Thanks, Clark. I am very fortunate to post the
following info from Chipdir-L:
Quote
"..
It depends on the characters behind 'MC68HC05', the
so-called postfix, could you write them down.
Among us we have a lot of Motorola-expertise and
databooks etc. Please also tell us the production date
on the chip, something like 9534 perhaps? Or give an
indication how old the computer is. Most chips in a
printed circuit board have a code like 9534, the first
two digits are the year (95) and the last two digits
are the week number (34). Just look at the dates of
about five to ten chips and you'll know what date the
printed circuit board was produced after. (And usually
shortly after, because keeping unused stock costs
money).
Here are more tips about chip 'spotting':
http://www.chipdir.info/spotting.htm
>So I hope it is flashable;
No version of the 6805 had Flash, that would be the 08
family, many years later.
I wish they would do a 68HC11 in flash, I find the 11
and the 68000 are the easiest chips to program in
assembler, than all of the others I've done.
In those days memory like this wasn't flash yet I
think, but EEPROM. It might help to make the
distinction when you are doing more research.
If it is not a 68705xxx then it is a ROM part.
When it's a systematical problem it's probably the
10-year EEPROM issue.
I'd go more with static damage myself.
As a shot in the dark cover the 6805 with black
electrical tape and try that. They where very light
sensitive. Mostly an issue when programming the
EPROM based parts.
End Quote
--- Clark Martin <[EMAIL PROTECTED]> wrote:
> At 8:15 PM -0700 5/6/04, George Mogiljansky wrote:
> >The final word on the 68HC05:
> >Quote:
> >"..they were one-time-programmable. Some had
> quartz
> >windows versions that could be erased with a UV
> light.
> > The MC68HC908 series are code compatible with the
> '05
> >and are FLASH.."
> >From Roger Shaefer, owner of website dedicated to
> this
> >chip.
>
> 68HC05 - Mask programmed ROM version
>
> 68HC705 - EPROM, UV erasable
>
> 68HC805 - EEPROM, electrically erasable.
>
> There's a version of the 68HC705 that doesn't have
> the quartz lid.
> It's known as One-Time-Programmable (OTP).
>
> The Mask programmable are the cheapest but minimum
> order is usually
> 10,000 parts.
>
> The next cheapest is the OTP version of the 68HC705.
> These are used
> for small production runs.
> Years ago I bought a cheap programmer that Motorola
> sold (for $68.05). It's real fun to debug as you
basically have to incorporate any debugging functions
into your target code. Like making it beep (if there
is a beeper) when you reach a certain point in the
code.
>
> p.s. I think the windows are just glass now. Either
> the changes in the light spectrum used or
improvements in glass brought it on. The reason for
using quartz originally was that it passed the UV
light
> much better than glass.
> --
> Clark Martin
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