Configurable CRC

lib/comms/comms.cpp

@@ -184,19 +184,18 @@ String _scan_str(ScanTask &);
 String _scan_result_str(ScanTaskResult &);
 String _wrap_str(String);
 
-#define POLY 0x1021
-uint16_t crc16(String v, uint16_t c)
+uint16_t crc16(uint16_t poly, uint16_t c, size_t sz, uint8_t *v)
 {
     c ^= 0xffff;
-    for (int i = 0; i < v.length(); i++)
+    for (int i = 0; i < sz; i++)
     {
-        uint16_t ch = v.charAt(i);
+        uint16_t ch = v[i];
         c = c ^ (ch << 8);
         for (int j = 0; j < 8; j++)
         {
             if (c & 0x8000)
             {
-                c = (c << 1) ^ POLY;
+                c = (c << 1) ^ poly;
             }
             else
             {
@@ -208,6 +207,12 @@ uint16_t crc16(String v, uint16_t c)
     return c ^ 0xffff;
 }
 
+#define POLY 0x1021
+uint16_t crc16(String v, uint16_t c)
+{
+    return crc16(POLY, c, v.length(), (uint8_t *)v.c_str());
+}
+
 void ReadlineComms::_onReceive()
 {
     while (serial.available() > 0)

lib/comms/comms.h

@@ -90,6 +90,7 @@ struct Endpoint
 {
     union
     {
+
         struct
         {
             uint8_t loop : 1, // self
@@ -158,14 +159,35 @@ extern Comms *Comms0;
 
 extern Comms *Comms1;
 
+struct LoRaStats
+{
+    uint64_t t0;
+    int64_t rssi_60;
+    int64_t snr_60;
+
+    int16_t last_rssi;
+    int16_t last_snr;
+
+    int64_t messages_60;
+    int64_t errors_60;
+
+    LoRaStats()
+        : t0(0), rssi_60(0), snr_60(0), last_rssi(0), last_snr(0), messages_60(0),
+          errors_60(0)
+    {
+    }
+};
+
 struct RadioComms
 {
     String name;
     RADIO_TYPE &radio;
     LoRaConfig &loraCfg;
 
+    LoRaStats stats;
+
     RadioComms(String name, RADIO_TYPE &radio, LoRaConfig &cfg)
-        : name(name), radio(radio), loraCfg(cfg)
+        : name(name), radio(radio), loraCfg(cfg), stats()
     {
     }
 
@@ -176,6 +198,15 @@ struct RadioComms
     Message *receive(uint16_t timeout_ms);
 };
 
+uint16_t crc16(uint16_t poly, uint16_t c, size_t sz, uint8_t *v);
+
+/*
+ * Given halflife (i.e. time it takes the accumulator to decay to 50%), compute
+ * the updated cumulate at new time. That is, acc_now = decay(acc_t, inc).
+ */
+int64_t updateExpDecay(uint16_t halflife, int64_t acc, uint64_t t, uint64_t now,
+                       int64_t inc);
+
 extern RadioComms *RxComms;
 extern RadioComms *TxComms;
 

lib/comms/radio_comms.cpp

@@ -188,6 +188,11 @@ int16_t RadioComms::send(Message &m)
     size_t p = MAX_MSG;
     uint8_t *msg = NULL;
 
+    if (loraCfg.crc)
+    {
+        p -= 2;
+    }
+
     if (m.type == SCAN_RESULT)
     {
         msg = _serialize_scan_result(m, p, msg_buf);
@@ -207,6 +212,13 @@ int16_t RadioComms::send(Message &m)
         return RADIOLIB_ERR_INVALID_FUNCTION;
     }
 
+    if (loraCfg.crc)
+    {
+        uint16_t c = loraCfg.crc_seed ^ 0xffff;
+        c = crc16(loraCfg.crc_poly, c, p, msg);
+        _write(msg, MAX_MSG, p, (uint8_t *)&c, 2);
+    }
+
     int16_t status = radio.transmit(msg, p);
 
     if (msg != msg_buf)
@@ -385,7 +397,7 @@ Message *RadioComms::receive(uint16_t timeout_ms)
     radio.clearDio1Action();
 
     packetRssi = radio.getRSSI(true);
-    Serial.println("LORA_RSSI: " + String(packetRssi));
+    // Serial.println("LORA_RSSI:" + String(packetRssi));
     size_t len = radio.getPacketLength(true);
     uint8_t *packet = msg;
 

lib/config/config.cpp

@@ -189,7 +189,9 @@ String loraConfigToStr(LoRaConfig *cfg)
            String(",tx_power:") + String(cfg->tx_power) + String(",preamble_len:") +
            String(cfg->preamble_len) + String(",sync_word:") +
            String(cfg->sync_word, 16) + String(",crc:") + String(cfg->crc ? "1" : "0") +
-           String(",implicit_header:") + String(cfg->implicit_header);
+           String(",crc_seed:") + String(cfg->crc_seed, 16) + String(",crc_poly:") +
+           String(cfg->crc_poly, 16) + String(",implicit_header:") +
+           String(cfg->implicit_header);
 }
 
 String detectionStrategyToStr(Config &c)
@@ -356,6 +358,8 @@ LoRaConfig *configureLora(String cfg)
         preamble_len : 8,
         sync_word : 0x1e,
         crc : false,
+        crc_seed : 0,
+        crc_poly : 0x1021,
         implicit_header : 0
     });
 
@@ -383,6 +387,18 @@ LoRaConfig *configureLora(String cfg)
             continue;
         }
 
+        if (k.equalsIgnoreCase("crc_seed"))
+        {
+            lora->crc_seed = (uint16_t)fromHex(param);
+            continue;
+        }
+
+        if (k.equalsIgnoreCase("crc_poly"))
+        {
+            lora->crc_poly = (uint16_t)fromHex(param);
+            continue;
+        }
+
         if (k.equalsIgnoreCase("freq"))
         {
             lora->freq = param.toFloat();

lib/config/config.h

@@ -46,6 +46,8 @@ struct LoRaConfig
     uint16_t preamble_len;
     uint8_t sync_word;
     bool crc;
+    uint16_t crc_seed;
+    uint16_t crc_poly;
     uint8_t implicit_header;
 };