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/RTX/UserCodeTemplates/main.c

@@ -0,0 +1,21 @@
+/*----------------------------------------------------------------------------
+ * CMSIS-RTOS 'main' function template
+ *---------------------------------------------------------------------------*/
+
+#define osObjectsPublic                     // define objects in main module
+#include "osObjects.h"                      // RTOS object definitions
+
+
+/*
+ * main: initialize and start the system
+ */
+int main (void) {
+  osKernelInitialize ();                    // initialize CMSIS-RTOS
+
+  // initialize peripherals here
+
+  // create 'thread' functions that start executing,
+  // example: tid_name = osThreadCreate (osThread(name), NULL);
+
+  osKernelStart ();                         // start thread execution 
+}