usb-to-parallel port solutions

Chris Elmquist chrise at
Fri Nov 6 17:11:23 CST 2015

On Friday (11/06/2015 at 11:10AM -0500), Douglas Taylor wrote:
> On 11/5/2015 9:08 PM, Chris Elmquist wrote:
> >On Friday (11/06/2015 at 01:51AM +0000), dave at wrote:
> >>Can somone recommend a good USB-to-parallel port solution that will easily
> >>work with Linux?
> >FT245??
> >
> >
> >
> >Will look like a tty device to Linux(/dev/ttyUSBn) but baud rate, other
> >settings are ignored and whatever you write to that port comes out the
> >FT245 bit parallel and whatever you strobe into FT245 bit parallel comes
> >out the tty driver on the top side.
> >
> >I have used these as a high speed channel to vintage machines such as
> >Heath H89 and then we ran a disk emulation protocol on top of that.
> >
> >Chris
> I'm interested in this, but on the parallel side is it 5V logic? How do you
> connect to the pads?  Does USB provide all the necessary power?

On my original prototype, I soldered .1" headers into the pads or holes
of the Sparkfun board and then then those go through the holes in .1"
"Vector Board".  I'm pretty much old school with prototyping--  point
to point wiring, soldering each connection-- so there is no wire-wrap
or PCB involved.

Refer to the schematic also there on the Sparkfun page but you can choose
whether the FT245 is powered from the USB side or from the "other" side.
If powered from the other side, then you can decide whether the I/O is
5V or 3.3V.   Actually, you can also decide this even if powered from
the USB side as the device has an internal 3.3V regulator so will supply
3.3V from the 5V USB power.

Chris Elmquist

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