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/fmradio.c

@@ -0,0 +1,102 @@
+/* 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.
+ */
+
+#ifdef ENABLE_FMRADIO
+
+#include <string.h>
+
+#include "app/fm.h"
+#include "driver/bk1080.h"
+#include "driver/st7565.h"
+#include "external/printf/printf.h"
+#include "misc.h"
+#include "settings.h"
+#include "ui/fmradio.h"
+#include "ui/helper.h"
+#include "ui/inputbox.h"
+#include "ui/ui.h"
+
+void UI_DisplayFM(void)
+{
+	char String[16] = {0};
+	char *pPrintStr = String;
+	UI_DisplayClear();
+
+	UI_PrintString("FM", 2, 0, 0, 8);
+
+	sprintf(String, "%d%s-%dM", 
+		BK1080_GetFreqLoLimit(gEeprom.FM_Band)/10,
+		gEeprom.FM_Band == 0 ? ".5" : "",
+		BK1080_GetFreqHiLimit(gEeprom.FM_Band)/10
+		);
+	
+	UI_PrintStringSmallNormal(String, 1, 0, 6);
+
+	//uint8_t spacings[] = {20,10,5};
+	//sprintf(String, "%d0k", spacings[gEeprom.FM_Space % 3]);
+	//UI_PrintStringSmallNormal(String, 127 - 4*7, 0, 6);
+
+	if (gAskToSave) {
+		pPrintStr = "SAVE?";
+	} else if (gAskToDelete) {
+		pPrintStr = "DEL?";
+	} else if (gFM_ScanState == FM_SCAN_OFF) {
+		if (gEeprom.FM_IsMrMode) {
+			sprintf(String, "MR(CH%02u)", gEeprom.FM_SelectedChannel + 1);
+			pPrintStr = String;
+		} else {
+			pPrintStr = "VFO";
+			for (unsigned int i = 0; i < 20; i++) {
+				if (gEeprom.FM_FrequencyPlaying == gFM_Channels[i]) {
+					sprintf(String, "VFO(CH%02u)", i + 1);
+					pPrintStr = String;
+					break;
+				}
+			}
+		}
+	} else if (gFM_AutoScan) {
+		sprintf(String, "A-SCAN(%u)", gFM_ChannelPosition + 1);
+		pPrintStr = String;
+	} else {
+		pPrintStr = "M-SCAN";
+	}
+
+	UI_PrintString(pPrintStr, 0, 127, 3, 10); // memory, vfo, scan
+
+	memset(String, 0, sizeof(String));
+	if (gAskToSave || (gEeprom.FM_IsMrMode && gInputBoxIndex > 0)) {
+		UI_GenerateChannelString(String, gFM_ChannelPosition);
+	} else if (gAskToDelete) {
+		sprintf(String, "CH-%02u", gEeprom.FM_SelectedChannel + 1);
+	} else {
+		if (gInputBoxIndex == 0) {
+			sprintf(String, "%3d.%d", gEeprom.FM_FrequencyPlaying / 10, gEeprom.FM_FrequencyPlaying % 10);
+		} else {
+			const char * ascii = INPUTBOX_GetAscii();
+			sprintf(String, "%.3s.%.1s",ascii, ascii + 3);
+		}
+
+		UI_DisplayFrequency(String, 36, 1, gInputBoxIndex == 0);  // frequency
+		ST7565_BlitFullScreen();
+		return;
+	}
+
+	UI_PrintString(String, 0, 127, 1, 10);
+
+	ST7565_BlitFullScreen();
+}
+
+#endif