docs/wiring_diagram.md

Wiring Diagrams for Dual PN532 NFC System

ESP32-C3 Super Mini Pinout Reference

                    ESP32-C3 Super Mini
                    ┌─────────────────┐
                    │  [USB-C]        │
                    │                 │
            3V3  ●──┤ 3V3         GND ├──● GND
            GND  ●──┤ GND          D0 ├──● GPIO0
             D1  ●──┤ D1           D1 ├──● GPIO1
             D2  ●──┤ D2           D2 ├──● GPIO2
             D3  ●──┤ D3           D3 ├──● GPIO3
             D4  ●──┤ D4           D4 ├──● GPIO4
             D5  ●──┤ D5           D5 ├──● GPIO5
             D6  ●──┤ D6           D6 ├──● GPIO6
             D7  ●──┤ D7           D7 ├──● GPIO7
             D8  ●──┤ D8           D8 ├──● GPIO8
             D9  ●──┤ D9           D9 ├──● GPIO9
            D10  ●──┤ D10         D10 ├──● GPIO10
                    └─────────────────┘

Listener Module Wiring

ESP32-C3 to PN532 (I2C Mode)

ESP32-C3 Super Mini          PN532 Module
┌─────────────────┐         ┌─────────────┐
│                 │         │             │
│ 3V3         ────┼─────────┤ VCC         │
│ GND         ────┼─────────┤ GND         │
│ GPIO8 (SDA) ────┼─────────┤ SDA         │
│ GPIO9 (SCL) ────┼─────────┤ SCL         │
│ GPIO10      ────┼─────────┤ LED (opt)   │
│                 │         │             │
└─────────────────┘         └─────────────┘

PN532 DIP Switch Configuration (I2C Mode)

Switch 1: OFF (I2C mode)
Switch 2: OFF (I2C mode)

Emulator Module Wiring

ESP32-C3 to PN532 (I2C Mode)

ESP32-C3 Super Mini          PN532 Module
┌─────────────────┐         ┌─────────────┐
│                 │         │             │
│ 3V3         ────┼─────────┤ VCC         │
│ GND         ────┼─────────┤ GND         │
│ GPIO8 (SDA) ────┼─────────┤ SDA         │
│ GPIO9 (SCL) ────┼─────────┤ SCL         │
│                 │         │             │
└─────────────────┘         └─────────────┘

ESP32-C3 to SD Card Module (SPI Mode)

ESP32-C3 Super Mini          SD Card Module
┌─────────────────┐         ┌─────────────┐
│                 │         │             │
│ 3V3         ────┼─────────┤ VCC         │
│ GND         ────┼─────────┤ GND         │
│ GPIO10 (CS) ────┼─────────┤ CS          │
│ GPIO6 (MOSI)────┼─────────┤ MOSI        │
│ GPIO5 (MISO)────┼─────────┤ MISO        │
│ GPIO4 (SCK) ────┼─────────┤ SCK         │
│ GPIO2       ────┼─────────┤ LED (opt)   │
│                 │         │             │
└─────────────────┘         └─────────────┘

Complete Emulator Module Wiring

                    ESP32-C3 Super Mini
                    ┌─────────────────┐
                    │                 │
        PN532 VCC ──┤ 3V3             │
     SD Card VCC ──┤                 │
                    │                 │
        PN532 GND ──┤ GND             │
     SD Card GND ──┤                 │
                    │                 │
                    │             D2 ├── LED (Status)
                    │             D4 ├── SD Card SCK
                    │             D5 ├── SD Card MISO
                    │             D6 ├── SD Card MOSI
                    │             D8 ├── PN532 SDA
                    │             D9 ├── PN532 SCL
                    │            D10 ├── SD Card CS
                    │                 │
                    └─────────────────┘

Power Considerations

• Voltage: Both PN532 and SD card modules operate at 3.3V
• Current: ESP32-C3 can provide sufficient current for both modules
• Power Supply: Use quality USB cable or external 3.3V supply for stable operation

Troubleshooting

I2C Issues

• Check SDA/SCL connections
• Verify pull-up resistors (usually built into modules)
• Ensure PN532 DIP switches are set correctly

SD Card Issues

• Verify SPI connections
• Check SD card formatting (FAT32 recommended)
• Ensure proper power supply

Communication Issues

• Check ESP-NOW channel settings
• Verify both modules are powered and programmed correctly
• Monitor serial output for pairing status

LED Status Indicators

Listener Module (GPIO10)

• 3 quick blinks: System startup
• 5 quick blinks: Successfully paired with emulator
• Solid ON: NFC tag detected
• Single blink every 500ms: PN532 error

Emulator Module (GPIO2)

• 3 quick blinks: System startup
• 5 quick blinks: Successfully paired with listener
• Solid ON: Emulating NFC tag
• Single blink every 500ms: PN532 error