UA1ZBE Custom Firmware v1.0

Features:
- VFO mode with direct frequency input
- POCSAG decoder (512/1200 baud) with BCH(31,21) correction
- Full-screen Spectrum analyzer
- FM Radio receiver
- RSSI signal indicator overlay
- Custom boot splash (UA1ZBE / POCSAG pager / build date)

Architecture:
- app/mode.c — mode dispatcher (VFO/POCSAG/Spectrum/FM)
- app/boot_splash.c — 2-second boot splash
- app/pocsag/ — POCSAG decoder + BCH correction
- app/display_rssi.c — RSSI indicator
- main.c — entry point with custom init
- syscalls.c — bare-metal _sbrk stub

Build: arm-none-eabi-gcc -Os -flto -Wall -Werror -Wextra
Size: 57.9KB Flash / 3.6KB RAM

Controls:
- 0-9: Direct frequency input (VFO)
- SK2: POCSAG mode
- SK1: Spectrum analyzer
- 0: FM Radio
- EXIT: Return to VFO
- F/*: Toggle 512/1200 baud (in POCSAG)

external/CMSIS_5/CMSIS/RTOS/Template/CPP/Mutex.h

@@ -0,0 +1,43 @@
+/* Copyright (c) 2012 mbed.org */
+#ifndef MUTEX_H
+#define MUTEX_H 
+
+#include <stdint.h>
+#include "cmsis_os.h"
+
+namespace rtos {
+
+/*! The Mutex class is used to synchronise the execution of threads.
+ This is for example used to protect access to a shared resource.
+*/
+class Mutex {
+public:
+    /*! Create and Initialize a Mutex object */
+    Mutex();
+    
+    /*! Wait until a Mutex becomes available.
+      \param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever)
+      \return  status code that indicates the execution status of the function.
+     */ 
+    osStatus lock(uint32_t millisec=osWaitForever);
+    
+    /*! Try to lock the mutex, and return immediately
+      \return  true if the mutex was acquired, false otherwise.
+     */
+    bool trylock();
+    
+    /*! Unlock the mutex that has previously been locked by the same thread
+      \return  status code that indicates the execution status of the function. 
+     */
+    osStatus unlock();
+
+private:
+    osMutexId _osMutexId;
+    osMutexDef_t _osMutexDef;
+#ifdef CMSIS_OS_RTX
+    int32_t _mutex_data[3];
+#endif
+};
+
+}
+#endif