riscy
[Top] [All Lists]

Re: misc stuff

To: riscy@pyramid.com
Subject: Re: misc stuff
From: caret@pyramid.com (Neil Russell)
Date: Thu, 8 Jul 93 0:40:51 PDT
In-reply-to: <m0oDoTA-00039LC@zarniwoop.chi.il.us>; from "Andrew Dyer" at Jul 7, 93 10:24 pm
Reply-to: riscy@pyramid.com
Sender: riscy-request@pyramid.com
> - we should reserve an input or two for "manufacturing" jumpers
>   so that s/w can run some internal diagnostics and board test stuff

I was planning to see what was left of the I/O pins on the 3730 for
just the reason.  Maybe if we run out, we need a spare PAL to implement
these plus some LEDs.

> - save a few bits to read the SIMM ID bits, so that s/w can know
>   what size DRAM is installed in each bank and 'do the right thing'

You don't need that.  Its possible to figure it out in S/W.

> - a name for the %^*%(* thing, how about 'Foghorn' (after Foghorn
>   Leghorn of course)  If that is too Americentric, feel free to suggest
>   something else.  Waldorf Salad? LOAM (Linux on a MIPS)?

Good plan, but don't quit your day job.

> - for serial/parallel ports on board, how about a 16C552 - two 
>   16550 uarts and a IBM compatible centronics parallel port with 8 bit
>   cpu interface.  Made by TI and others.  Also don't forget those
>   pesky line interface chips.

I still think that parallel should go on the ISA bus.  I know its cheap,
but this thing is getting too expensive.  As for RS-232 drivers,
Motorola 145406, has 3 transmitters and 3 receivers.  You need one
per port.

> - does someone have a heat chamber to test this thing at elevated 
>   temperature for a while? It may be GPL h/w, but it doesn't have to
>   be flaky...

My kitchen at about 3pm gets to about 110F!!  :-)  (The sun gets
it just the wrong way.)

> - think about cooling options for the CPU.  The 33MHz 79R3051E in the MJ
>   package runs pretty hot - I'm sure the 40MHz 3081E will really cook,
>   especially with more cache on chip.  I would plan on a heat sink and/or fan.
>   Don't burn your hands :-)

My NCD-19r (with has a LSI r3k) runs warm at 33MHz; cooler than my 486.
There are temperature specs in the 3081 data sheets.  We just need to
check it, as you say.

> - for debug, put some headers around the CPU for each pin.  If you only 
>   run the local bus to the 3730 it will be hard to hook a logic analyzer to
>   either the 3730 or the 3081 without using expensive test clips.

The logic analysers that I have access to come with those clips.  In any
case, Waldorf want a socket next to the CPU, so this would do.

> - we should budget for appropriate filters and such for EMI.  If waldorf
>   wants to sell this commercially it will have to pass VDE and/or FCC
>   (or CISPR) and/or other agency approvals.  Does Waldorf have a 
>   site where they can scan the unit? Or are they going to do their own
>   layout and only test their version?

Hell, I forgot about FCC.  Isn't that a requirement before any sales in
the US?  I've only done designs for the Australian market which doesn't
need FCC (or anything).  Has someone gone though this before?

-- 
Neil Russell            (The wizard from OZ)
Pyramid Technology                      Email:  caret@pyramid.com
3860 N. First Street                    Voice:  (408) 428-7302
San Jose, CA 95134-1702                   FAX:  (408) 428-8845

 

<Prev in Thread] Current Thread [Next in Thread>