How disable attachment of sio(4) driver to device?

[Daniel O'Connor]

On Sat, 22 Oct 2005 21:48, Bernd Walter wrote:
> That's the big win with 9 bit.
> Modbus uses 8 bit so each controller has to actively listen.
> The RTU variant uses fixed idle times to mark packet ends, which is
> hard to do right in kernel and unreliable to do from userland.
> Since I needed multi-OS support and have at least one customer with
> many busses the kernel was no option.

Fair enough. Your solution sounds very flexible and useful!

> Don't know about line discipline abilities, but I remember that some
> trustfull persons declared this to be doable.
> It is the whole hardware design that won't fit.
> As long as timing is not critical and you have legacy serials it is OK.
> But many USB uarts don't have native 9 bit support as well, and the
> nature of USB is that you really want large FiFos.
> This is a dead track IMHO.

Yeah, I think the line discipline approach is feasible with legacy hardware, 
but USB makes it difficult to do.

> The whole thing is suboptiomal.
> Today there are no reasons to not offload the tricky parts into
> external devices.

Heh, apart from dev time :)

> I'd originaly used Atmel Mega8 plus Philips PDIUSBD11 for this.
> It was a slow but reliable and cheap combination, but Piliphs stopped
> production of the chip.
> Today I use Mega64 and PDIUSBD12 for USB and Mega128 with RTL8019AS for
> Ethernet, which gives me two UART for use in a single device.
> The controller have 9 bit wide FiFos.
> If you are already in the 8051 world, you might look at TI TUSB3410.

Ahh looks interesting. I have used Atmel a bit to play around with it.. I have 
some sample 3410's but haven't even assembled the test board I made :-/

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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