Date: Tue, 02 Jul 96 10:32:07 PST From: "Brett Glass" <Brett_Glass@ccgate.infoworld.com> To: Bruce Evans <bde@zeta.org.au>, bde@zeta.org.au, hdalog@zipnet.net, msmith@atrad.adelaide.edu.au Cc: Kevin_Swanson@BLaCKSMITH.com, chuckr@glue.umd.edu, freebsd-hardware@FreeBSD.org, jparnas@jparnas.cybercom.net Subject: Re: muliport boards - building a PPP dialup server Message-ID: <9606028363.AA836328145@ccgate.infoworld.com>
next in thread | raw e-mail | index | archive | help
> If the UART's fifo is larger than about 128, then the pseudo-dma buffers > won't be able to take all the input. Flow control may fix the problem in > practice (just like it does for a modem with a bug buffer connected to a > UART with a small fifo). This brings up a problem I'd forgotten about: slow modem response to flow control signals. Often, the modem's internal firmware gives flow control such a low priority that several hundred characters can escape before a dropped "Clear to Send" signal is recognized. A UART with a big FIFO can help, especially if the UART does not have automatic flow control. --Brett
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9606028363.AA836328145>