Re: FTDI chip USB-RS232 - Marcus do you know a brand that contains it? Message #21 Posted by sylvandb on 11 July 2011, 9:35 p.m., in response to message #20 by Cody
Quote:
This is the cheapest adapter I found on Amazon that specifically lists the FTDI chipset:
"Mini Adapter has one Status LED and uses FTDI Chip for up to 230K Speed."FTDI adapter
Notice anything different about that compared to the ones I listed?
Unfortunately that one and many others I've seen on Amazon all are specified to do a conversion to RS-232 voltage levels (-5v to -12v and +5v to +12v) which may or may not work and may or may not fry the 3.3v (0v and 3v) signaling used by the calculators. It seems like it would be cheaper to not do the conversion but quantities of scale...
Adding "header" to the search does turn up: USB to 3.3v TTL Header like FTDI TTL-232R-3V3 with a description that claims "Utilizes newest FTDI FT232QR chip"
With that said, sometimes the cheap ones don't actually do a conversion to RS-232 voltages... (Which violates the RS-232 specification, but much RS-232 hardware does work and recognize the signals never the less.) I just cannot recommend anything like that, because you are relying on not only unspecified feature, but a feature contrary to the specification.
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