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/Device/ARM/ARMCM23/Debug/ARMv8MBL.dbgconf

@@ -0,0 +1,13 @@
+// <<< Use Configuration Wizard in Context Menu >>>
+
+// <e> Fixed Debug Authentication
+// <i> Use a fixed value for Debug Authentication. Only secure debug authentication configurable.
+DAuthFixed  = 0x1;
+
+//   <q.2> Secure Invasive Debug
+//   <q.3> Secure Non-Invasive Debug
+DAuthConfig = 0xF;
+
+// </e>
+
+// <<< end of configuration section >>>