On Thu, 27 Apr 2006 07:50:25 +0200, rtstofer <rstofer@...> wrote:

Atmel AVR Microcontroller and I have no idea what AVR stands for. I

couldn't find it on their web site either.


Richard

quote from wikipedia:

The AVRs are a family of RISC microcontrollers from Atmel. Their internal architecture was conceived by two students: Alf-Egil Bogen and Vergard Wollan, at the Norwegian Institute of Technology (NTH)[1] and further developed at Atmel Norway, a subsiduary founded by the two architects.

...

The acronym AVR has been reported to stand for Advanced Virtual RISC. It's also been rumoured to stand for the company's founders: Alf and Vegard, who are evasive when questioned about it.

endquote

ST

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I don't think anyone external to the company knows for sure.? The rumor is that it's the initials of the three people who developed it.?

Bruce


rtstofer wrote:

--- In Electronics_101@..., JanRwl@... wrote:

Duh . . . Whassa "AVR"??? Anything like "APR"???

Atmel AVR Microcontroller and I have no idea what AVR stands for. I
couldn't find it on their web site either.

Richard

It is possible
Two terminals and the other two terminals connected to
common of the bulb which could be the metal ring which
fits int o the holder. Headlight bulbs of automotives
are of this type

--- Robert Hedan <robert.hedan@...> wrote:

Yeah, but he said there was only 2 contacts at the
base of the bulb.

The only way I could imagine would be using
polarity, but that doesn't make
sense with AC.

Robert
:)

-----Message d'origine-----
De : Electronics_101@...
[mailto:Electronics_101@...] De la

part de Stefan Trethan

Envoy??? : avril 26 2006 10:09
??? : Electronics_101@...
Objet : Re: [Electronics_101] Really dumb question

of the day...

Inside are two filaments of differnt wattage.
Each contact goes to one filament, the reurn is

the base.

low wattage filament - low
high wattage filament - medium
both filaments - high.

that's what i think. Such bulbs are not sold here.

ST

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Duh . . .?? Whassa "AVR"???? Anything like "APR"???

--- In Electronics_101@..., Shawn Upton <kb1ckt@...> wrote:

Speaking of AVR's, just how different are they from
PIC'S? I've only worked with PICs so far.


Shawn Upton, KB1CKT

Like PICs, AVRs come in all sizes. For my comparison, I will talk
about the mid-range PIC - say the 16F877 (although my favorite PIC is
the 16F88) and the ATmega128 - a rather high-end chip. This is NOT a
fair comparison - it's what I have on the bench in front of me. But,
other than '128 memory size, many of the comments apply to the
ATmega16 which is available in a 40 pin DIP.

The PIC has 8k words of program storage - the '128 has 128k. The PIC
has 386 bytes of RAM, the '128 has 4k. The PIC runs at 20 MHz but
only 5M instructions/second while the '128 runs at 16 MHz and about
16M instructions/second. Further, the '128 doesn't trip over itself
with banking and paging which probably reduces the PIC's actual
execution rate to maybe 3M IPS. Oh, the '128 supports 64k of external
RAM and that could be bank switched to access a really large memory
system. I don't think you can execute out of RAM, however.

The PIC is usually programmed using a high voltage method - this is a
PITA. Low voltage programming is available on some chips. In fact
the PGM pin has been a real PITA for users unfamiliar with its'
requirements.

The '128 and many other AVRs are programmed using an SPI method at
normal voltages. This can be an advantage when you are thinking about
ICSP and how it affects your design. The '128 also supports JTAG
programming and debugging while the PIC has some kind of debugging
support but I haven't used it.

When compared to the mid-range PIC, development tools like a
full-blown C compiler are better for the '128. And they are free - I
use GNU C by way of WinAVR (although I develop on Linux at the present
time).

I use PICs and I really like the 16F88 but, given a choice, I would
use the AVRs. The only hangup I have with the '128 is building a PCB
for the small package and soldering it in place.

