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Thread: Full speed serial to dc isa card (a.k.a. DcXfer)

                  
   
  1. #1
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    Default Full speed serial to dc isa card (a.k.a. DcXfer)

    Semicolo has posted this news over at CSV Forums [br][br] Hi everyone, I'm currently working on a modified serial isa card that is able to acheive the dc top speed of 1562500 bps. [br][br]See http://semicolo.free.fr/Dreamcast/xfer/index.html for details. [br][br]My card is now working up to 520 kbps, I'm waiting for a new chip to go higher. (in fact the card is ok, it's my coders cable that's limited to 520 kbs) [br][br]Lets hope this becomes a reality

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    An interesting development, that would have been awesome a couple of years ago. But now, this is way better. Once he gets the problems ironed out, it will be just as fast, and it won't require you to have an ISA slot. Just a USB port. I mean, the last computer I had with an ISA slot was a Pentium MMX 166.

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    Little confused here, all modern PC's can do at least 230/460Kbit off the serial, most rs232 converter are also capable of of that speed.. anywhere I can download dc-tool/dcload with 230/460/921k support opened?

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    Not so simple Kamjin.

    First only 230 kbbps could be used (the dreamcast can't do 460k / 921k, it's stuck to 1562k, 781k, 520k, 390k and slower. The transfer rates are too different)

    Second, the serial ports are configured at 115k top speed even if they can do more, there are some hacks under linux to activate higher speeds, although it doesn't seems very easy (or even documented) to do so.

    My coders cable built with a standard transceiver goes up to 520kbps, I'm waiting for a faster one.

    I know isa cards aren't very new, it was the cheapest way for me to have a full speed serial card (I had one in stock). This mod could be adapted to pci serial cards too.

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    [quote author=semicolo link=board=hardware;num=1096997596;start=0#3 date=10/07/04 at 05:35:01]Not so simple Kamjin.

    First only 230 kbbps could be used (the dreamcast can't do 460k / 921k, it's stuck to 1562k, 781k, 520k, 390k and slower. The transfer rates are too different)

    Second, the serial ports are configured at 115k top speed even if they can do more, there are some hacks under linux to activate higher speeds, although it doesn't seems very easy (or even documented) to do so.
    [/quote]

    Didn't think of that.. need to make your own drivers to properly set the rate.. at least 230K would be better than nothing..

    My coders cable built with a standard transceiver goes up to 520kbps, I'm waiting for a faster one.
    Dallas used to give out samples, good place to get some of the higher speed devices (if that's not where you're getting from now *8) )


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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    I asked for free samples at Maxim's (thanks for the info for Dallas doing the same )

    For info, I tried to set the serial speed at 230kbps adding in the source code the B230400 flag defined in the headers (there already was B115200, B57600 etc..), but it simply didn't worked. One really need to configure the serial port to high speed before using it.

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    Ok, I received my samples (in fact Dallas and Maxim are just one company now).
    I made my new rs232<->ttl adapter and ... It works perfectly !
    Here's what I got from my modded dc-tool version with the uncompressible 4 megs file:
    781250 bps : 55 seconds
    effective: 76522.357979 bytes / sec

    1562500 bps : 30 seconds
    effective: 143419.745389 bytes / sec

    I tried my md5 program too in order to check if transfer is error free and it's ok.

    Note that for 1.56 Mbps, I had to shorten the wires for the cable to work.
    (in fact, the max3225 I used is only garanteed up to 1 Mbps, so it's pretty good).

    I'll update my web pages, next will be to clean the dc-tool code and make a patch available.

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    Default Re: Full speed serial to dc isa card (a.k.a. DcXfe

    Send me the patch and I'll integrate it into the dc-tool portion of dc-load serial CVS.
    Axlen was here... or was he? Bwahha ha ha ha ha...

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