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/welcome.c

@@ -0,0 +1,77 @@
+/* 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 <string.h>
+
+#include "driver/eeprom.h"
+#include "driver/st7565.h"
+#include "external/printf/printf.h"
+#include "helper/battery.h"
+#include "settings.h"
+#include "misc.h"
+#include "ui/helper.h"
+#include "ui/welcome.h"
+#include "ui/status.h"
+#include "version.h"
+
+void UI_DisplayReleaseKeys(void)
+{
+	memset(gStatusLine,  0, sizeof(gStatusLine));
+	UI_DisplayClear();
+
+	UI_PrintString("RELEASE", 0, 127, 1, 10);
+	UI_PrintString("ALL KEYS", 0, 127, 3, 10);
+
+	ST7565_BlitStatusLine();  // blank status line
+	ST7565_BlitFullScreen();
+}
+
+void UI_DisplayWelcome(void)
+{
+	char WelcomeString0[16];
+	char WelcomeString1[16];
+
+	memset(gStatusLine,  0, sizeof(gStatusLine));
+	UI_DisplayClear();
+
+	if (gEeprom.POWER_ON_DISPLAY_MODE == POWER_ON_DISPLAY_MODE_NONE || gEeprom.POWER_ON_DISPLAY_MODE == POWER_ON_DISPLAY_MODE_FULL_SCREEN) {
+		ST7565_FillScreen(0xFF);
+	} else {
+		memset(WelcomeString0, 0, sizeof(WelcomeString0));
+		memset(WelcomeString1, 0, sizeof(WelcomeString1));
+
+		if (gEeprom.POWER_ON_DISPLAY_MODE == POWER_ON_DISPLAY_MODE_VOLTAGE)
+		{
+			strcpy(WelcomeString0, "VOLTAGE");
+			sprintf(WelcomeString1, "%u.%02uV %u%%",
+				gBatteryVoltageAverage / 100,
+				gBatteryVoltageAverage % 100,
+				BATTERY_VoltsToPercent(gBatteryVoltageAverage));
+		}
+		else
+		{
+			EEPROM_ReadBuffer(0x0EB0, WelcomeString0, 16);
+			EEPROM_ReadBuffer(0x0EC0, WelcomeString1, 16);
+		}
+
+		UI_PrintString(WelcomeString0, 0, 127, 0, 10);
+		UI_PrintString(WelcomeString1, 0, 127, 2, 10);
+		UI_PrintStringSmallNormal(Version, 0, 128, 6);
+
+		ST7565_BlitStatusLine();  // blank status line
+		ST7565_BlitFullScreen();
+	}
+}