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From: fredm@media.mit.edu (Fred G Martin)
Subject: Re: MINI BOARD QUESTIONS, answered
Message-ID: <1992Nov24.165240.6558@news.media.mit.edu>
Sender: news@news.media.mit.edu (USENET News System)
Organization: MIT Media Laboratory
References: <1992Nov24.043853.824@mixcom.com>
Distribution: usa
Date: Tue, 24 Nov 1992 16:52:40 GMT
Lines: 53

In article <1992Nov24.043853.824@mixcom.com> jjwwjj@mixcom.com
(Technology Associates) writes: 

>1. While installing the capacitors, I noticed the parts list
>on page 40 of The Mini Board Technical Reference (Fred
>Martin, Nov. 17, 1992) lists C2 as a 1uF Tantalum. But the
>Component Side Silkscreen on page 38 shows C3 as a polarized
>(ie. Tantalum) 1uF capacitor. I assume this is a mistake in
>the parts list. I installed the 1uF Tantalum in the location
>on the silkscreen identified as C3 (right next to resistor
>R6). Is this right?

Yes, this is a mistake in the Parts Listing.  Thanks for pointing it
out.  You interpreted the intended assembly correctly.

>2. Can I apply power to test the board even though I dont
>have a CPU? I know it wont do anything, but at least I could
>test the power circuit and perhaps see the LEDs light up! Or
>will this damage something?

It won't be terribly exciting, but you won't do any damage by applying
power with the CPU missing.

>3. I do have an M68HC11EVB with an MC68HC11A1FN CPU. Could I
>take out this CPU and put it into the Mini Board? Would it
>work? Any suggestions on taking out the CPU without cracking
>it?

It would work, but the 'A1 chip has only 512 bytes of EEPROM, and it's
not mapped to the vector area of the CPU.  This means that it's not
possible to have the chip reset and jump to that memory area (without
an external memory).

You could run the downloader and download bytes into that memory.
Then you'd have to write a bootstrap program that caused the CPU to
jump to the EEPROM area.  You'd have to run this downloader each time
you wanted to reset the chip.

>4. In Fred Martins document, he talks about the best ways to
>cut female strip socket header. I scored mine with an X-acto
>knife and then broke them apart. This worked but the ends
>are pretty ugly. Perhaps I am being to much of a
>perfectionist, but has anyone else had more success with
>another technique (besides buying a mitre box and an [BX-acto
>saw blade)?

If you are patient, and you score the header *repeatedly* and on both
sides, you can get nice clean breaks.  You end up basically sawing
through the score line with your razor blade.  It's time-consuming,
but it works. 


	- Fred
