IC Substitution: 16550 for 16450?

[clh333]

I have an old Everex IO board which has provision for a second serial port, provided you add a 1488, a 1489 and a 16450 (or 8250, say the notes). Jameco et alii have 16550s but not 16540s, so far as I can tell. I have read that the 16550 is simply a better version of the 16450, pin compatible and that it runs all of the same software.

I have the '48 and '49 but need to acquire the 16450. If anyone has an opinion to the contrary or has any caveats about substitution please let me know.

Thanks,
-CH-

 

[Eudimorphodon]

To my knowledge it should be fine, when a 16550 is initially powered up its FIFO defaults to behaving like the 16450, so any BIOS software that expects the older UART won't know the difference.

 

[Chuck(G)]

Yes, it'll function; you can even replace an 8250 with a 16550. The question of whether or not your software will detect it and take advantage of the added FIFO is another matter. Be sure that you get a 16550A or later, however. The early 16550s had a bug where the FIFO could not be enabled, so they were little better than the 16450s they replaced.

 

[clh333]

All I need to know, thanks.
-CH-