feat: add USB CDC bridge transport support

examples/simple_repeater/MyMesh.h

@@ -14,6 +14,10 @@
 #endif
 
 #ifdef WITH_RS232_BRIDGE
+#ifdef WITH_USB_SERIAL_BRIDGE
+#include <Adafruit_TinyUSB.h>
+extern Adafruit_USBD_CDC bridgeSerial;
+#endif
 #include "helpers/bridges/RS232Bridge.h"
 #define WITH_BRIDGE
 #endif

examples/simple_repeater/main.cpp

@@ -3,6 +3,10 @@
 
 #include "MyMesh.h"
 
+#ifdef WITH_USB_SERIAL_BRIDGE
+Adafruit_USBD_CDC bridgeSerial;
+#endif
+
 #ifdef DISPLAY_CLASS
   #include "UITask.h"
   static UITask ui_task(display);
@@ -36,6 +40,10 @@ static unsigned long userBtnDownAt = 0;
 #endif
 
 void setup() {
+#ifdef WITH_USB_SERIAL_BRIDGE
+  // Register the second CDC interface before Serial mounts the USB device.
+  bridgeSerial.begin(115200);
+#endif
   Serial.begin(115200);
   delay(1000);
 

src/helpers/bridges/RS232Bridge.cpp

@@ -2,6 +2,10 @@
 
 #include <HardwareSerial.h>
 
+#ifdef WITH_USB_SERIAL_BRIDGE
+#include <Adafruit_TinyUSB.h>
+#endif
+
 #ifdef WITH_RS232_BRIDGE
 
 RS232Bridge::RS232Bridge(NodePrefs *prefs, Stream &serial, mesh::PacketManager *mgr, mesh::RTCClock *rtc)
@@ -9,6 +13,9 @@ RS232Bridge::RS232Bridge(NodePrefs *prefs, Stream &serial, mesh::PacketManager *
 
 void RS232Bridge::begin() {
   BRIDGE_DEBUG_PRINTLN("Initializing at %d baud...\n", _prefs->bridge_baud);
+#ifdef WITH_USB_SERIAL_BRIDGE
+  static_cast<Adafruit_USBD_CDC*>(_serial)->begin(_prefs->bridge_baud);
+#else
 #if !defined(WITH_RS232_BRIDGE_RX) || !defined(WITH_RS232_BRIDGE_TX)
 #error "WITH_RS232_BRIDGE_RX and WITH_RS232_BRIDGE_TX must be defined"
 #endif
@@ -28,6 +35,7 @@ void RS232Bridge::begin() {
 #error RS232Bridge was not tested on the current platform
 #endif
   ((HardwareSerial *)_serial)->begin(_prefs->bridge_baud);
+#endif
 
   // Update bridge state
   _initialized = true;
@@ -35,7 +43,11 @@ void RS232Bridge::begin() {
 
 void RS232Bridge::end() {
   BRIDGE_DEBUG_PRINTLN("Stopping...\n");
+#ifdef WITH_USB_SERIAL_BRIDGE
+  static_cast<Adafruit_USBD_CDC*>(_serial)->end();
+#else
   ((HardwareSerial *)_serial)->end();
+#endif
 
   // Update bridge state
   _initialized = false;