using LPT in ECP-mode

Discussion in 'Windows Vista Drivers' started by Jan Bruns, Sep 24, 2004.

  1. Jan Bruns

    Jan Bruns Guest


    this isn't the best group to ask this question, I guess,
    but I didn't find a better match.

    With Win98se, if I CreateFile(LPT), will it automatically
    choose ECP, if supported by the connected device?
    Furthermore, how to force read/writefile use ECP-DMA?
    Finally, how to send ECP-commands?


    Jan Bruns
    Jan Bruns, Sep 24, 2004
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  2. Jan Bruns

    Jan Bruns Guest

    "Jan Bruns":
    I_ve tested a bit:

    LPThandle := CreateFile('LPT1',...);
    for i:=1 to n do writefile(LPThandle,buff,bufflen,.result,nil);

    doesn't seem to consume any CPU on one machine, but about
    50% on another (for bufflen>1000), both with ECP enabled.
    So it seems to be somewhat hw-dependent, wether or not
    DMA is chosen.

    Bandwidth for n=1000, bufflen=4000 was about
    650kB/s and 440kB/s on an older K6-computer
    for a non-ACKing receiver (periphACK always low,
    so no transaction gurantied...).

    On both systems, writefile(LPThandle,buff,bufflen,...)
    never returns, if bufflen >(4096+38).

    Two bugs + undefined DMA-use. Aua.

    Jan Bruns
    Jan Bruns, Sep 26, 2004
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