From 3ca1e62b1f4d07472f92b6cdb2d5403f26ab5a7b Mon Sep 17 00:00:00 2001
From: GUVWAF <78759985+GUVWAF@users.noreply.github.com>
Date: Mon, 6 Mar 2023 22:53:59 +0100
Subject: [PATCH] SX126x/8x: Add HEADER_VALID IRQ flag for actively receiving
 check (#2333)

* Add HEADER_VALID IRQ flag for SX126x/8x to detect actively receiving
Needs new RadioLib commit

* Update comments

* Use latest RadioLib release

---------

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>
---
 platformio.ini               |  3 +--
 src/mesh/SX126xInterface.cpp | 20 ++++++++------------
 src/mesh/SX128xInterface.cpp | 10 ++++++----
 3 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/platformio.ini b/platformio.ini
index af18a6f8b..fa119eccc 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -66,8 +66,7 @@ lib_deps =
   https://github.com/meshtastic/ArduinoThread.git#72921ac222eed6f526ba1682023cee290d9aa1b3
   nanopb/Nanopb@^0.4.6
   erriez/ErriezCRC32@^1.0.1
-;  jgromes/RadioLib@^5.5.1
-  https://github.com/jgromes/RadioLib.git#1afa947030c5637f71f6563bc22aa75032e53a57
+  jgromes/RadioLib@^5.7.0
 
 ; Used for the code analysis in PIO Home / Inspect
 check_tool = cppcheck
diff --git a/src/mesh/SX126xInterface.cpp b/src/mesh/SX126xInterface.cpp
index 1036042eb..54bc70a73 100644
--- a/src/mesh/SX126xInterface.cpp
+++ b/src/mesh/SX126xInterface.cpp
@@ -212,9 +212,10 @@ template <typename T> void SX126xInterface<T>::startReceive()
 
     setStandby();
 
-    // int err = lora.startReceive();
-    int err = lora.startReceiveDutyCycleAuto(); // We use a 32 bit preamble so this should save some power by letting radio sit in
-                                                // standby mostly.
+    // We use a 16 bit preamble so this should save some power by letting radio sit in standby mostly.
+    // Furthermore, we need the HEADER_VALID IRQ flag to detect whether we are actively receiving
+    int err =
+        lora.startReceiveDutyCycleAuto(preambleLength, 8, RADIOLIB_SX126X_IRQ_RX_DEFAULT | RADIOLIB_SX126X_IRQ_HEADER_VALID);
     assert(err == RADIOLIB_ERR_NONE);
 
     isReceiving = true;
@@ -224,7 +225,7 @@ template <typename T> void SX126xInterface<T>::startReceive()
 #endif
 }
 
-/** Could we send right now (i.e. either not actively receving or transmitting)? */
+/** Is the channel currently active? */
 template <typename T> bool SX126xInterface<T>::isChannelActive()
 {
     // check if we can detect a LoRa preamble on the current channel
@@ -245,17 +246,12 @@ template <typename T> bool SX126xInterface<T>::isActivelyReceiving()
 {
     // The IRQ status will be cleared when we start our read operation.  Check if we've started a header, but haven't yet
     // received and handled the interrupt for reading the packet/handling errors.
-    // FIXME: it would be better to check for preamble, but we currently have our ISR not set to fire for packets that
-    // never even get a valid header, so we don't want preamble to get set and stay set due to noise on the network.
 
     uint16_t irq = lora.getIrqStatus();
-    bool hasPreamble = (irq & RADIOLIB_SX126X_IRQ_HEADER_VALID);
+    bool headerValid = (irq & RADIOLIB_SX126X_IRQ_HEADER_VALID);
 
-    // this is not correct - often always true - need to add an extra conditional
-    // size_t bytesPending = lora.getPacketLength();
-
-    // if (hasPreamble) LOG_DEBUG("rx hasPreamble\n");
-    return hasPreamble;
+    // if (headerValid) LOG_DEBUG("rx headerValid\n");
+    return headerValid;
 }
 
 template <typename T> bool SX126xInterface<T>::sleep()
diff --git a/src/mesh/SX128xInterface.cpp b/src/mesh/SX128xInterface.cpp
index 19001a0de..308e4a52a 100644
--- a/src/mesh/SX128xInterface.cpp
+++ b/src/mesh/SX128xInterface.cpp
@@ -203,7 +203,9 @@ template <typename T> void SX128xInterface<T>::startReceive()
     digitalWrite(SX128X_TXEN, LOW);
 #endif
 
-    int err = lora.startReceive();
+    // We use the HEADER_VALID IRQ flag to detect whether we are actively receiving
+    int err =
+        lora.startReceive(RADIOLIB_SX128X_RX_TIMEOUT_INF, RADIOLIB_SX128X_IRQ_RX_DEFAULT | RADIOLIB_SX128X_IRQ_HEADER_VALID);
 
     assert(err == RADIOLIB_ERR_NONE);
 
@@ -214,7 +216,7 @@ template <typename T> void SX128xInterface<T>::startReceive()
 #endif
 }
 
-/** Could we send right now (i.e. either not actively receving or transmitting)? */
+/** Is the channel currently active? */
 template <typename T> bool SX128xInterface<T>::isChannelActive()
 {
     // check if we can detect a LoRa preamble on the current channel
@@ -234,8 +236,8 @@ template <typename T> bool SX128xInterface<T>::isChannelActive()
 template <typename T> bool SX128xInterface<T>::isActivelyReceiving()
 {
     uint16_t irq = lora.getIrqStatus();
-    bool hasPreamble = (irq & RADIOLIB_SX128X_IRQ_HEADER_VALID);
-    return hasPreamble;
+    bool hasHeader = (irq & RADIOLIB_SX128X_IRQ_HEADER_VALID);
+    return hasHeader;
 }
 
 template <typename T> bool SX128xInterface<T>::sleep()