From: clau@acs.ucalgary.ca (Christopher Lau)
Subject: Re: Upgrading a ZyXEL 1496E to an E+
Date: Mon, 11 Jan 93 21:45:20 GMT
Organization: The University of Calgary, Alberta, Canada

mckeeveb@monashee.sfu.ca (Gumby - The unknown user) writes:
> mju@mudos.ann-arbor.mi.us (Marc Unangst) writes:
> 
> >Then I stand corrected.  I'm now sorry that I didn't get a chance to
> >take a look at the E+ we had in a week ago; we'll probably never sell
> >one (too much extra cost for too little extra features), and it would
> >have been nice to compare them.
> 
> The latest round of boards are basically E+ machines with a few minor
> changes:
> 
> 1) a 12 MHz CPU rather than 16MHz running at 20..
> 2) Custom labelled DSP chips with internal RAM to avoid the daughter board.
> 

I've got one of the E's ZyXEL was shipping at the time of the last COMDEX
show.   Its got the 12 MHz cpu, but it has the 1992 piggyback card.


> >For reference: I have a ZyXEL U-1496E, s/n S2B0230110, mainboard s/n
> >2A00227492.  The mainboard appears to be rev. B1.  The piggyback DSP
> >RAM board is the 1992 model, rev. 1.  There is a jumper wire soldered
> >between the far two pins on jumper J3, and no jumper wire on J4.
> 
> That's the larger RAM board...
> 
> >Now, are you telling me that simply by putting in a new DSP RAM board,
> >changing that jumper wire, and loading E+ EPROMs, I could have an E+?
> >If this is true, then the upgrade would definitely be worthwhile.  If,
> >on the other hand, we're still talking about replacing the 68000 with
> >a faster model or other complex modifications, I'll stand by my
> >position that an E->E+ upgrade is not practical.
> 
> There may also be a checksum/serial number/model number programmed into
> the EEPROM where the profiles are stored. (this is a 512 byte EEPROM of
> which there are 4 profiles of 56 bytes each and some phone numbers and
> passwords... lots of spare room)
> 
> >>On all the units made after the E+ was released, there is a jumper on the
> >>main board to select processor speed.  There really is no difference.
> 
> >I'm assuming that this is the soldered jumper under the DSP RAM board
> >and behind the DTR LED, not some other jumper that's using a jumper
> >block.
> 
> Actually, I think the speed is handled by two jumpers (each of which
> has 'CK' in their labelling)
> 
> >Interestingly enough, there are also a few empty solder pads to the
> >left of the 68000 chip.  There are two marked JP2, two marked C97, two
> >marked L3, and a 14-pin DIP marked U41.  To the right of the 68000
> >there is another empty capacitor, C87.  Does anyone know if these
> >board positions are used in the E+?
> 
> Not sure... I'll get back to you on that.

All interesting stuff..   but none of you was listening carefully enough:
The point I was trying to make was that even if a hardware upgrade ISN'T
POSSIBLE (with/without great effort), since the DSPs are the things doing
most of the work, can't some of the E+ features be implemented on an E??
(I'm under the impression that even though the 68k parts are not running
the same speed in E and E+ models, the TMS32025 DSPs ARE?)  In this case,
as long as the 68000 doesn't have to do much, we could probably even force
an E to do 19200 (although I don't think it will have the horsepower to 
go up to 76800 with compression- I might be wrong, since an E is supposed to
be able to go up to 57600 with compression when running in 16.8 mode).
By the same reasoning, we SHOULD be able to put CELP on an E model as well.
I don't need the thing to do v.fast (although it would be nice), but some
of the so-called "advanced" features would be useful.

> 
> -- 
>     Rob McKeever  VE7ICJ  rmckeeve@sfu.ca  mckeeveb@sfu.ca  604-291-0457
> "Do you know what standards are?  They're career paths for people who don't
>  want to work!" - John Parkinson, Ernst & Young at the BCDMA Conference '92
>        -*-          Standard Disclaimers should be adequate        -*-

c4
-- 
Christopher Lau                      |    Dammit Jim, I'm a doctor,
The University of Calgary            |    not an engineer!
Dept. of Electrical & Computer Engg. |    Well, you're an engineer now..
lau@enel.ucalgary.ca -OR- clau@acs.ucalgary.ca -OR- root@fusion.cuc.ab.ca