CMOS to TTL
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Is there a logic level translator or something else to go from CMOS
to TTL?
Thanks,
Frank
to TTL?
Thanks,
Frank
Comments
There are several "flavors" of CMOS, and with some you don't need to do any
translating for use with TTL signal levels. I'm not sure, though, if you're
talking about translating signal levels/voltages, or replacing CMOS
components with TTL components. I'll guess that it's the former...
If you can get your hands on a copy of "The Art of Electronics, 2nd ed."
there is a nice chart on p. 475 with the input and output signal levels for
a number of popular digital IC families. The 74HCTxxx family perfectly
matches TTL signal levels. It, along with TTL, Stamps and Microchip PICs,
has the input high/low voltage threshold at roughly 1.5 volts. The fact
that the CMOS outputs are much closer to 0 volts for a low and 5 volts for a
high adds noise immunity vs. the TTL output voltage levels. So the
74HCTxxx, Stamp, and PIC CMOS output signal voltages will drive TTL inputs
nicely.
...Or were you talking about the older 4xxx CMOS parts that may be operating
at voltages other than 5 volts? There are ways to deal with that as well.
Randy
www.glitchbuster.com
> Is there a logic level translator or something else to go from CMOS
> to TTL?
>
> Thanks,
> Frank
>
>
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I may just try and see if it will work without any extra chips.
I have a tool that operates at 3V. It has a computer port that
outputs CMOS levels. I purchased a cable that did CMOS -> RS232.
Thought I would eliminate the cable.
Thanks,
Frank
--- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
wrote:
> Hi Frank,
>
> There are several "flavors" of CMOS, and with some you don't need
to do any
> translating for use with TTL signal levels. I'm not sure, though,
if you're
> talking about translating signal levels/voltages, or replacing CMOS
> components with TTL components. I'll guess that it's the former...
>
> If you can get your hands on a copy of "The Art of Electronics, 2nd
ed."
> there is a nice chart on p. 475 with the input and output signal
levels for
> a number of popular digital IC families. The 74HCTxxx family
perfectly
> matches TTL signal levels. It, along with TTL, Stamps and
Microchip PICs,
> has the input high/low voltage threshold at roughly 1.5 volts. The
fact
> that the CMOS outputs are much closer to 0 volts for a low and 5
volts for a
> high adds noise immunity vs. the TTL output voltage levels. So the
> 74HCTxxx, Stamp, and PIC CMOS output signal voltages will drive TTL
inputs
> nicely.
>
> ...Or were you talking about the older 4xxx CMOS parts that may be
operating
> at voltages other than 5 volts? There are ways to deal with that
as well.
>
> Randy
> www.glitchbuster.com
>
>
>
>
> > Is there a logic level translator or something else to go from
CMOS
> > to TTL?
> >
> > Thanks,
> > Frank
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> >
> >
> > Yahoo! Groups Links
> >
> > To visit your group on the web, go to:
> > http://groups.yahoo.com/group/basicstamps/
> >
> > To unsubscribe from this group, send an email to:
> > basicstamps-unsubscribe@yahoogroups.com
> >
> > Your use of Yahoo! Groups is subject to:
> > http://docs.yahoo.com/info/terms/
> >
> >
volt serial to +/-12 volt converter. I used it between a cell phone
and a PC. It works just like a regular serial 232 level converter.
Remember the 4 caps.
If you connect your 3 volt gadget via the Max 3232cpe, in to BS port
16, you are online. Or bye a regular Max232 to convert down from
12volt to TTL 5 volt, and use Input 0-15 on the stamp. But then you
end up with two serial converters. (Not the best solution regarding
noise and stability)
I recommend you to study the serial converters for future use. They
are wary handy when you need to develop something to BS. Hook up a
few LED to get an understanding of data flow. Remember 1K resistor
to LED on the 12V side.
If you are planning to convert regular 3 volt Logic signal, try
Motorola HC244A or HC245A.
STEIN.
--- In basicstamps@yahoogroups.com, "franksmith512"
<franksmith512@y...> wrote:
> Thanks Randy!
>
> I may just try and see if it will work without any extra chips.
>
> I have a tool that operates at 3V. It has a computer port that
> outputs CMOS levels. I purchased a cable that did CMOS -> RS232.
> Thought I would eliminate the cable.
>
> Thanks,
> Frank
>
>
>
> --- In basicstamps@yahoogroups.com, "Randy Jones"
<randyjones@w...>
> wrote:
> > Hi Frank,
> >
> > There are several "flavors" of CMOS, and with some you don't
need
> to do any
> > translating for use with TTL signal levels. I'm not sure,
though,
> if you're
> > talking about translating signal levels/voltages, or replacing
CMOS
> > components with TTL components. I'll guess that it's the
former...
> >
> > If you can get your hands on a copy of "The Art of Electronics,
2nd
> ed."
> > there is a nice chart on p. 475 with the input and output signal
> levels for
> > a number of popular digital IC families. The 74HCTxxx family
> perfectly
> > matches TTL signal levels. It, along with TTL, Stamps and
> Microchip PICs,
> > has the input high/low voltage threshold at roughly 1.5 volts.
The
> fact
> > that the CMOS outputs are much closer to 0 volts for a low and 5
> volts for a
> > high adds noise immunity vs. the TTL output voltage levels. So
the
> > 74HCTxxx, Stamp, and PIC CMOS output signal voltages will drive
TTL
> inputs
> > nicely.
> >
> > ...Or were you talking about the older 4xxx CMOS parts that may
be
> operating
> > at voltages other than 5 volts? There are ways to deal with
that
> as well.
> >
> > Randy
> > www.glitchbuster.com
> >
> >
> >
> >
> > > Is there a logic level translator or something else to go from
> CMOS
> > > to TTL?
> > >
> > > Thanks,
> > > Frank
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Yahoo! Groups Links
> > >
> > > To visit your group on the web, go to:
> > > http://groups.yahoo.com/group/basicstamps/
> > >
> > > To unsubscribe from this group, send an email to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > >
> > > Your use of Yahoo! Groups is subject to:
> > > http://docs.yahoo.com/info/terms/
> > >
> > >
These are pin compatible with the MAX232 and fit in our RS-I boards:
http://www.al-williams.com/rs1.htm -- very handy for breadboarding.
Regards,
Al Williams
AWC
Will try the HC244A. That should do it. Even the Max3232cpe through
a Max232A is better than a $70 cable. I plan to have two or three of
my gadgets running at a time.
Happy Holidays,
Frank
--- In basicstamps@yahoogroups.com,
just logic 0-3 volt converting to 0-5 volt (or vise versa). So stick
to serial converter if it's serial, and logic converter like the
HC244/245 when it's logic converting.
Stein
--- In basicstamps@yahoogroups.com, "franksmith512"
<franksmith512@y...> wrote:
> Stein,
>
> Will try the HC244A. That should do it. Even the Max3232cpe
through
> a Max232A is better than a $70 cable. I plan to have two or three
of
> my gadgets running at a time.
>
> Happy Holidays,
> Frank
>
>
>
> --- In basicstamps@yahoogroups.com,