Switched the SbusRx Begin method to a bool to indicate whether a pack…

…et was received within the timeout.
dannysilence · Mar 11, 2021 · 95a1176 · 95a1176
1 parent 004139f
commit 95a1176
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Showing 6 changed files with 22 additions and 7 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## v2.1.0
+- Added a timeout to the SbusRx.Begin() method to indicate whether a packet was received
+
 ## v2.0.0
 - Updated to namespace *bfs*
 - Updated sensors::Sbus to SbusRx and actuators::Sbus to SbusTx

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -5,7 +5,7 @@ if (DEFINED MCU)
 endif()
 # Project information
 project(Sbus
-	VERSION 1.1.6
+	VERSION 2.0.1
 	DESCRIPTION "SBUS encoder and decoder"
 	LANGUAGES C CXX
 )

diff --git a/README.md b/README.md
@@ -63,7 +63,7 @@ This library is within the namespace *bfs*
 bfs::SbusRx sbus(&Serial1);
 ```
 
-**void Begin()** Initializes SBUS communication.
+**bool Begin()** Initializes SBUS communication, returns true if an SBUS packet is received within the timeout (5 seconds) otherwise returns false.
 
 ```C++
 sbus.Begin();

diff --git a/examples/sbus_example.cc b/examples/sbus_example.cc
@@ -26,16 +26,19 @@
 #include "sbus/sbus.h"
 
 /* SBUS object, reading SBUS */
-bfs::SbusRx sbus_rx(&Serial1);
+bfs::SbusRx sbus_rx(&Serial2);
 /* SBUS object, writing SBUS */
-bfs::SbusTx sbus_tx(&Serial1);
+bfs::SbusTx sbus_tx(&Serial2);
 
 int main() {
   /* Serial to display data */
   Serial.begin(115200);
   while(!Serial) {}
   /* Begin communicating on SBUS serial */
-  sbus_rx.Begin();
+  if (!sbus_rx.Begin()) {
+    Serial.println("Unable to establish communication with SBUS receiver");
+    while (1) {}
+  }
   sbus_tx.Begin();
   while(1) {
     /* Check if SBUS packet received */

diff --git a/include/sbus/sbus.h b/include/sbus/sbus.h
@@ -34,7 +34,7 @@ namespace bfs {
 class SbusRx {
  public:
   explicit SbusRx(HardwareSerial *bus) : bus_(bus) {}
-  void Begin();
+  bool Begin();
   bool Read();
   inline std::array<uint16_t, 16> rx_channels() const {return ch_;}
   inline bool failsafe() const {return failsafe_;}
@@ -46,6 +46,7 @@ class SbusRx {
   /* Communication */
   HardwareSerial *bus_;
   static constexpr uint32_t BAUD_ = 100000;
+  static constexpr unsigned int TIMEOUT_MS_ = 5000;
   /* Parsing */
   static constexpr uint8_t HEADER_ = 0x0F;
   static constexpr uint8_t FOOTER_ = 0x00;

diff --git a/src/sbus/sbus.cc b/src/sbus/sbus.cc
@@ -27,7 +27,7 @@
 
 namespace bfs {
 
-void SbusRx::Begin() {
+bool SbusRx::Begin() {
   state_ = 0;
   prev_byte_ = FOOTER_;
   #if defined(__MK20DX128__) || defined(__MK20DX256__)
@@ -37,6 +37,14 @@ void SbusRx::Begin() {
   #endif
   /* flush the bus */
   bus_->flush();
+  /* check communication */
+  elapsedMillis timer_ms = 0;
+  while (timer_ms < TIMEOUT_MS_) {
+    if (Read()) {
+      return true;
+    }
+  }
+  return false;
 }
 bool SbusRx::Read() {
   bool status = false;