[Coco] serial port problem

[Aaron Wolfe]

On Oct 31, 2013 10:25 PM, "Mathieu Bouchard" <matju at artengine.ca> wrote:
>
> Le 2013-10-31 à 19:36:00, Bill Pierce a écrit :
>
>
>> Mathieu, Drivewire uses special software and protocol to run the Coco at
115200 baud.
>
>
> Well, it's so special, that I don't even know whether it uses the cable
at all. I downloaded hdbdw4cc3 onto the CoCo using CLOADM:EXEC, and started
DW4 on the Linux machine, but now all I get when I DIR from the CoCo is ?IO
ERROR.
>
> BTW the port detection problem is fixed already : I had to change
permissions on /dev/ttyS0 (COM1).
>
>
>
>> This is why I say old baud rates do not apply. You do not "set" the baud
rate for dw4 on the Coco. That is done in hdbdos and Os9 drivers. Leave the
baud rate at the default value.
>
>
> Look, the reason for using Terminate and UltimaTerm is to test that the
cable is able to talk at high enough speeds to make it likely that
Drivewire would work. With the above setup, I don't know what's going on.
>

The trouble you see in those terminal programs at higher speeds is most
likely a red herring.  Cables that work at any baud rate will very often
work at all rates.. nature of the beast.  When serial cables do fail at
higher speeds it isn't usually an all or nothing situation, much more
common to see sporadic problems, especially when lots of data is being
transferred.

In all the time I've been supporting drivewire, we have never had a cable
that just didn't work at DW speeds.  We have had a few cables that would
cause CRC errors now and then when doing full sectors of data. The
resolution was always to shorten the cable.

There are a wide variety of troubleshooting tools built into the drivewire
software.  These will provide much more accurate information than tests
with terminal programs will.  Before worrying about that, can you double
check that your cable matches this specification?

http://sourceforge.net/apps/mediawiki/drivewireserver/index.php?title=DriveWire_Specification#Physical_Interface_Requirements

> On the CoCo3 in HDBDOS 1.4 DW, I also tried this :
>
> DRIVE OFF
> BACKUP 0 TO 4
> ?IO ERROR (after a few seconds of reading nonvirtual drive 0)
>
>
>  ______________________________________________________________________
> | Mathieu BOUCHARD ----- téléphone : +1.514.383.3801 ----- Montréal, QC
>
>
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