Data on Motorola 68705u3

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Can anyone help me out with data to get me up and running on the
68705u3 microcontroller?  I haven't been able to find much on the web
or Motorola's site.

Thanks,
-Paul

Re: Data on Motorola 68705u3
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That's one of the old (mid-1980s) HMOS parts, you're not likely to
find anything useful these days.  If you find someone with an old
Motorola Microprocessor/Microcomputer data book set (two volumes) from
that era, it will have the data sheet.  What else are you looking for?

Re: Data on Motorola 68705u3
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I've got an old coin-op game that runs on one, and I need to write my
own code for it.  My understanding is that I'll have to start from
scratch as on this chip, there's no way to read out the existing code.


...although I've read that some of them support a trick where you boot
it up off serial data loaded into RAM which can then read the ROM data
out, but I'm not sure if my device supports that.  It's a 68705U3S.

Mainly, I need:

- The schematic for the EPROM transfer programming circuit.
- An instruction set reference.
- General data about the registers and operation.

I've got a pinout, basic memory map, and assembler.

-Paul

Re: Data on Motorola 68705u3
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Hmm, Hitachi 2nd sourced the 6805 as well as doing their own variants
(6305).  That might give you a place to look for more info.  I've got an
old 8/16 bit data book, but no EPROM versions, so I can't help you with
the programming/security.

Usually they were used to scramble control inputs.  The idea was that if
you couldn't read the chip out, you couldn't duplicate the chip for
clones.  That slowed the clone makers down a day or so.  As I recall,
there was some kind of bug in the 68705 security.  I don't remember what
it was, but probably involved internal/external memory modes.  (Boot in
external mode, load "trojan" into ram, flip to internal mode?  I
guessing.)

Which game?  (Probably Taito.)

--
Ron Sharp.



Re: Data on Motorola 68705u3

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If you're still looking, I happened across a programming circuit for a
68HC705C8 in the April/May 1992 issue of Circuit Cellar.  I checked
www.circuitcellar.com had no luck with the search for an ecopy.  (Hey, it
was only 11 years ago.)

--
Ron Sharp.



Re: Data on Motorola 68705u3
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You can get scanned images on CDROM #1. See
   http://www.circuitcellar.com/products/cd.asp

-- Dave Tweed

Re: Data on Motorola 68705u3
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I figured there were probably CDROM archives, but I didn't bother looking
because (a) I didn't need the circuit (b) I had the printed copy anyway.
:^)  Oddly enough, 68HC05 circuits keep popping out at me -- I was
organizing magazines and *bam* Micro Cornucopia #49, Sept/Oct 1989 lands
in front of me.  I was looking for a simple SIMM refresh circuit, but what
the hey..

--
Ron Sharp.



Re: Data on Motorola 68705u3

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My 68hc705c8a programmer with all the source code is on my web site
at http://www.opus131.com/ijs/c8a

Ian
--

Re: Data on Motorola 68705u3
A little more research and I've found the 68HC705SR3 which appears to
be the modern equivalent of the 68705U3.  It looks like it has exactly
the same pinout and functions.  The only difference I've found so far
is that the memory map is slightly different and trades a little ROM
for a little more RAM.

Anyone know if there are any problems using this chip as a drop in
replacement?

The data sheet does have an instruction set reference, and I'm
assuming it's the same set as the 68705U3 so I've got that covered.

-Paul

Re: Data on Motorola 68705u3
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The whole set of manuals and the appnote on self-programming used to be
available from motorola not so long ago in PDF form.

Goto www.motorola.com/mcu, then find literature distribution center ->
archived documents and search for the docs you need:

M6805UM - user manual for the whole family
MC68705R3 - data sheet on P/R/U3
AN857 - appnote on self-programming


... or post another message here if you need more help.



Re: Data on Motorola 68705u3
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I've a set of the manuals which you're welcome to for the cost of
postage.
I also  have two programmers and some windowed and OTP 68705R5 devices
which we no longer use.

Re: Data on Motorola 68705u3
Thanks everyone so much for all the help!

I may have more questions later, but I've got everything I need to get
started now.  Derek Weston gave me a good deal on his data books,
Motorola 68705 development/debugger board, a bunch of 68705s, and some
other useful gear.

Also, I did find most of the info on the Motorola website from
Grzegorz' suggestion.  I had a little trouble getting there, so here's
specific instructions for future reference:

Go here:
http://www.motorola.com/semiconductors
Select - Design Support, then
Select - Documentation then scroll down to the bottom of the page, and
Select - Literature Distribution Center Archived Documents
Type the the document code (ex. M6805UM)
in the "Document Number" box and
Select - Search, the PDF files can be viewed and downloaded from here.

And again, the document names are:
M6805UM - user manual for the whole family
MC68705R3 - data sheet on P/R/U3
AN857 - appnote on self-programming circuit

-Paul

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