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/Semaphore.c

@@ -0,0 +1,51 @@
+
+#include "cmsis_os.h"                                           // CMSIS RTOS header file
+
+/*----------------------------------------------------------------------------
+ *      Semaphore creation & usage
+ *---------------------------------------------------------------------------*/
+ 
+void Thread_Semaphore (void const *argument);                   // thread function
+osThreadId tid_Thread_Semaphore;                                // thread id
+osThreadDef (Thread_Semaphore, osPriorityNormal, 1, 0);         // thread object
+
+osSemaphoreId sid_Thread_Semaphore;                             // semaphore id
+osSemaphoreDef (SampleSemaphore);                               // semaphore object
+
+
+int Init_Semaphore (void) {
+
+  sid_Thread_Semaphore = osSemaphoreCreate (osSemaphore(SampleSemaphore), 1);
+  if (!sid_Thread_Semaphore) {
+    ; // Semaphore object not created, handle failure
+  }
+  
+  tid_Thread_Semaphore = osThreadCreate (osThread(Thread_Semaphore), NULL);
+  if (!tid_Thread_Semaphore) return(-1);
+  
+  return(0);
+}
+
+void Thread_Semaphore (void const *argument) {
+  int32_t val;
+
+  while (1) {
+    ; // Insert thread code here...
+
+    val = osSemaphoreWait (sid_Thread_Semaphore, 10);           // wait 10 mSec
+    switch (val) {
+      case osOK:
+        ; // Use protected code here...
+        osSemaphoreRelease (sid_Thread_Semaphore);              // Return a token back to a semaphore
+        break;
+      case osErrorResource:
+        break;
+      case osErrorParameter:
+        break;
+      default:
+        break;
+    }
+
+    osThreadYield ();                                           // suspend thread
+  }
+}