From a651fcc05ecef6bff2db5d47533d02bf8c81ff6c Mon Sep 17 00:00:00 2001
From: "Pawel Spychalski (DzikuVx)" <pspychalski@gmail.com>
Date: Thu, 19 Apr 2018 16:24:17 +0200
Subject: [PATCH] imporved sbus input handling on TX module

---
 crossbow/config.h     |  4 ++--
 crossbow/crossbow.ino | 13 +++++++++++++
 crossbow/sbus.cpp     | 10 ++++++++--
 crossbow/sbus.h       |  1 +
 4 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/crossbow/config.h b/crossbow/config.h
index 9706f06..3e1a467 100644
--- a/crossbow/config.h
+++ b/crossbow/config.h
@@ -13,8 +13,8 @@
  * DEVICE_MODE_TX
  * DEVICE_MODE_RX
  */
-// #define DEVICE_MODE_TX
-#define DEVICE_MODE_RX
+#define DEVICE_MODE_TX
+// #define DEVICE_MODE_RX
 
 // #define FEATURE_TX_OLED
 // #define FORCE_TX_WITHOUT_INPUT
diff --git a/crossbow/crossbow.ino b/crossbow/crossbow.ino
index 0678e3b..4dd5840 100644
--- a/crossbow/crossbow.ino
+++ b/crossbow/crossbow.ino
@@ -327,6 +327,19 @@ void loop(void)
     uint32_t currentMillis = millis();
 
     /*
+     * If we are not receiving SBUS frames from radio, try to restart serial
+     */
+#ifdef DEVICE_MODE_TX
+
+    static uint32_t serialRestartMillis = 0;
+
+    if (!txInput.isReceiving() && serialRestartMillis + 100 < currentMillis) {
+        txInput.restart();
+        serialRestartMillis = currentMillis;
+    }
+#endif
+
+    /*
      * This routine handles resync of TX/RX while hoppping frequencies
      */
 #ifdef DEVICE_MODE_RX
diff --git a/crossbow/sbus.cpp b/crossbow/sbus.cpp
index 881ccbc..47642ef 100644
--- a/crossbow/sbus.cpp
+++ b/crossbow/sbus.cpp
@@ -13,7 +13,7 @@
 #define SBUS_STATE_FAILSAFE 0x08
 #define SBUS_STATE_SIGNALLOSS 0x04
 
-#define SBUS_IS_RECEIVING_THRESHOLD 250 //If there is no SBUS input for 250ms, assume connection is broken
+#define SBUS_IS_RECEIVING_THRESHOLD 125 //If there is no SBUS input for 125ms, assume connection is broken
 
 /*
 Precomputed mapping from 990-2010 to 173:1811
@@ -93,7 +93,13 @@ void SbusInput::loop(void)
 
 void SbusInput::start(void)
 {
-        _serial.begin(100000, SERIAL_8N2);
+    _serial.begin(100000, SERIAL_8N2);
+}
+
+void SbusInput::restart(void)
+{   
+    _serial.end();
+    start();
 }
 
 void SbusInput::sbusRead() {
diff --git a/crossbow/sbus.h b/crossbow/sbus.h
index 261b49e..9b92ecc 100644
--- a/crossbow/sbus.h
+++ b/crossbow/sbus.h
@@ -11,6 +11,7 @@ class SbusInput : public TxInput
   public:
   	SbusInput(HardwareSerial &serial);
     void start(void);
+    void restart(void);
     void loop(void);
     bool isReceiving(void);
   private: