OLED Pin	ESP32 GPIO	Notes
GND	GND
VCC	3.3V	3.3V only
SCK (D0)	GPIO 15	Software SPI clock
SDA (D1)	GPIO 13	Software SPI data
RES (RESET)	GPIO 4	Hardware reset
DC (A0)	GPIO 16	Data/Command select
CS	GPIO 17	Chip select (active LOW)

Note

Software SPI is used to avoid bus conflicts with the radio’s hardware VSPI.

Screen Layouts

BOOT Screen

CODE

+----------------------------------+
| AEGIS-BEACON v6.0          [87%]|  <-- Inverted header with battery
| Emergency Radio System           |
|                                  |
| [Features enabled]               |
|                                  |
| Initializing...                  |
| [========              ] 45%     |  <-- Progress bar
+----------------------------------+

BEACON Screen

CODE

+----------------------------------+
| TX BEACON #12             [87%]|  <-- Inverted header
|                                  |
|       433.500 MHz                |  <-- Large frequency
|                                  |
| CH:3 PWR:17 WPM:13              |  <-- Info line
| [==============        ] 67%     |  <-- TX progress
| > SOS DE MARIO ROSSI PSN...     |  <-- Scrolling payload
|                                  |
| GPS:FIX BAT:87% SLP:8s  [ADJ]  |  <-- Status bar
+----------------------------------+

SEARCH Screen

CODE

+----------------------------------+
| RX SEARCH #5               [87%]|  <-- Inverted header
|                                  |
|       433.500 MHz                |  <-- Large frequency
|     -87 dBm                     |  <-- RSSI value
| [#########...........]  MEDIUM  |  <-- RSSI bar
|                                  |
| HIT: 434.500 MHz -87dBm         |  <-- Last detection
| SCAN:12 BAT:87%          [ADJ]  |  <-- Status bar
+----------------------------------+

LISTEN Screen

CODE

+----------------------------------+
| RX LISTEN                  12 CHR|  <-- Inverted header + count
|                                  |
| 433.500 MHz               [87%]  |
| [#########...........]           |  <-- RSSI strip-chart
| RSSI -72dBm  THR -90dBm         |
| SOS DE LEO-GALLI 46.49          |  <-- Decoded text (2 lines)
| 83N 11.3558E                    |
+----------------------------------+

EMERGENCY Screen

CODE

+----------------------------------+
|                                  |
|          E M E R G E N C Y      |  <-- Alternating inverse
|                                  |
|             SOS                  |  <-- Giant SOS
|    EMERGENCY BEACON TX           |
|                                  |
|    433.500 MHz @ +22 dBm        |
|    N4553 E01230                  |
|                                  |
+----------------------------------+

GPS WAIT Screen

CODE

+----------------------------------+
| ACQUIRING GPS FIX          [87%]|  <-- Inverted header
|                                  |
|            6                     |  <-- Satellite count
|                                  |
| [============          ] 60%     |  <-- Progress bar
|                                  |
| Fix: 45.53124 12.30456           |
| MODE: skip wait                  |
+----------------------------------+

CONFIG Screen

CODE

+----------------------------------+
| CONFIGURATION MODE               |  <-- Inverted header
|                                  |
| SSID: AegisBeacon                |
| URL: 192.168.4.1                 |
|                                  |
| 1. Connect to WiFi               |
| 2. Open browser                  |
| 3. Configure settings            |
+----------------------------------+

Battery Icon

Located in top-right corner of header bar.

Fill Level	Battery %	Icon
4 segments	76-100%	`[====]`
3 segments	51-75%	`[=== ]`
2 segments	26-50%	`[== ]`
1 segment	11-25%	`[= ]`
Blinking !	0-10%	`[! ]` blinks every 500ms
Letter C	Charging	`[ C ]`

Warning

Battery icon blinks when charge drops below 10%. Replace or recharge immediately.

Display Features

Large Frequency Display

Uses logisoso24 font for maximum readability outdoors. Clear at arm’s length distance.

GPS Fix Indicator

Solid square: Fix acquired
Outline square: Searching for fix
No indicator: GPS disabled

Adj Overlay

Bottom 12px inverted bar shows live VOL or WPM while adjusting. Appears for 2.5 seconds after button press.

TX Payload Scroll

Message scrolls through bottom bar during transmission. Shows full SOS DE MARIO ROSSI PSN N4553 E01230.

Power Save

OLED turns off before deep sleep:

CODE

u8g2.setPowerSave(1); // Turn off
u8g2.setPowerSave(0); // Turn on

Invert Mode

Configurable for bright sunlight readability. Toggle via CONFIG portal or NVS setting.

U8g2 Configuration

CODE

#include <U8g2lib.h>

// Software SPI constructor
U8g2_SSD1309_128X64_NONAME_1_4W_SW_SPI u8g2(
  U8G2_R0,     // Rotation
  15,          // SCK
  13,          // SDA/MOSI
  17,          // CS
  16,          // DC
  4            // RESET
);

void initOLED() {
  u8g2.begin();
  u8g2.setFlipMode(0);
  u8g2.setFontMode(1);
}

Tip

U8g2 full-frame buffer eliminates flicker. Each screen update draws to buffer then sends in one SPI transaction.