[Coco] RS232 Pak needed

[Gene Heskett]

On Friday 20 September 2013 12:57:54 Steve Bjork did opine:

> We can do a limited hardware compatibility so most of the Non-OS-9 stuff
> will run.  For OS-9 drivers, we can added a bit more stuff to speed up
> the CPU to RS-232 handshaking. (Like current size of data in the FIFO
> buffer.)

I like what I'm hearing Steve, but because the 6551's hardware control is 
busted, the hardware flow controls need to be completely hidden in the pic 
code.  What currently exists in sc6551.dr is a deadlock if its ever 
triggered.  Been there, done that, uncountable times so I have to use a 
very restricted "window" size of 256 bytes when using the linux zmodem to 
send a disk image to the coco with both ends set for 9600 baud.  The crc 
checking and handshaking slows it enough it just pours down the pipe.  Its 
a very small bore pipe but it works.

> I would also like to see a large (about 500 to 1,000 byte) FIFO buffer
> with RS-232 control line handshaking done right so we can speed up the
> I/O.  There are Pic chips with that size of ram and still cost only
> $0.75 or so.

How about program flash, something we could move a flea clip or dip sw and 
program directly from the coco to update the pics operating code?  How much 
flash is in this seventy five cent pic?

If we take rzsz out of the picture, and treat it as an address with an IRQ 
to indicate data is ready to be read, how fast is the existing sc6551.dr?  
Way faster than 9600 thats for sure, but is 115200 within reach?  I don't 
know since this 6551 is such a slow poke anyway.

> Steve
> 
> On 9/20/2013 5:22 AM, Brian Blake wrote:
> > Gene,
> > 
> > Are we talking about something that would only be usable in
> > NitrOS-9/OS-9 or would in maintain compatibility with RS-DOS as well?
> > Either way, I'm in since as soon as  can get a handle on all this
> > stuff buzzing around with NitrOS-9 I'm gonna be tackling that.
> > 
> > 
> > Brian
> 
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Cheers, Gene
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