OPTOUSB

Features

• USB to TTL level Serial (FTDI) Interface
  • Genuine FTDI FT230XS part
  • Standard FTDI drivers
• Buffered lines on the TTL level side
  • Schmidt Trigger
    • Voltage level hysteresis
    • Improved slew rate
• OptoIsolated Connections
  • Transmit, Receive, RTS, CTS
  • Configured for High Speed Serial
• The Host USB connection is independent of the state of the FTDI side of the interface
  • Host side can communicate with the USB host whether or not the target is even powered up
  • Target power on/off doesn't cause a USB disconnect - handy for debug
• Fast operation
• 3.3V or 5V FTDI voltage (order option)
• Transmit/Receive LED Connectors
  • On-board LED resistors
  • 49x49mm card
  • (4) #4 Mounting Holes

Block Diagram

Separate Power Domains

• The OPTOUSB card has two distinct power domains.
  • One of the domains is the USB side where the power comes from the USB connector/cable.
  • The other power domain is on the TTL side where the power comes from the FTDI connector.
• This is unlike "normal" FTDI interfaces where the USB connection can power the FTDI side.
  • This is the purpose of the optical isolation - to isolate the ground of the USB side from the target (FTDI) side.

Connectors

J1 - Mini USB Connector

• Standard USB Mini connector

J2 - Transmit/Receive LED connections

1. PUP0 - LED Pullup to USB Power
2. TXLED - Transmit LED
3. PUP1 - LED Pullup to USB Power

RXLED - Receive LED J3 - FTDI Connector Signals are references to external system GND RTS (In to card) VCC (3.3V or 5V) - Power must be supplied to this pin Receive (Out from card) Transmit (In to card) CTS (Out from card) Drivers FTDI Drivers Layout OPTOUSB-CAD-X1.PNG

Transfer Rate Characterization LTSpice Simulation results 8.6uS per bit = 115,200 baud OPTO-USB LTSpice Simulation.png

Card Test UUT 5V Power Supply Loopback/FTDI Cable Pin 1 = Ground (5V Supply) Pin 3 = Vcc (5V Supply) Pin 2 - Pin 6 RTS/CTS Loopback Pin 4 - Pin 5 Tx/Rx Loopback Run puTTY Run Device Manager to determine COM port Set baud rate to TBD (115,200?) Loopback test Rework - Rev X1 PWBs OPTOUSB_Rev_X1_Rework

Assembly Sheet

• OPTOUSB Assembly Sheet