[rescue] SS Classic Serial ports
Charles Shannon Hendrix
shannon at widomaker.com
Sat Apr 26 14:57:21 CDT 2003
On Sat, Apr 26, 2003 at 01:20:37PM -0500, Scott Newell wrote:
> At 08:00 PM 4/23/2003 -0400, Charles Shannon Hendrix wrote:
> >Now, that's not because the chips are so terrible, but because Sun did
> >odd things in the implementation. They use seperate clocks for in and
> >out, which drift and every N frames cause an error at high speeds.
> Hmmm... Do you mean that Sun ignored the internal baud rate generators on
> the 8530 uarts, and generated separate clocks for the shift registers
> through the RTxCA, RTxCB, TRxCA, and TRxCB pins? I don't think so. The
> uart has a baud rate generator for each channel, and the clocks for tx and
> rx on a single channel are shared. Looking through the OpenBSD source, it
> sure appears to me that the default situation is to use the internal baud
> rate generators.
I'd have to dig up the conversaion from archives, or you could find it
All I can tell you is that some of the guys who hack OpenBSD and NetBSD
serial code said they use seperate clocks, and that's the problem.
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