[rescue] Parallel ports [was Re: Slightly OT: ?Bad Cap Saga]

Geoffrey S. Mendelson gsm at mendelson.com
Thu Aug 21 15:05:54 CDT 2008

On Thu, Aug 21, 2008 at 03:29:17PM -0400, der Mouse wrote:
>If someone has a real USB parallel-port interface, as opposed to a USB
>printer interface that speaks parallel-port printer protocol out the
>printer end, I'd be interested.  (It would still be substantially less
>convenient than a real parallel port, but it probably would have uses

I have no idea if this would be of any help, but both IDE (PATA) and
SCSI are parallel ports. I'm sure they have some sort of handshaking,
which might make your work a lot harder. 

Siverlining, a third party Mac SCSI driver package had an option of
using timiming loops, I have no idea if a PC SCSI port could be used
that way. 

>This goes back to my remark about the difference between a parallel
>port and a printer interface that happens to speak parallel-port
>printer protocol.

There are lots of development boards with real parallel ports instead
of a printer port, except for cost, why not use one of them?

>I think you'd also have trouble finding a serial port that could run at
>parallel-port speeds.  My ROM reader can grab 64KB of ROM contents
>through a parallel port faster than you can send 64KB over a 115.2Kbaud
>serial line (I think - it's been a while since I tried it, but I think
>it's only something like two to three seconds).  And that's with a
>completely clockless flying-wire rat's-nest breadboard circuit.  The
>serial-line version requires substantially more complexity (at least a
>UART, implying a clock, and probably some kind of microcontroller).

If this is what you want to do with it, you don't need a particularly
fast computer. There are plenty of PIII computers with printer ports on
them, you could probably get a 10 year supply for the asking on any
of the free mailing lists (freecycle, Craigslist, etc), assuming you
had to nurse them along and they would not last much more than a year. 

To be honest the last time I owned a ROM reader/writer it had an 8 bit
ISA card interface, but aren't there USB ones on the market? 

Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM

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