Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!hplabs!hpda!hpcupt1!glowell
From: glowell@hpcupt1.HP.COM (Gary Lowell)
Newsgroups: comp.dcom.modems
Subject: Re: throughput using CTS flow control on a Trailblazer+
Message-ID: <6810002@hpcupt1.HP.COM>
Date: 21 Apr 88 22:03:28 GMT
References: <871@spdcc.COM>
Organization: Hewlett Packard, Cupertino
Lines: 23


     I am using a TB+ on a 286 based system, and of course the TB+ can
     easily overwhelm the CPU.  I am working on building a simple
     Serial Card and writing my own driver for it.  Several chips 
     have been mentioned here that will provide flow control on 
     CTS without involving the host.  Are there any chips that 
     provide similer features for RTS flow control, which I believe
     the TB+ supports ?  I want to make sure that regardless of
     the data-rate, I won't lose any characters if the CPU's not
     keeping up.

     The next step after that is to see what I can do to improve
     the throughput.  The most obvious way I see to do this, is to
     not interrupt the CPU on each character.  Adding an onboard
     uP to the serial card makes it not simple and I'd like to avoid
     that at this point.  However, some serial chips have FIFO's, 
     do DMA, etc.  Can anyone provide pointers as to what features
     are useful for improving throughput, and how I might write a
     driver that would take advantage of them ?

     Thanks in advance.

     Gary Lowell
     {uunet,hplabs}!hpda!glowell