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)

app/scanner.h

@@ -0,0 +1,57 @@
+/* Copyright 2023 Dual Tachyon
+ * https://github.com/DualTachyon
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *     Unless required by applicable law or agreed to in writing, software
+ *     distributed under the License is distributed on an "AS IS" BASIS,
+ *     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *     See the License for the specific language governing permissions and
+ *     limitations under the License.
+ */
+
+#ifndef APP_SCANNER_H
+#define APP_SCANNER_H
+
+#include "dcs.h"
+#include "driver/keyboard.h"
+
+typedef enum 
+{
+	SCAN_CSS_STATE_OFF,
+	SCAN_CSS_STATE_SCANNING,
+	SCAN_CSS_STATE_FOUND,
+	SCAN_CSS_STATE_FAILED
+} SCAN_CssState_t;
+
+typedef enum 
+{
+	SCAN_SAVE_NO_PROMPT, // saving process not initiated
+	SCAN_SAVE_CHAN_SEL,  // "SAVE: ", channel select prompt, actives only in channel mode
+	SCAN_SAVE_CHANNEL,   // "SAVE?" prompt, waits for confirmation to save settings to channel, or current VFO 
+} SCAN_SaveState_t;
+
+
+extern DCS_CodeType_t    gScanCssResultType;
+extern uint8_t           gScanCssResultCode;
+extern bool              gScanSingleFrequency;
+extern SCAN_SaveState_t  gScannerSaveState;
+extern uint8_t           gScanChannel;
+extern uint32_t          gScanFrequency;
+extern SCAN_CssState_t   gScanCssState;
+extern uint8_t           gScanProgressIndicator;
+extern bool              gScanUseCssResult;
+
+void SCANNER_ProcessKeys(KEY_Code_t Key, bool bKeyPressed, bool bKeyHeld);
+void SCANNER_Start(bool singleFreq);
+void SCANNER_Stop(void);
+void SCANNER_TimeSlice10ms(void);
+void SCANNER_TimeSlice500ms(void);
+bool SCANNER_IsScanning(void);
+
+#endif
+