From: Paul Khoury (pkhoury_at_loop.com)
Date: Mon Dec 08 1997 - 20:22:05 EST
On Mon, 8 Dec 1997 21:23:40 -0800 (PST), Steve Parker wrote:
>On Mon, 8 Dec 1997, Paul Khoury wrote:
>
>> I think that the 16450 adds buffering or some little feature to the
>> 8250, and the 16550 has more improvements, and FIFO.
>
> The 16450 was a slightly faster version of the 8250. The 16550 added a
>16-bit FIFO buffer.
Are you sure, or did you mean 16 byte? Because it will also
work on 8 bit cards.
>
>> Also interesting
>> is that you can take off the 8250 or 16450 on older I/O cards and replace
>> it with a 16550, because they operate exactly the same, but software
>> determines whether you can use the advanced features of the 16550 or
>> not.
>
> I've done that with a few IO cards. Unless they are socketed it is
>hardly worth it.
Well, yea. I use an 8250 for my mouse, and a 16550 for my 9600 bps
modem. Too bad I can't use my Home & Away on my server, though.
I've desoldered 8250's and 16450's from a few IO boards,
>installed sockets and stuck in 16550's. It mattered a lot more about 3-7
>years ago when I mainly had '386 and '486 boxes and IO boards with 16550's
>were both expensive and hard to find.
>
> Having a good desolder station makes it practical. Not having one makes
>it fairly difficult.
Well, I know how to solder, but I'm not too good at it.
>
> Nowadays you can also get a 16650 which increases the buffer to
>32-bytes. This helps at 230.4Kbps and 460.8Kbps speeds and higher. They
>no longer use the same pinout and usually have 2-4 ports worth in one IC.
>
I don't know about that; NSC says that the pinout is still the same as the
16450 and 8250's.
Paul
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