Subject: Re: MIPS R3000 - 2nd update

From: [email-masked] (Neil Russell)
Date: Wed, 23 Jun 93 15:15:00 PDT

> Neil, what happens with the boot PROM interface: can it be set
> to feed the CPU with either byte order?

Duno.  I'll check.  I'd be surprised if the 3730 didn't just take
care of it.

> >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.

> All the S3 chips that I managed to find out about are SMT. They _don't_
> plan to make PGA versions. Again, Steve's got some opinions about VGA
> chips, and I think he's right. I think we'd do well to stay away from
> complicated stuff like these things, and just shoot for a straight
> framebuffer.

If the required video bandwidth is going to his the main bus hard
(which I think t will) we will need something extra to run the
VRAM.  There are plenty of chips that can do this, but they are
mostly too expensive, or are SMT.  The only exception that comes
to mind is the TMS 34010, which can be has for us$20 in small quantities
and does come in J-lead.  This issue really needs some serious
investigation.

-- 
Neil Russell		(The wizard from OZ)
Pyramid Technology			Email:  [email-masked]
3860 N. First Street			Voice:  (408) 428-7302
San Jose, CA 95134-1702			  FAX:  (408) 428-8845

---

From: Drew Eckhardt <[email-masked]>
Date: Wed, 23 Jun 1993 16:46:03 -0600

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 
1.5M baud. 

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

Pricing :

Lots of 100 : $13.10
Sample quantities : $16.50

Package :  44 Lead Plastic Chip Carrier, about .65" X .65"

---

From: [email-masked] (Neil Russell)
Date: Wed, 23 Jun 93 18:06:33 PDT

> Package :  44 Lead Plastic Chip Carrier, about .65" X .65"

Sounds like we have our serial chip...