Add detailed sender ACK RX diagnostics with reject context

include/lora_transport.h

@@ -32,6 +32,7 @@ void lora_init();
 bool lora_send(const LoraPacket &pkt);
 bool lora_receive(LoraPacket &pkt, uint32_t timeout_ms);
 RxRejectReason lora_get_last_rx_reject_reason();
+bool lora_get_last_rx_signal(int16_t &rssi_dbm, float &snr_db);
 void lora_idle();
 void lora_sleep();
 void lora_receive_continuous();

src/lora_transport.cpp

@@ -5,6 +5,9 @@
 
 static RxRejectReason g_last_rx_reject_reason = RxRejectReason::None;
 static uint32_t g_last_rx_reject_log_ms = 0;
+static bool g_last_rx_signal_valid = false;
+static int16_t g_last_rx_rssi_dbm = 0;
+static float g_last_rx_snr_db = 0.0f;
 
 static void note_reject(RxRejectReason reason) {
   g_last_rx_reject_reason = reason;
@@ -23,6 +26,15 @@ RxRejectReason lora_get_last_rx_reject_reason() {
   return reason;
 }
 
+bool lora_get_last_rx_signal(int16_t &rssi_dbm, float &snr_db) {
+  if (!g_last_rx_signal_valid) {
+    return false;
+  }
+  rssi_dbm = g_last_rx_rssi_dbm;
+  snr_db = g_last_rx_snr_db;
+  return true;
+}
+
 static uint16_t crc16_ccitt(const uint8_t *data, size_t len) {
   uint16_t crc = 0xFFFF;
   for (size_t i = 0; i < len; ++i) {
@@ -109,6 +121,10 @@ bool lora_receive(LoraPacket &pkt, uint32_t timeout_ms) {
   while (true) {
     int packet_size = LoRa.parsePacket();
     if (packet_size > 0) {
+      g_last_rx_rssi_dbm = static_cast<int16_t>(LoRa.packetRssi());
+      g_last_rx_snr_db = LoRa.packetSnr();
+      g_last_rx_signal_valid = true;
+
       if (packet_size < 5) {
         while (LoRa.available()) {
           LoRa.read();
@@ -148,8 +164,8 @@ bool lora_receive(LoraPacket &pkt, uint32_t timeout_ms) {
         return false;
       }
       memcpy(pkt.payload, &buffer[3], pkt.payload_len);
-      pkt.rssi_dbm = static_cast<int16_t>(LoRa.packetRssi());
+      pkt.rssi_dbm = g_last_rx_rssi_dbm;
-      pkt.snr_db = LoRa.packetSnr();
+      pkt.snr_db = g_last_rx_snr_db;
       return true;
     }
 

src/main.cpp

@@ -871,11 +871,40 @@ static void sender_loop() {
       g_sender_rx_window_ms += rx_elapsed;
     }
     if (!got_ack) {
-      sender_note_rx_reject(lora_get_last_rx_reject_reason(), "ack");
+      RxRejectReason reason = lora_get_last_rx_reject_reason();
+      sender_note_rx_reject(reason, "ack");
+      if (SERIAL_DEBUG_MODE) {
+        int16_t rssi_dbm = 0;
+        float snr_db = 0.0f;
+        bool has_signal = lora_get_last_rx_signal(rssi_dbm, snr_db);
+        const char *reason_text = reason == RxRejectReason::None ? "timeout" : rx_reject_reason_text(reason);
+        if (has_signal) {
+          serial_debug_printf("ack: rx miss reason=%s rssi=%d snr=%.1f",
+                              reason_text,
+                              static_cast<int>(rssi_dbm),
+                              static_cast<double>(snr_db));
+        } else {
+          serial_debug_printf("ack: rx miss reason=%s", reason_text);
+        }
+      }
     } else if (ack_pkt.msg_kind != LoraMsgKind::AckDown) {
       sender_note_rx_reject(RxRejectReason::InvalidMsgKind, "ack");
+      if (SERIAL_DEBUG_MODE) {
+        uint16_t ack_id = ack_pkt.payload_len >= 3 ? read_u16_be(&ack_pkt.payload[1]) : 0;
+        serial_debug_printf("ack: reject msg_kind=%u payload_len=%u ack_id=%u",
+                            static_cast<unsigned>(ack_pkt.msg_kind),
+                            static_cast<unsigned>(ack_pkt.payload_len),
+                            ack_id);
+      }
     } else if (ack_pkt.payload_len < LORA_ACK_DOWN_PAYLOAD_LEN) {
       sender_note_rx_reject(RxRejectReason::LengthMismatch, "ack");
+      if (SERIAL_DEBUG_MODE) {
+        uint16_t ack_id = ack_pkt.payload_len >= 3 ? read_u16_be(&ack_pkt.payload[1]) : 0;
+        serial_debug_printf("ack: reject msg_kind=%u payload_len=%u ack_id=%u",
+                            static_cast<unsigned>(ack_pkt.msg_kind),
+                            static_cast<unsigned>(ack_pkt.payload_len),
+                            ack_id);
+      }
     } else {
       uint8_t time_valid = ack_pkt.payload[0] & 0x01;
       uint16_t ack_id = read_u16_be(&ack_pkt.payload[1]);
@@ -897,6 +926,12 @@ static void sender_loop() {
       } else {
         if (ack_id != g_last_sent_batch_id) {
           sender_note_rx_reject(RxRejectReason::BatchIdMismatch, "ack");
+          if (SERIAL_DEBUG_MODE) {
+            serial_debug_printf("ack: reject msg_kind=%u payload_len=%u ack_id=%u",
+                                static_cast<unsigned>(ack_pkt.msg_kind),
+                                static_cast<unsigned>(ack_pkt.payload_len),
+                                ack_id);
+          }
         }
       }
     }