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I have a data logger with a USB output (FTDI FT232RL) and I'm trying to get the information remotely using a XBee modem, but my problem is that I need to "convert" the USB signal back to serial to communicate with the XBee. I know that sounds a little strange, but I can't bypass the FTDI due to warranty.

I've found this two solutions but it's not an option because the data logger is configured to run at 921600bps and these run at 115k and 400k max.

Do you guys have any suggestion on what can I do to get this working?

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  • \$\begingroup\$ I don't think the second link (Driver-free USB to asynchronous serial UART interface) would work. It looks like a USB "client" device, not a USB host. \$\endgroup\$
    – DoxyLover
    Sep 4, 2014 at 21:56
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    \$\begingroup\$ How about a 30 dollar computer... A Raspberry Pi or any number of sbc linux computers (OR Routers) with a usb port, configured to either a second FTDI or an actual serial port. As a one off, the price isn't too bad. \$\endgroup\$
    – Passerby
    Sep 4, 2014 at 22:37
  • \$\begingroup\$ Does not the FTDI FT232RL has a proprietary driver, and so proprietary protocol or they adhere to the USB HID standard? You "just" need a micro-controller with the capability of being a USB host. Then implement the firmware to run at the desired baud-rate (a bit high I would say). This is not an off-the shelf solution of course. \$\endgroup\$ Sep 4, 2014 at 22:47
  • \$\begingroup\$ USB-serial devices use the CDC standard, not HID. Any reasonably powerful MCU with a USB2 FS or HS host or OTG port could do this but you'd have to write or modify CDC host drivers to suit the FT232R. The RPi solution proposed by Passerby is about as good as you're going to get I think, it's both simple and inexpensive, relatively speaking. \$\endgroup\$
    – markt
    Sep 4, 2014 at 23:04
  • \$\begingroup\$ What is the MAX baud rate of your XBee? You may have to use something like the RPi that @Passerby mentioned and store the approx 1Meg of logged data on the RPi then transmit it at a slower, more reliable baud rate. \$\endgroup\$ Sep 5, 2014 at 4:27

2 Answers 2

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Finally my only option was use a Linux board with the FTDI driver running on it, I'm using this one: http://acme.systems/arietta

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  • \$\begingroup\$ You don't need a linux-class computer for that. Although it may be easier to get this off the ground and working, a filesystem means yet another component, and in many cases, a potential area of failure. Cleaner, longer-term cheaper solutions would be an embedded controller capable of doing this while running from on-chip flash. \$\endgroup\$ Sep 24, 2014 at 20:41
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Microchip's USB stack has a built-in example for USB CDC Host that can run on their PIC24/PIC32 boards. As do most of the ARM vendors. Though if you're just building a one-off, just get a SBC (Raspberry Pi, Olinixino, et cetera) and run "screen" or something similar.

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