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)

ui/scanner.c

@@ -0,0 +1,83 @@
+/* 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.
+ */
+
+#include <stdbool.h>
+#include <string.h>
+#include "app/scanner.h"
+#include "dcs.h"
+#include "driver/st7565.h"
+#include "external/printf/printf.h"
+#include "misc.h"
+#include "ui/helper.h"
+#include "ui/scanner.h"
+
+void UI_DisplayScanner(void)
+{
+	char  String[16] = {0};
+	char *pPrintStr = String;
+	bool bCentered;
+	uint8_t Start;
+
+	UI_DisplayClear();
+
+	if (gScanSingleFrequency || (gScanCssState != SCAN_CSS_STATE_OFF && gScanCssState != SCAN_CSS_STATE_FAILED)) {
+		sprintf(String, "FREQ:%u.%05u", gScanFrequency / 100000, gScanFrequency % 100000);
+		pPrintStr = String;
+	} else {
+		pPrintStr = "FREQ:**.*****";
+	}
+
+	UI_PrintString(pPrintStr, 2, 0, 1, 8);
+
+	if (gScanCssState < SCAN_CSS_STATE_FOUND || !gScanUseCssResult) {
+		pPrintStr = "CTC:******";
+	} else if (gScanCssResultType == CODE_TYPE_CONTINUOUS_TONE) {
+		sprintf(String, "CTC:%u.%uHz", CTCSS_Options[gScanCssResultCode] / 10, CTCSS_Options[gScanCssResultCode] % 10);
+		pPrintStr = String;
+	} else {
+		sprintf(String, "DCS:D%03oN", DCS_Options[gScanCssResultCode]);
+		pPrintStr = String;
+	}
+
+	UI_PrintString(pPrintStr, 2, 0, 3, 8);
+	memset(String, 0, sizeof(String));
+	if (gScannerSaveState == SCAN_SAVE_CHANNEL) {
+		pPrintStr = "SAVE?";
+		Start     = 0;
+		bCentered = 1;
+	} else {
+		Start     = 2;
+		bCentered = 0;
+
+		if (gScannerSaveState == SCAN_SAVE_CHAN_SEL) {
+			strcpy(String, "SAVE:");
+			UI_GenerateChannelStringEx(String + 5, gShowChPrefix, gScanChannel);
+			pPrintStr = String;
+		} else if (gScanCssState < SCAN_CSS_STATE_FOUND) {
+			strcpy(String, "SCAN");
+			memset(String + 4, '.', (gScanProgressIndicator & 7) + 1);
+			pPrintStr = String;
+		} else if (gScanCssState == SCAN_CSS_STATE_FOUND) {
+			pPrintStr = "SCAN CMP.";
+		} else {
+			pPrintStr = "SCAN FAIL.";
+		}
+	}
+
+	UI_PrintString(pPrintStr, Start, bCentered ? 127 : 0, 5, 8);
+
+	ST7565_BlitFullScreen();
+}