[PARPORT] read data using ppdev in EPP mode

From: Myunghyun Lee (mhyun@sollae.co.kr)
Date: Wed Mar 20 2002 - 00:29:26 EST

  • Next message: Tim Waugh: "Re: [PARPORT] read data using ppdev in EPP mode"

    I am developing a system.
    The system uses Winbond's W99200F(MPEG-1 video encoder).

    I use a Linux machine whose kernel version is 2.4.7-10.
    I found out "The Linux 2.4 Parallel Port Subsystem" in Internet.

    I wrote a program "User-level device driver".
    And I succeeded negotiate with W99200F.
    I read W99200F's information like below.

    mode = IEEE1284_DEVICEID;
    ioctl(fd, PPNEGOT, &mode);

    MFG:Winbond;MDL:W99200F;CLS:MEDIA;DES:WINBOND VIDEO ENCODER;

    But I cannot read register value from W99200F.
    Following is a read sequence.

    I negotiated to EPP before.

    set data direction to OUTPUT
    set all control lines to HIGH
    output address
    set [Write] and [Address Strobe] to LOW
    wait until [Wait] is HIGH ------------> Wait isn't changed to HIGH
    set [Write] and [Address Strobe] to HIGH

    set data direction to OUTPUT
    set [Write] and [Data Strobe] to Low
    wait until [Wait] is HIGH ------------> Wait isn't changed to HIGH
    read data
    set [Write] and [Data Strobe] to HIGH

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     Myunghyun Lee mailto:mhlee@eztcp.com
     Sollae Systems Co., Ltd. http://www.eztcp.com
     TEL:+82-32-437-2346, FAX:+82-32-437-2347
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