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/DoxyGen/Driver/src/Flash_Demo.c

@@ -0,0 +1,55 @@
+#include "Driver_Flash.h"
+#include "cmsis_os2.h"                  // ARM::CMSIS:RTOS2:Keil RTX5
+   
+/* Flash driver instance */
+extern ARM_DRIVER_FLASH Driver_Flash0;
+static ARM_DRIVER_FLASH * flashDev = &Driver_Flash0;
+ 
+/* CMSIS-RTOS2 Thread Id */
+osThreadId_t Flash_Thread_Id;
+ 
+/* Flash signal event */
+void Flash_Callback(uint32_t event)
+{
+  if (event & ARM_FLASH_EVENT_READY) {
+    /* The read/program/erase operation is completed */
+    osThreadFlagsSet(Flash_Thread_Id, 1U);
+  }
+  if (event & ARM_FLASH_EVENT_ERROR) {
+    /* The read/program/erase operation is completed with errors */
+    /* Call debugger or replace with custom error handling */
+    __breakpoint(0);  
+  }
+} 
+ 
+/* CMSIS-RTOS2 Thread */ 
+void Flash_Thread (void *argument)
+{
+  /* Query drivers capabilities */
+  const ARM_FLASH_CAPABILITIES capabilities = flashDev->GetCapabilities();
+ 
+  /* Initialize Flash device */
+  if (capabilities.event_ready) {
+    flashDev->Initialize (&Flash_Callback);
+  } else {
+    flashDev->Initialize (NULL);
+  }
+  
+  /* Power-on Flash device */
+  flashDev->PowerControl (ARM_POWER_FULL);
+  
+  /* Read data taking data_width into account */
+  uint8_t buf[256U];
+  flashDev->ReadData (0x1000U, buf, sizeof(buf)>>capabilities.data_width);
+  
+  /* Wait operation to be completed */
+  if (capabilities.event_ready) {
+    osThreadFlagsWait (1U, osFlagsWaitAny, 100U);
+  } else {
+    osDelay(100U);
+  }
+  
+  /* Switch off gracefully */
+  flashDev->PowerControl (ARM_POWER_OFF);
+  flashDev->Uninitialize ();
+}