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- Path: sparky!uunet!mcsun!sun4nl!hacktic!utopia!fangorn!root
- From: root@fangorn.hacktic.nl (Root Account)
- Newsgroups: comp.dcom.modems
- Subject: Re: Can I upgrade a 16450 uart to a 16550a?
- Message-ID: <7Z97wB5w165w@fangorn.hacktic.nl>
- Date: Mon, 11 Jan 93 05:24:53 GMT
- References: <1993Jan7.152939.28987@wam.umd.edu>
- Organization: Fangorn System
- Lines: 50
-
- joel@wam.umd.edu (Joel M. Hoffman) writes:
-
- > I just purchased a high speed modem (14.4K from Boca) for my Dell
- > 325D. I was almost sure Dell would have put a good uart in the
- > machine, but it turns out it's only a 16450. Naturally, I'm losing
- > char.s with high-speed transfers, especially with a loaded machine
- >
- > Is it possible to upgrade the 16450 to a 16550a? (I assume that will
- > help the problem; correct me if I'm wrong.)
-
- It will.
-
- > [I tried asking the representative a Dell, but, when he answer my
- > question of "What kind of uart is in the machine" with "You have a
- > VLSI chip," I gave up.]
-
- A VLSI chip can mean two things : That the chip you have is some Very Large
- Scale Intergration job, which holds, for example, the COM port, LPT port and
- drice con's. In which case you can't do nothing about the chip. You'll have
- to buy yourself an extra serial card with socketed 16450's that you can
- replace or buy one that has the 16550 to start with (then there's no need to
- replace anything). That's the most likely thing....
- It can also mean the computer has the VLSI chipset on the motherboard, that
- has nothing whatsoever to do with your COM port.
-
- So basically : Just open the machine. Check if the COM port is in some VLSI
- chip (very large scale.....) (Which is a small (usually about less than 1*1
- inch), multi-legged device, usually SMD (surface mount, those damn' small
- legs that are soldered to the component side)) or a real 16450 (AKA 86450,
- AKA 16?450) or 8250 (even older than the 16450). It's easy to find : a 40-
- pin DIL (Dual In Line) chip, with legs that are real pins that point down...
- (about 0.6*4 inch) If you find this, check if it's in a socket so you can
- just pull it out, or if it's soldered to the motherboard.
-
- If it's a VLSI, you can't do nothing. Just buy an extra serial card and
- either set it as the next COM port(s) or disable the ports on your
- motherboard. If it's a soldered 16450, then again you have to get an extra
- card (Well, if you REALLY REALLY have to, it is possible to desolder... I
- wouldn;t advise that, however, and let someone experienced do it...) If it's
- a socketed 16450, you're in luck : Get yourself a 16550 AFN (NOT the A, it's
- no good. You really need the AFN), pull out the 16450 (carefully !) and push
- the 16550 AFN in (again : carefully), the same way the 16450 was in. (check
- the indenture or spot on one of the short sides).
- _____ _____ ____________
- |1 \/ 40| 1 |o | 40 Top view, numbers are pin numbers.
-
- Good luck,
-
- bram smits
-
-