 10);
+    }
+  }
+
+  // setup the information field
+  info[infoPos++] = RADIOLIB_APRS_MIC_E_GPS_DATA_CURRENT;
+
+  // encode the longtitude
+  float lon_abs = abs(lon);
+  int32_t lon_deg = (int32_t)lon_abs;
+  int32_t lon_min = (lon_abs - (float)lon_deg) * 60.0f;
+  int32_t lon_hun = (((lon_abs - (float)lon_deg) * 60.0f) - lon_min) * 100.0f;
+
+  if(lon_deg <= 9) {
+    info[infoPos++] = lon_deg + 118;
+  } else if(lon_deg <= 99) {
+    info[infoPos++] = lon_deg + 28;
+  } else if(lon_deg <= 109) {
+    info[infoPos++] = lon_deg + 8;
+  } else {
+    info[infoPos++] = lon_deg - 72;
+  }
+
+  if(lon_min <= 9){
+    info[infoPos++] = lon_min + 88;
+  } else {
+    info[infoPos++] = lon_min + 28;
+  }
+
+  info[infoPos++] = lon_hun + 28;
+
+  // now the speed and heading - this gets really weird
+  int32_t speed_hun_ten = speed/10;
+  int32_t speed_uni = speed%10;
+  int32_t head_hun = heading/100;
+  int32_t head_ten_uni = heading%100;
+
+  if(speed <= 199) {
+    info[infoPos++] = speed_hun_ten + 'l';
+  } else {
+    info[infoPos++] = speed_hun_ten + '0';
+  }
+
+  info[infoPos++] = speed_uni*10 + head_hun + 32;
+  info[infoPos++] = head_ten_uni + 28;
+  info[infoPos++] = _symbol;
+  info[infoPos++] = _table;
+
+  // onto the optional stuff - check telemetry first
+  if(telemLen > 0) {
+    if(telemLen == 2) {
+      info[infoPos++] = RADIOLIB_APRS_MIC_E_TELEMETRY_LEN_2;
+    } else {
+      info[infoPos++] = RADIOLIB_APRS_MIC_E_TELEMETRY_LEN_5;
+    }
+    for(uint8_t i = 0; i < telemLen; i++) {
+      sprintf(&(info[infoPos]), "%02X", telem[i]);
+      infoPos += 2;
+    }
+
+  } else {
+    if(grid != NULL) {
+      memcpy(&(info[infoPos]), grid, strlen(grid));
+      infoPos += strlen(grid);
+      info[infoPos++] = '/';
+      info[infoPos++] = 'G';
+    }
+    if(status != NULL) {
+      info[infoPos++] = ' ';
+      memcpy(&(info[infoPos]), status, strlen(status));
+      infoPos += strlen(status);
+    }
+    if(alt > RADIOLIB_APRS_MIC_E_ALTITUDE_UNUSED) {
+      // altitude is offset by -10 km
+      int32_t alt_val = alt + 10000;
+
+      // ... and encoded in base 91 for some reason
+      info[infoPos++] = (alt_val / 8281) + 33;
+      info[infoPos++] = ((alt_val % 8281) / 91) + 33;
+      info[infoPos++] = ((alt_val % 8281) % 91) + 33;
+      info[infoPos++] = '}';
+    }
+  }
+  info[infoPos++] = '\0';
+
+  // send the frame
+  int16_t state = sendFrame(destCallsign, 0, info);
+  #if !defined(RADIOLIB_STATIC_ONLY)
+    delete[] info;
+  #endif
+  return(state);
+}
+
 int16_t APRSClient::sendFrame(char* destCallsign, uint8_t destSSID, char* info) {
   // get AX.25 callsign
   char srcCallsign[RADIOLIB_AX25_MAX_CALLSIGN_LEN + 1];