Microcontroller with 7V supply and I/O tolerance ?

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Hi,

Queestion as topic :  does anyone here know of a microcontroller that
can operate with supply and I/O between 4 and 7 volts ?  If I could
have anything I wanted then a SiLabs 8051F320 would be perfect but
they can only go to 5.25V.  Alternatively almost anything in the TI
MSP430 series would do at a pinch but they also only seem to support
supply voltages up to 5.5V max.

Of course I could regulate the supply but then I would also need to
opto-isolate all the I/O which is not viable.

Many thanks,

David

Re: Microcontroller with 7V supply and I/O tolerance ?
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then old CMOS 1802 is the only one I know of. Oh, and the Motorola MC14500.

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It's not difficult, it needn't take up much room, and it makes the
system better. Why not do it? Or if that's too much, use resistive
dividers or resistors/ zeners to get the voltage down. that helps too,
you can add a cap to filter the inputs, EMC and all that.

Paul Burke

Re: Microcontroller with 7V supply and I/O tolerance ?

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Does anyone happen to have a (scanned or original paper) datasheet of
this chip? I've been looking for a veeeery long time to find it.

I remember that I owned a Motorola databook that contained it but this
has been gone during some of my moves...

-peter

--

Re: Microcontroller with 7V supply and I/O tolerance ?
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    Have you ever heard of Google?

        http://www.google.com/search?hl=en&q=MC14500&btnG=Google+Search

Norm


Re: Microcontroller with 7V supply and I/O tolerance ?

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Thanks for that very new tip -- and what does this get me? I find
quite a lot of things, but no _datasheet_

It might be that I'm not patient enough, but I've yet to see the
datesheet... Ok, I confess that I'm sometimes blind :-)

-peter
 

--

Re: Microcontroller with 7V supply and I/O tolerance ?
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I searched for "MC14500" and on the very first page of hits, the second one
is
    http://www.chipdocs.com/datasheets/datasheet-pdf/Motorola/MC14500.pdf

which, if you're registered at chipdocs, would get you a data sheet!

And there's another hit too at
    http://www.radanpro.com/el/dsl?MC14500.pdf
which AFAICT only requires registering and not a fee.

So, if you had actually used Google -- instead of just throwing up your
hands and declaring that you couldn't find it, you'd already have it.



Re: Microcontroller with 7V supply and I/O tolerance ?

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...which I actually did -- but thanks anyway.

-peter

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Re: Microcontroller with 7V supply and I/O tolerance ?
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According to the data sheet posted at Jameco for the OKI 80C85
    http://www.jameco.com/wcsstore/Jameco/Products/ProdDS/51705.pdf
it can operate with a single supply from +3 to +6 volts with an absolute
maximum of +7 volts

    Norm


Re: Microcontroller with 7V supply and I/O tolerance ?
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   osolete




Re: Microcontroller with 7V supply and I/O tolerance ?
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Keep in mind "absolute maximum of +7 volts" translates to "chip explodes at
+7.01" volts.

I'd like to know why the OP preferrs to find a possibly hard to source part
rather than use something standard with inexpensive level translation.




Re: Microcontroller with 7V supply and I/O tolerance ?
mangled snipped-for-privacy@yahoo.com (David) wrote in message
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You don't need to opto-isolate, just level-shift.  Many existing ICs can
do that.  In fact, many PC CPU runs below 2V and level-shift to 3.3V/5V.
Many microcontroller runs below 2V for much lower operating power. some
has open-collector outputs to aid lvel-shifting.

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Re: Microcontroller with 7V supply and I/O tolerance ?
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I mispoke thanks for pointing that out.  Of course any level-shifting
method would do, not just opto-isolating the I/O.  However I want it
all done on the MCU,  'cos otherwise it'll treble the board area (<
1"" square) and also treble the costs.  I'm certain this can't be an
unusual requirement - is there really no MCU currently available with
higher than 5(ish) volts tolerant I/O ?

Thanks,

David

Re: Microcontroller with 7V supply and I/O tolerance ?
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There are some, but not many.

  Highest IO spec I've seen is 100V and 300V on
VERSA HV100, HV300 see
http://www.goalasic.com/productguide.html

  Also Fairchild make uC with 12V regulators, and IIRC Microchip did
an OTP one.  SiLabs hae parts with +/-60V Analog IP pins.

  Atmel's MARC4 family is specified to 6.5V Vcc [operate]

  So higher voltage can clearly be done, but normally the CPU Core is
not designed for high voltage operation, as it is more power efficent to
regulate the core power, but maybe offer higher IO voltages.

  STm and Motorola have CMOS+Power FAB processes, that can integrate
uC + PowerMOSFETS for high volume users.

  Anything over 5.5V these days is unusual, but maybe someone will
join Goal in offering a "CPU + ULN2003" in one package ?

