Hardware Hacking: UART Serial Configuration

Configuring and interfacing with Santa's Little Helper (SLH) Access Card Maintenance Tool via UART

UART Hardware Serial Communication

Hardware Documentation

NP2103 UART-BRIDGE Specifications

Pin Configuration

  • VCC - Voltage Supply
  • TX - Data Transmit
  • RX - Data Receive
  • GND - Ground

Voltage Settings

  • 3V Operation Mode
  • 5V Operation Mode
  • Selectable via Toggle

Physical Connections

Device     UART Bridge
VCC   →   VCC
GND   →   GND
TX    →   RX    (Cross-connected)
RX    →   TX    (Cross-connected)

Critical Notes

  • Ensure TX/RX lines are crossed between device and bridge
  • Verify voltage selection matches device requirements
  • Double-check ground connection

Serial Configuration

Communication Parameters

  • Port: USB/COM
  • Baud Rate: 9600
  • Data Bits: 8
  • Parity: None
  • Stop Bits: 1
  • Flow Control: None

Implementation Steps

  1. Connect hardware following pin diagram
  2. Select appropriate voltage setting
  3. Configure serial parameters
  4. Establish connection
  5. Verify device response

Steps

Steps taken

Once I had the reconstructed document with the proper UART configuration settings, I simply had to connect each wire to the correct pin, plug in the USB and test the settings.

Security Implications

Security Considerations

  • Access control implications
  • Secure configuration storage
  • Hardware interface protection
  • Authentication mechanisms

Key Learnings

  • UART communication basics
  • Hardware interface security
  • Serial protocol fundamentals
  • Physical security aspects