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From: george@wombat.bungi.COM (George Scolaro)
Newsgroups: comp.sys.nsc.32k
Subject: Re: SCN2681 DUARTs
Message-ID: <9011121511.AA04945@wombat.bungi.COM>
Date: 12 Nov 90 22:11:13 GMT
Sender: news@daver.bungi.com
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Approved: news@daver.bungi.com

[In the message entitled "SCN2681 DUARTs" on Nov 11, 16:42, Phil Nelson writes:]
> 
> Hi,
>   I was looking over the information on the SCN2681s and how they
> are configured in the pc532 and I discovered something that I
> wondered if it was really true.  By the documentation I have, it
> looks like the following control signals are connected to the input
> and output ports in the following way:
>     RTSA OP0
>     RTSB OP1
>     DTRA OP2
>     DTRB OP3
>     RxRDYA OP4
>     RxRDYB OP5
> 
> (Notice the alternating Port A on even OP and Port B on odd OP.)
> And then...
>     CTSA IP0
>     CTSB IP1
> **  DCDB IP2
> **  DCDA IP3
> 
> Is it really wired that way or are the schematics wrong or are my
> documents that describe the pinout for the 2681 wrong?

Yes this is correct. The 2681 allocates IP2 and IP3 as general purpose
inputs. I just used them any old how. As Dave mentions to me, this makes
it a tad harder on the software - but then he agreed with my allocation
in the first place! maybe he wasn't listening to me then...

Note that the schematics are 100% representative of the PCB - the netlist
was used to route the board and was then back annotated (to the schematics)
and checked again.

best regards,

-- 
George Scolaro
george@wombat.bungi.com                [37 20 51 N / 122 03 07 W]