Re: questions (about x21)

[Soeren Tiedemann <tiedema@xxxxxxxxxxxxxxxxxxxx>]

Hi Greg!

> I'm pretty new to electronics engineering, but I've been following MISC
> stuff for a while...what I want to do is make a protable x21 (probably P21
> since it is easily obtainable in convenient DIP packaging) box.  By portable
> I mean that it has to fit in my pocket.  I want to use it to log body
> sensors (ultimately I want to take an EEG), respond to a simple input
> device (two metal bars, one at +5V, one at -5V, on my left arm...on my
> right hand a glove with metal tips going to appropriate
> diodes/buffers/etc), and uotput through what will probably end up being
> one of those simple serial 40x4 text LCDs. 

Sounds good. You will of course have much more possibilities with P21!

> I'm a big fan of FORTH 

... there we are, that's our common basis, isn't it? ;-)

> (though an inexperienced FORTH programmer...

Maybe that will have been the past, soon!

I'm too tied to Unix/C for professional work),

:-(

> So my question is: can I reasonably wirewrap up a board with the
> P21?  I don't know much about the relevant issues, but I get the
> impression that going above 10MHz with wirewrap is just begging for
> trouble. 

Jeff has his F21d wire wrap testboard running at a few hundred MHz!!! ( Of
course professional work ;-)

 I don't need much RAM and I want to keep everything as simple
> (and low power...I'm contemplating powering it off of my own movements,
> so no DRAM for me...I might even forego EPROM and have it only bootable
> when connected to one of my other computers to download the bootcode)
> as possible, so I don't think any of the existing boards will do what I'm
> looking for.  I don't care much about performance, so on any other chip
> (like the PTSC1000), I'd just run the clock lower, but I get the
> impression that the P21 doesn't have a clock per se.

No, lower the power and it will slow down. Raise power and it is running
faster. P21 boots at about 4.75V and can be pushed to 7V if other
components will go along. ( They won't, so 5.5V is recommended maximum. )

I don't think that P21 will have troubles to talk to 60-70ns FPM-DRAM
chips. The integrated memory cprocessor is designed for that.

> 	Also, I want more concrete details on the P21.  I suspect C.H.
> Ting's MuP21 Programming Manual has what I'm looking for.  While I don't
> mind paying for the thing, I would like to have something to read before I
> order everything.  I'm a college student and $50 is still enough money that
> I'd like to at least do some research before shelling out the cash.  I'm
> looking for instruction set summary, pinout, maybe current draw info,
> etc., just so I can get a feel for the chip.

Of course, the ultimate web-site for you is Jeff's
   www.ultratechnology.com.

Jeff decided to offer the S21-simulator for free. Also he provides the
boot-ROM's with tons of P21-stuff ( math's, graphics, I/O ) for free!!
It is the P21-forth 1.02 and the newer P21-forth 1.04. They are designed
for different boards.

Dr. Ting provides best service, talk to him! The MuP21-manual covers a lot
of stuff and covers different versions of chips and testboards. It maybe
very confusing when studying the manual on its own.

If you are really going to explore P21 in order to get a feeling for these
chips ( I started that way, too ) feel free to contact me. I can send
you a lot of stuff to start with. 

I'm still so excited about these Forth-engines. I have much fun and learn
a lot and I have real hardware meanwhile. So I can test nearly everything
on these chips and it convinced me even more, that Chuck's design
methods are outstanding. I love these little toys a lot! ;-)

I deeply admire Chucks's obsession in getting the most out of a
small piece of silicon and Jeff's and Dr. Tings research and engineering
efforts to bring up MISC-computers. Thanks to them.  

Best wishes,

Soeren