fix: Internal PXX exclusive S.PORT (#3822)

radio/src/pulses/pxx.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) EdgeTX
+ *
+ * Based on code named
+ *   opentx - https://github.com/opentx/opentx
+ *   th9x - http://code.google.com/p/th9x
+ *   er9x - http://code.google.com/p/er9x
+ *   gruvin9x - http://code.google.com/p/gruvin9x
+ *
+ * License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "pxx.h"
+#include "hal/module_port.h"
+
+bool pxxClearSPort()
+{
+  auto sport_module = modulePortGetModuleForPort(ETX_MOD_PORT_SPORT);
+  if (sport_module >= 0) {
+    // verify S.PORT is not used for TX (otherwise fail early)
+    auto mod_st = modulePortGetState(sport_module);
+    if (mod_st && mod_st->tx.port &&
+        mod_st->tx.port->port == ETX_MOD_PORT_SPORT) {
+      return false;
+    }
+  } else {
+    // S.PORT soft-serial cannot be used for sending
+    sport_module = modulePortGetModuleForPort(ETX_MOD_PORT_SPORT_INV);
+  }
+
+  if (sport_module >= 0) {
+    auto mod_st = modulePortGetState(sport_module);
+    if (mod_st) modulePortDeInitRxPort(mod_st);
+  }
+
+  return true;
+}