[Coco] WiFi modem.

[Gene Heskett]

On Friday 19 January 2018 09:59:11 Allen Huffman wrote:

> On Jan 19, 2018, at 8:57 AM, Gene Heskett <gheskett at shentel.net> wrote:
> > I am not in favor of a 6551 unless its a new clone with  hardware
> > flow control fixed. Something the 6551 from NOS can't do.
>
> Can you refresh us on this?
>
> Curtis Boyle was explaining that they used a 6552 for their custom
> boards, and it solved some of the issues.
>
> Still, something that just emulated those registers but had a buffer
> internal would be even better. I keep wanting to just get an Arduino
> mapped in, then I could write all of this. Heh.

We had an aciapak driver 2 decades back, that with a small cut/paste on a 
couple pins of the 6551, allowed the full bi-di use of the 7wire flow 
control protocol. Unforch that fix has been lost in the sands of time, 
and I have never had any luck making the xon/xoff work, mainly due to 
the lack of a single stage, one byte buffer in the rs232 pack. The net 
result, when I want to use the serial cable to move something to the 
coco3, is that I must absolutely set the data window of the linux rzsz 
code to 256 bytes, then wait for the coco3 to send back the crc of that 
256 bytes. This results in an error free transmission rate on a 6309 
coco3 of around 620 bytes a second, and about 470 on a stock coco3. This 
at the 6551's maximum of 9600 baud, or 960 chars a second and using 
7wire flow control. But apparently, in the mad dash to modularize 
everything, using up system ram and preventing the formatting of a new 
floppy, all that code to effect the pin swap on the 6551 was thrown out. 
Along with the amiga I was using as a gateway. Problem undiscovered here 
until development was moved to linux/winblows, which was what, 10+ years 
later?  And I'm getting on, so the chances of me fixing that are 
vanishingly small.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>