> >3. What *other* uarts are out there? In microlab, we used
> > a nice DUART (same vintage as the 8250's) that was
> > buffered.
> Steve has been looking at these for a while. I believe he'd
> gotten close to the "best" serial port he could find. Steve?
The best I've seen is the Motorola MC68302, which has 3 serial ports
capable of some very good speed. However, this guy may be a little
too expensive, since its also has a 68000 CPU core in it.
Add to cost the added complexity of programming, etc. If our goal
is resonable, standard RS232 performance, which maxes out at 115.2
Kbaud, we're more than covered by the National Semi UARTS rated at
I just called the local national semi office and distributor :
1. National Semi doesn't make a four UART version of the 16550
2. Here are the stats on the 2-port version :
National Semi NS16C552V dual 16550 UART
Lots of 100 : $13.10
Sample quantities : $16.50
Package : 44 Lead Plastic Chip Carrier, about .65" X .65"