  -jg





Re: Microcontroller with 7V supply and I/O tolerance ?
mangled snipped-for-privacy@yahoo.com (David) wrote in message
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Maybe I don't understand what you're asking, but why not use a 3V
micro and shift it up 4V with a zener in its ground pin(s). I'm not
sure how the external I/O you need are ground referenced,
Sprow.

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Since I/O is beteen 4 and 7 volts, why do you not connect the GND of the
Micro to 4 Volts.
Most CPUs will handle that.

(Just kidding ;-)
--
Best Regards
Ulf at atmel dot com
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Re: Microcontroller with 7V supply and I/O tolerance ?
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Hi Ulf,  thanks for responding.  

I take it from your answer that Atmel don't have such a chip in their
armoury ?  I'm interested to hear from a chip mfr what the reasons
behind this might be ?  Of course I understand that CPU performance is
all optimised for certain voltages and that device densities would
suffer.  But still... a device with a higher supply and I/O voltage
tolerance must surely have many applications ?  Anything that runs of
batteries would be easier to design, for instance.  So how about
persuading the chaps back at base for us ?  :-)

Regards,

David

Re: Microcontroller with 7V supply and I/O tolerance ?

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1) Because higher voltage means higher power, and most of us need
   to minimize power.
  
2) It would require a MASSIVE investment in process design and
   test equipment.  There's no way you could ever sell enough
   to break even.

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That's putting it mildly.  NRE aside, I would think that
geometry restrictions would mean the parts would have to be a
lot more expensive than lower-voltage equivalents.

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Apparently not, or somebody would still be selling them. ;)

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Why is that?  Most cells put out 1.1-1.5V.  It would seem that
lower voltages would be a better answer than higher ones.

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I wouldn't hold my breath.

--
Grant Edwards                   grante             Yow!  Yow! Is this sexual
                                  at               intercourse yet?? Is it,
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Reply: Microcontroller with 7V supply and I/O tolerance ?
mangled snipped-for-privacy@yahoo.com (David) wrote in message
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Most Atmel fab processes top at 5.5V/6V.

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Different fab requirements for CPU and IO.

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Nop, can't even get them to provide 5V flash memories, instead of
3.3V/1.8V.  We tried and failed.

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Re: Microcontroller with 7V supply and I/O tolerance ?
mangled snipped-for-privacy@yahoo.com (David) wrote in message
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Well Dave, most chip mfr designs are a result of solving THEIR
problems, not ours (even though their "Mission Statements" would have
you believe otherwise). Or maybe they solve their top buyers (auto
mfr) problems, but thats about it (and they kick and fight the whole
way in any case).

CPU's that work under wide voltages ranges would make our life much
easier, but would cause them big headaches. Likewise for
microcontrollers with floating point, or at least a fixed point CPU
with a friggin divide instruction (i.e., where is the divide ARM?, oh
Thumb2 thanks finally).

But nooooo, they like to make nice sleek simple CPU's that solves all
their problem (the origins of the wacky RISC craze), in return, we
have to pay the price by wasting our time trying to figure out how to
optimize a binary divide algorithm (see related thread in this
newsgroup) all because they want to save some die space so they can
include a 20th serial inteface that no one needs (but is easy to
implement). Or we have to waste our time rewriting/rethinking all our
algorithms to not use a divide. Or deal with the headaches of fixed
point math and the typically non portable C code that goes along with
it(what are we still in the 1970's?).

I'm sure all the reasons why this is so is because it makes the most
sense for FORD or others who buy millions of these chips who require
the lowest recurring cost and thus is less concerned about NRE
(software development). Why if I want floating point do I have to buy
a 388 pin 1 mm ball grid array microcontroller to get it (MPC565 with
has more serial ports then I can count on two hands)? Because its best
for FORD, for embedded products which sell in the thousands or ten's
of thousands, most of chips out there don't make much sense and you
have a snowballs chance in hell changing it. Just my opinion.

Re: Microcontroller with 7V supply and I/O tolerance ?
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Unfortunately for your design, the entire semiconductor world has been
shifting to smaller dies sizes, lower power contraints,
and lower voltages. Pretty soon the 1.8v systems will be common place. That
is what is driving the market now.
As for running off of batteries, many systems run off of one Lithium-Ion
cell at 3.7v quite readily.
Many other battery powered systems use one 1.2v or two 1.2v cells and use
DC-DC converters to
generate higher voltages such as for LCD back lighting and such. Thus the
old four, six and eight cell battery designs have
all been replaced by the one or two cell battery designs.
Flash card devices all run at 3.3v or less now.
So unfortunately there is simply no market for 10v MCU's anymore. The
manufacturers aren't going to make something
that doesn't make a profit for them. It costs many millions of dollars for a
factory to tool up to make the chips.
You can't make obsolete chips if no one wants them.
Even if you wanted to buy several million 10v MCU's. none of the
manufacturers would be able to accomodate you as they
have all been switching to ever smaller die sizes and equipment and no one
has old chip manufacturing facilities left to make these kind of large die
high power chips anymore.




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