Article View: comp.sys.atari.st
Article #34326Re: Networking, ST's and Spectre 128
From: Jwahar R. Bammi
Date: Fri, 30 Sep 1988 20:57
Date: Fri, 30 Sep 1988 20:57
24 lines
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1786 bytes
In article <3602@druhi.ATT.COM>, dlm@druhi (Dan Moore) writes:
>
> If you have an SCC connected to the STs cartridge port it can
>not be interrupt driven, it must be polled by the CPU on a regular
>basis so that it can detect incoming data. So you need to setup one of
>the hardware timers to interrupt the CPU 28K times per second (actually
>it needs to be at least 50% faster than that in order to be sure no
>data is lost) so it can check if a data byte has arrived and if it needs
>to feed the transmitter another byte. This would occur *ALL* of the
>time, whether or not the AppleTalk link is active. This would slow down
>the Spectre 128 a lot, maybe even make it unusable.
>
Well thats true if you take the Apple `lets do everything in
software' approach. The other alternative is to use buffers from/to
which the CPU can transfer data as needed. In fact, it is conceivable
that all the packetiztion etc be done by a simple processor, and then
shipped thru the cart. port., a packet worth at a time, or at some
appr. granularity.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!mailrus!ukma!cwjcc!bammi@dsrgsun.ces.CWRU.edu From: bammi@dsrgsun.ces.CWRU.edu (Jwahar R. Bammi) Newsgroups: comp.sys.atari.st Subject: Re: Networking, ST's and Spectre 128 Message-ID: <103@cwjcc.CWRU.Edu> Date: 30 Sep 88 20:57:57 GMT References: <YXC6Ity00XoBI940VJ@andrew.cmu.edu> <3602@druhi.ATT.COM> Sender: news@cwjcc.CWRU.Edu Reply-To: bammi@dsrgsun.ces.CWRU.edu (Jwahar R. Bammi) Organization: Case Western Reserve University Lines: 24 In-reply-to: dlm@druhi.ATT.COM (Dan Moore)