From owner-freebsd-hackers  Sat May 20 01:03:38 1995
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Date: Sat, 20 May 1995 18:03:28 +1000
From: Mark Treacy <mark@labtam.oz.au>
Message-Id: <199505200803.SAA26101@labtam.labtam.OZ.AU>
To: freebsd-hackers@freefall.cdrom.com
Subject: Re: Synchronous serial support?
Sender: hackers-owner@FreeBSD.org
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>We are looking for support of synchronous serial using the Zilog Z85230
>chip (or equivalent).  It's title is the ESCC (Enhanced Serial
>Communication Controller).  I am wondering if FreeBSD supports any kind of
>USART (I know that 8250/16x50 UARTS are supported), esp. this one.
The 85230 is basically an 8530 with deeper fifo's.  This part
is supposed to be more suited to synchronous applications.  It isn't
really, the priorities that the 8530 (and hence 85230) assign interrupts
internally mean that the chip is more suited towards async apps than
sync.  The 85230 is software compatible with the 8530, it is also pin
compatible.  It is a horrible part.

>Does anyone out there do synchronous serial in FreeBSD?  I'd like to hear
>some (private, no need to broadcast these) stories about people's
>experiences with the Cronyx-Sigma adapters.
The cirrus logic chip that this board uses seems to be a nice part
for sync apps.

Do whatever you can do to avoid going the 8530/85230 path.

 - Mark.