Re: [PARPORT] ECP, DMA, driver writing

From: Derek Bouius (dbouius@abio.com)
Date: Fri Jun 23 2000 - 11:35:34 EDT

  • Next message: schilling@fokus.gmd.de: "Re: [PARPORT] ECP, DMA, driver writing"

    I have modified the parport user space driver to do hardware ECP, DMA
    read.
    (Using 2.3.99pre8 and just copying the DMA write concept)
    It is not pretty (i'm a hardware guy) but I can post it if you want it.

    Even with the user space driver, the ECP/DMA concept is interrupt driven
    in terms of waiting for the terminal count (TC), but I am not sure how to
    extend the DMA size past the 64K bytes.

    I found the throughput to be quite fast (about 1 byte/ usec) but there is
    never guarenteed servicing... ie. the task can be swapped out of priority
    for about 50 usec. I needed guarenteed throughput so I am using EPP with
    user defined extra handshaking.

    Hope this helps and if you have more questions ask away,
    Derek 

    --
Derek Bouius     | American Biometric Company  | Tel:(613)736-5100x281
dbouius@abio.com | 3429 Hawthorne Rd,Ottawa,ON | Fax:(613)736-1742

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