[Coco] DriveWire 3

[Roger Taylor]

Boisy, since DW3 is not a sale product I decided to bring this to 
your attention on the list like everyone does with my software 
issues.  It tends to help to get a collection of opinions.

First, let me mention that I sell HQ bitbanger cables.  I test them 
not only at 115200 bps, but at twice that speed using a certain 
person's unannounced bitbanger routines.  Not only that, but my 
cables are tested using an IOGear USB to Serial adaptor.  With that 
being said, I doubt that my cables are the reason I'm having trouble with DW3.

What I've found is that it doesn't take much to throw some USB serial 
adaptors out of sync or to crash them.  CoCoNet bitbanger does 
neither, nor taps into any special tricks with such an adaptor.  I'm 
simply opening the COM port and talking over it but with precise 
timing of the bitstream.

After looking at your DW3 source code, it appears that your order of 
alternating cycle counts of 15 and 16 could be a problem.

It appears that your order of alternating cycles to RECEIVE bits are:
15,15,16,15,16,15,16,16
__ __ -- __ -- __ -- --

I drew the dashes and underscores to better visualize the 
pattern.  Your transmitting routine's cycle pattern appears to be different.

The best approach I've found after trying tons of different patterns 
was to use 15,16,15,16,15,16,15,16 for both Receive and Trasmit 
routines.  This has proven to work almost flawlessly (I say almost 
because there's no such thing as flawless) and I've run tests for 
days straight with no CRC errors counted, over both a motherboard COM 
port and a USB to Serial adaptor, two latops and an old Win98 tower.

You'll get even MORE stability by using the 8-N-2 protocol.  The 
extra bit of timing is worth it.  Throughput means nothing if the 
connection is going to barf out every 1 attempt out of 10.

For me right now about 1 or 2 out of 10 attempts in DriveWire 3 
results in an error.  For example, I can be sitting at the NitrOS-9 
prompt and type "dir" and get an error #244, type "dir" again and get 
error #216.  Finally, a third "dir" spits the directory out.  Almost 
always a "dir /x1" on the first one or two tries results in an 
error.  Sometimes but rarely the .dsk image crashes during boot.

Again, IMHO, since DW3 is free I saw no harm in talking about these 
things on the list as opposed to stepping on a sale product.  My 
biggest question is whether or not anybody else is having the 
occasional errors with DW3 and what brand of USB adaptor they might 
be using, etc.  But another question is why all of my bitbanger 
cables work fine with CoCoNet but not DriveWire using the same 
bitbanger cable wiring.

If there are other coders now improving on DriveWire, I think the 
above 2 timing suggestions should do the trick.

Why am I using DW3?  I'm working on building a wirelessly bootable 
NitrOS-9 .dsk image to add to my test cases.  Nothing major, just 
typical lab work.

-- 
Roger Taylor

http://www.wordofthedayonline.com