USB ppbus?

[George Mitchell]

On 12/20/16 13:41, Ian Lepore wrote:
> On Tue, 2016-12-20 at 13:15 -0500, George Mitchell wrote:
>> [...]
>> Thanks for the response.  I think I could kludge the ioctls I want
>> into
>> ulpt.c by learning more about the USB system works.  Possibly.  On a
>> good day.                                                    --
>> George
>>
> 
> IMO, ppbus solves a 1990s problem that we don't much have anymore:
> multiplexing multiple concurrent (or time-slice-shared) users of a
> single parallel port that may have multiple non-printer devices daisy-
> chained on it.
> 
> If the only thing you're looking for is the ability to treat some of
> the DB25 pins as gpio pins, just adding the ioctls to ulpt.c might be
> the way to go.
> 
> Another possiblity, if all you're after is gpio on the end of a usb
> wire, is to use an FTDI usb-serial adapter and then use either the
> existing ioctl() interface in the uftdi driver (see uftdi(4) manpage),
> or libusb and libftdi (I'm not sure the latter has ever been ported to
> freebsd).
> 
> -- Ian
> [...]

Thanks.  I need the DB25 Centronics interface on the end of a USB wire,
so I guess I'll learn more about the USB system.

Musing: Has any other presently defunct company exerted such an
influence on computer interfacing over the years than Centronics Data
Computer Corporation?  (Yes, I know they defined the 36-pin "blue
ribbon" interface, and that IBM promulgated the DB25 connector for it,
but electrically it was the Centronics interface.)         -- George