[Linux-parport] True Parallel Port Interface for Bit-banging?

Jan Kandziora jjj at gmx.de
Tue Oct 25 22:20:46 PDT 2016

Am 26.10.2016 um 02:04 schrieb Maciej S. Szmigiero:
> I have tried dosemu, dosbox and as far I remember also VirtualBox
> with an old, DOS car service app.
> Wasn't able to make it communicate until I booted true DOS.
> That machine had old-style ISA serial ports so it was possible.
This is because it most likely uses the K-Line protocol, which needs to
output two bytes at 5 (in words: FIVE) baud at the very beginning of
each package.

It's no possible to have such a bitrate through any standard driver.
Those old car service apps tweak the UART hardware heavily to output
that signalling. It literally needs a 8250 chip. May even fail with some
SuperIO "16550" emulations in current mainboards.

Newer cars have CAN, but these K-Line cars (up to model year 2005 I
think) can give you headaches.

Kind regards


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