For various micro-controller projects, we use UART ↔ USB converters from FTDIchip: http://www.ftdichip.com

We typically use only one of two types of converter chip:

• FT232R
  • provides ONE UART ↔ USB converter per chip
  • standalone chip, 10x6mm, PCB size 15x14mm
  • data transmission up to 3MBaud (typically used up to 2MBaud)
  • uses “only” USB2.0 full speed (12MHz), large individual data packages on USB
  • some issues have been observed with high packet latencies (in the order of 16ms)

• FT232H / FT2232H
  • provides ONE or TWO UART ↔ USB converters per chip
  • various other components on PCB (such as voltage regulator, crystal)
  • data transmission up to 12MBaud
  • uses USB2.0 high speed (480MHz), micro packages on USB bus

If you need to locate those devices on your USB bus (or need to remove drivers), here are vendor and device IDs:

These converters show up as one (<x>) or two (<x>+<y>) virtual serial port(s) on Windows / Linux / MaxOS:

• Windows: COM<x> and COM<y>
• Linux: /dev/ttyUSB<x> and /dev/ttyUSB<y>
• Mac-OSX: /dev/cu.usbserial-<x> and /dev/cu.usbserial-<y>

Make sure you download the latest drivers for your OS from here: http://www.ftdichip.com/Drivers/VCP.htm

Here is an application note from FTDI explaining how to alias baud rates (i.e. how to tune a baud rate to non-standard values): ftdi-an_120_aliasing_vcp_baud_rates.pdf

Check the provided software tools here http://www.ftdichip.com/Support/Utilities.htm; e.g. a tool to set custom baud rates!

Here is a short demo program for MacOSX (which you need to tune to your requirements): ftdi-macosx-example.zip