Between about
1983 and about 1990, I wrote a fair amount of software
for a communications board which I designed, and which used an 8088,
an 8259, an 8253, 8255s, and, for some reason I cannot remember
now, I
think it used 6850s for the serial ports. We started out with all
Motorola peripheral chips but found out that the timer chip wouldn't
work properly together with the Intel bus, so we switched to Intel. I
do have the distinct impression that we kept the 6850s for some
reason, probably price, and, I think, simplicity. We had no need for
synchronous communications so that would have been a reason.
One of the more common chips used for async (as well as sync) back
then was the Signetics 2651 (and 2661). A 28 pin package, simple to
interface, with a built-in baud rate generator. The successful
orphan of the 2650 CPU family.
Another popular chip used was the Intel 8274 dual-channel chip,
basically a clone of the Z80 SIO chip.
There were many other comm chips by the major makers, but these two
packed a lot of bang-for-the-buck.
Z8530. 'Nuff said.
Well, not quite 'nuff...it's an AMAZINGLY nice chip! I've done
quite a bit with it (both in my designs and in existing systems) and
have always been impressed with its capabilities.
-Dave
--
Dave McGuire
Port Charlotte, FL