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Article #8340Re: AMD 8251 (USART) Info?
From: Bob Haar CS50
Date: Tue, 13 Nov 1990 20:09
Date: Tue, 13 Nov 1990 20:09
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In article <60822@bbn.BBN.COM>, gonzalez@bbn.com (Jim Gonzalez) writes: |> I am in the process of getting a Northstar HSIO (serial interface) board |> working on a Cromemco System Three (S-100 bus with a Z-80). The CPU board |> apparently produces a 4MHz clock, while the serial board expects to be |> clocked at 2MHz. I could adjust the baud rate specification by a factor |> of 2 (yielding 1200 baud when I tell it to run at 600, for example), except |> the 8251 is only rated to run up to 2.4MHz. I am not familiar with the Cromemco system 3 board, but try to get a listing of it's bus signals. Many of the 4 and 6 MHz Z-80 CPU boards for S-100 systems used one of the "unassigned" pins for an alternate clock. This is because many peripheral cards needed a 2 MHz clock. If there is one, just jumper the clock input to that bus pin. Bob Haar CSNET: HAAR@GMR.COM UUCP: uunet!edsews!rphroy!rcsrlh!rhaar Computer Science Dept., G.M. Research Laboratories DISCLAIMER: Unless indicated otherwise, everything in this note is personal opinion, not an official statement of General Motors Corp.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!caen!rphroy!rcsrlh!rhaar From: rhaar@rcsrlh.GMR.COM (Bob Haar CS50) Newsgroups: sci.electronics Subject: Re: AMD 8251 (USART) Info? Message-ID: <37880@rphroy.UUCP> Date: 13 Nov 90 20:09:59 GMT References: <60822@bbn.BBN.COM> Sender: news@rphroy.UUCP Reply-To: rhaar@rcsrlh.GMR.COM (Bob Haar CS50) Lines: 18