Re: OT: DOS programming EPP

On Sun, 22 Jan 2006 03:14:06 GMT, Robert Baer
<robertbaer@xxxxxxxxxxxxx> wrote:

> I have done a websearch, and there is nothing available that
>eXplicitly shows how to program a parallel port in the EPP mode, and how
>to *safely* interface with it.
> The best (incomplete) source i found was on the beyondlogic.org site.
> However, no matter what i do, the nominally input printer pins (pin 1
>= strobe, pin 13 = select and pin 15 = error bar) act like outputs.
> Data lines when low safely sink 2mA (did not try more as i did not
>want to zap the MB) R=45 ohms, and when high safely source 1mA (did not
>try more R=2.2K).
> "Strobe" line pin 1 was always high and safely sink 1.5mA R=730 ohms.
> "Select" line pin 13 was always high and safely sink 1.0mA R=2.2K.
>
> There seems to be *no* specifications or equivalent circuits for the
>parallel port as implemented on the ASICs used in modern PCs.
> Therefore, it is completely unknown as to the maximum safe sink
>current to a logic low pin or the maximum source current from a logic
>high pin.
> It is not wise to force a pin that is acting as an output, into the
>opposite state; so the info is necessary for safety.
>
> I want and need to program this in DOS.
>
>** as an aside, it was interesting to see that when Windoz booted after
>my fiddling, that i saw "detecting new hardware" etc.

Go back to the beyond logic page and read the parallel port FAQ from
the beginning. The EPP page assumes you did. You need to set up the
extended control register (BASE + 0x400). In EPP mode Strobe is the
WRITE/NOT READ bit and an output.
I think you need to do some C or BASIC code to do any of this. I don't
think you can just use DOS shell commands.

Paul C
.

Relevant Pages

  • Re: OT: DOS programming EPP
    ... >>eXplicitly shows how to program a parallel port in the EPP mode, ... >> However, no matter what i do, the nominally input printer pins (pin 1 ... >>parallel port as implemented on the ASICs used in modern PCs. ... > think you can just use DOS shell commands. ...
    (sci.electronics.design)
  • Re: OT: DOS programming EPP
    ... >>>eXplicitly shows how to program a parallel port in the EPP mode, ... >>> However, no matter what i do, the nominally input printer pins (pin 1 ... >> Paul C ...
    (sci.electronics.design)
  • Re: OT: DOS programming EPP
    ... There seems to be *no* specifications or equivalent circuits for the parallel port as implemented on the ASICs used in modern PCs. ... it is completely unknown as to the maximum safe sink current to a logic low pin or the maximum source current from a logic high pin. ... The EPP page assumes you did. ... This way of programming was used by the old "standard" printer interface. ...
    (sci.electronics.design)
  • Re: OT: DOS programming EPP
    ... >>> parallel port as implemented on the ASICs used in modern PCs. ... >>> to a logic low pin or the maximum source current from a logic high pin. ... The EPP page assumes you did. ... This way of programming was used by the old "standard" printer interface. ...
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