Reorganize code in prep for hardware decoupling and port to C++

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/avclan/mediacontrol.h

@@ -0,0 +1,46 @@
+/*
+                        AVCLAN-Mockingboard
+    Copyright (C) 2015 Allen Hill <allenofthehills@gmail.com>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    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.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+// Media-control actuator: emulates play/pause and skip button presses on the
+// audio source by toggling MIC_CONTROL (PB1/WO1) with TCA0 in FRQ mode.
+
+#ifndef MEDIACONTROL_H
+#define MEDIACONTROL_H
+
+#include <stdbool.h>
+
+// One-time hardware bring-up for the mic/button-press driver (TCA0 + PB1).
+void mediacontrol_init();
+
+// Emulate a single play/pause button press on the source device.
+void AVCLAN_micPlayPause();
+// Emulate skip-forward/backward button presses
+void AVCLAN_micSkipForward();
+void AVCLAN_micSkipBackward();
+
+// Keep the press waveform roughly in sync while a bus transaction has masked
+// interrupts. MUST be called with interrupts disabled (e.g. from within the
+// frame layer's AVCLAN_stopEvent ATOMIC_BLOCK).
+void mediacontrol_syncDuringMask();
+
+#ifndef NDEBUG
+bool AVCLAN_micToggle();
+bool AVCLAN_isMediaFunctioning();
+#endif
+
+#endif // MEDIACONTROL_H