From 79ef74ea8def0195ddbe340441fec7ce5c943051 Mon Sep 17 00:00:00 2001
From: taco <taco@sly.nu>
Date: Fri, 17 Jul 2026 21:33:57 +1000
Subject: [PATCH] add IRQ timeout logic for SX1262

---
 src/helpers/radiolib/CustomSX1262.h        | 51 +++++++++++++++++++---
 src/helpers/radiolib/CustomSX1262Wrapper.h |  1 +
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/src/helpers/radiolib/CustomSX1262.h b/src/helpers/radiolib/CustomSX1262.h
index ca62fc26a..284b79c02 100644
--- a/src/helpers/radiolib/CustomSX1262.h
+++ b/src/helpers/radiolib/CustomSX1262.h
@@ -3,10 +3,12 @@
 #include <RadioLib.h>
 #include "MeshCore.h"
 
-#define SX126X_IRQ_HEADER_VALID                0b0000010000  //  4     4     valid LoRa header received
-#define SX126X_IRQ_PREAMBLE_DETECTED           0x04
-
 class CustomSX1262 : public SX1262 {
+  uint32_t _preambleMillis = 66;
+  uint32_t _maxPayloadMillis = 3934;
+  uint32_t _activityAt = 0;
+  bool _headerSeen = false;
+
   public:
     CustomSX1262(Module *mod) : SX1262(mod) { }
 
@@ -99,9 +101,46 @@ class CustomSX1262 : public SX1262 {
     }
 
     bool isReceiving() {
-      uint16_t irq = getIrqFlags();
-      bool detected = (irq & SX126X_IRQ_HEADER_VALID) || (irq & SX126X_IRQ_PREAMBLE_DETECTED);
-      return detected;
+      uint32_t irq = getIrqFlags();
+      bool preamble = irq & RADIOLIB_SX126X_IRQ_PREAMBLE_DETECTED; // bit 2
+      bool header   = irq & RADIOLIB_SX126X_IRQ_HEADER_VALID;      // bit 4
+      bool hdrErr   = irq & RADIOLIB_SX126X_IRQ_HEADER_ERR;        // bit 5
+      uint32_t now  = millis();
+      if (hdrErr) {
+        clearIrqFlags(RADIOLIB_SX126X_IRQ_PREAMBLE_DETECTED | RADIOLIB_SX126X_IRQ_HEADER_VALID | RADIOLIB_SX126X_IRQ_HEADER_ERR | RADIOLIB_SX126X_IRQ_SYNC_WORD_VALID);
+        _activityAt = 0;
+        _headerSeen = false;
+        return false;
+      }
+      if (header) {
+        if (!_headerSeen) { _headerSeen = true; _activityAt = now; };
+        if (now - _activityAt > _maxPayloadMillis) {
+          MESH_DEBUG_PRINTLN("Clearing header IRQ after %ums", _maxPayloadMillis);
+          clearIrqFlags(RADIOLIB_SX126X_IRQ_PREAMBLE_DETECTED | RADIOLIB_SX126X_IRQ_HEADER_VALID | RADIOLIB_SX126X_IRQ_HEADER_ERR | RADIOLIB_SX126X_IRQ_SYNC_WORD_VALID);
+          _activityAt = 0; _headerSeen = false;
+          return false;
+        }
+        return true;
+      }
+      if (preamble) {
+        if (_activityAt == 0) _activityAt = now;
+        if (now - _activityAt > _preambleMillis) {
+          clearIrqStatus(RADIOLIB_IRQ_PREAMBLE_DETECTED);
+          _activityAt = 0;
+          MESH_DEBUG_PRINTLN("Clearing preamble IRQ after %ums", _preambleMillis);
+
+          return false;
+        }
+        return true;
+      }
+      _activityAt = 0; _headerSeen = false;
+      return false;
+    }
+
+    PacketMillis setMaxPacketMillis(PacketMillis maxPacketMillis) {
+      MESH_DEBUG_PRINTLN("Setting _preambleMillis=%u, _maxPacketMillis=%u", maxPacketMillis.preambleMillis, maxPacketMillis.payloadMillis);
+      _preambleMillis = maxPacketMillis.preambleMillis;
+      _maxPayloadMillis = maxPacketMillis.payloadMillis;
     }
 
     bool getRxBoostedGainMode() {
diff --git a/src/helpers/radiolib/CustomSX1262Wrapper.h b/src/helpers/radiolib/CustomSX1262Wrapper.h
index 1d103f579..45af4cb4b 100644
--- a/src/helpers/radiolib/CustomSX1262Wrapper.h
+++ b/src/helpers/radiolib/CustomSX1262Wrapper.h
@@ -18,6 +18,7 @@ public:
     ((CustomSX1262 *)_radio)->setBandwidth(bw);
     ((CustomSX1262 *)_radio)->setCodingRate(cr);
     updatePreamble(sf);
+    ((CustomSX1262 *)_radio)->setMaxPacketMillis(calcMaxPacketMillis(sf, bw, cr, preambleLengthForSF(sf)));
   }
 
   bool isReceivingPacket() override {