dougm@pnet51.orb.mn.org (Doug Mcintyre) (06/05/91)
Why are these UARTs so popular it seems, that I see them mentioned all
ofer the place for people looking for them for their pc's?
I'm going to be hacking up a couple serial ports into my machine, and was
wondering what they offer over the 8250 that is standard?
I've seen them offered by a couple mail order places, so that isn't really a
problem getting them, (as it seems nobody else can find them..)
UUCP: {tcnet, crash}!orbit!pnet51!dougm
ARPA: crash!orbit!pnet51!dougm@nosc.mil
INET: dougm@pnet51.orb.mn.org GENIE: D.MCINTYRE1lts@hpcndpc.CND.HP.COM (Lou Schulte) (06/07/91)
> Why are these UARTs [16550] so popular it seems, that I see them mentioned all > ofer the place for people looking for them for their pc's? > I'm going to be hacking up a couple serial ports into my machine, and was > wondering what they offer over the 8250 that is standard? The 8250 buffers just a single byte whereas the 16550 has a multibyte FIFO. So if you have interrupt lockouts exceeding the one-byte transmission time (about 1 msec at 9600 baud) you'll lose bytes with the 8250 but not with the 16550. Also, as I understand it, the 16550 is a direct replacement for the 8250. Lou Schulte
josephc@nntp-server.caltech.edu (Joseph Chiu) (06/08/91)
lts@hpcndpc.CND.HP.COM (Lou Schulte) writes: >> Why are these UARTs [16550] so popular it seems, that I see them mentioned all >> ofer the place for people looking for them for their pc's? >> I'm going to be hacking up a couple serial ports into my machine, and was >> wondering what they offer over the 8250 that is standard? >The 8250 buffers just a single byte whereas the 16550 has a multibyte FIFO. So >if you have interrupt lockouts exceeding the one-byte transmission time (about >1 msec at 9600 baud) you'll lose bytes with the 8250 but not with the 16550. >Also, as I understand it, the 16550 is a direct replacement for the 8250. >Lou Schulte Speaking of UART's, I have noticed that my "AT-Serial Card" does not use 16450/16550's, but rather a chip numbered 82450. I suspect it's supposed to be a relabeling of the 16450 number, but does anyone know for sure? By the way, if anyone is interested, I got this AT I/O card with TWO serial ports, Parallel port, and Joystick port for 14.00; not a bad deal, except the chips are not socketed, so I can't pull out the old UART's to replace it with the 16550. (And a joystick for $10.00, and a mouse for $13.00, and RS-232 tester for $7.00... and on and on... Amazing what happens when you whittle your insomnia by thumbing through Computer Shopper... : ( My $14 purchase grew to almost $90!) -- Joseph -- Joseph Chiu, Dept. of Computer Science, Caltech | Rrr Redundant Tautology System 1-57 Fleming House, Caltech, Pasadena, CA 91126 | Ttt Triplicate Archival Backup Tel/Fax:(818) 585-0393 josephc@coil.caltech.edu | Sss RTS TAB, Model RTS-333-TAB