As I said at the beginning, this isn't a fair comparison because
Microchip has newer devices. I haven't used them because I haven't
found a FREE C development system. They offer C18 free for a while
but eventually I think you have to pay money.

I do this as a hobby and FREE is required. The only reason I play
with the Philips LPC21xx ARM chips is because that toolchain is also FREE.

I only use Xilinx FPGAs because WebPack ISE is actually FREE. The
equivalent Altera toolchain requires periodic relicensing which they
may, or may not, provide. That type of licensing does me no good. It
doesn't cost anything but there is no guarantee that they will
continue to renew it for a hobbyist.

Richard

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In a message dated 4/26/2006 8:52:48 A.M. Central Daylight Time, lcdpublishing@... writes:

Anyway, I believe inside it is 3 filements - one for each brightness,
okay, I understand that.? How does it work?<<

NO!? Just two!? One for DIMMEST; the second for BRIGHTER; and BOTH for BRIGHTEST.?

?

Speaking of AVR's, just how different are they from
PIC'S? I've only worked with PICs so far.


Shawn Upton, KB1CKT

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I like those circuits.

Installed a large contactor that way on my bench to switch everything on or off. When i get fed up with something i can punch the off button and it shuts down with a satisfying thump ;-)

ST

--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@...> wrote:

Hi guys,

I am working on version 4.0 of my CNC controller board. One of the
things I wanted to clean up was the E-Stop circuit for this.

This is how I would like it to work...

E-Stop is pressed...

Power to Motors is cut-off
Power to Spindle motor is cut-off
A logic level signal goes to all motor control chips

As I am mixing high and low voltages here, I know there are special
precautions I must take so as to not let the genie out of the bottle.

This is what I think I should have to make it all work...

The E-Stop actuator will have to contactors in it, 1 for logic and
the other for the power circuits.

1) Logic E-Stop contactor. When depressed, it takes that signal to
ground. Each of the inputs on the AVRs are pulled high with 10ks.

2) Power E-Stop contactor. Using a normally closed contactor, this
is to ground. When the butten is depressed, it is open. This
ground signal will go to the coil side of a relay(s) that switch the
power circuits on/off.

This should give me double protection (logic is off & power is off)
and it should keep the logic level voltages sepperate from the power
voltages etc.

I am sure I have something wrong as I usually do, but that's why I'm
asking :-)

Chris

There are standards. The normal Start-Stop circuit begins with a
normally closed Stop switch from one power rail to the junction of a
normally open Start switch and one side of the holding contacts. The
other side of the holding contacts connects to the other side of the
Start switch (they are in parallel, the holding contacts hold the
Start state) and this junction connects to one side of the coil. The
other side of the coil goes to common or ground. You really don't
want to switch an emergency circuit with a ground connection. Any
short circuit can simulate a ground connection.

The point is, it takes a specific action (pressing the Start button)
to get power but even the loss of power will cause the Stop function
to work. And the system won't restart.

A not particularly useful schematic is in Figure 7-16 here


Richard

Hi guys,

I am working on version 4.0 of my CNC controller board. One of the
things I wanted to clean up was the E-Stop circuit for this.

This is how I would like it to work...

E-Stop is pressed...

Power to Motors is cut-off
Power to Spindle motor is cut-off
A logic level signal goes to all motor control chips

As I am mixing high and low voltages here, I know there are special
precautions I must take so as to not let the genie out of the bottle.

This is what I think I should have to make it all work...

The E-Stop actuator will have to contactors in it, 1 for logic and
the other for the power circuits.

1) Logic E-Stop contactor. When depressed, it takes that signal to
ground. Each of the inputs on the AVRs are pulled high with 10ks.

2) Power E-Stop contactor. Using a normally closed contactor, this
is to ground. When the butten is depressed, it is open. This
ground signal will go to the coil side of a relay(s) that switch the
power circuits on/off.

This should give me double protection (logic is off & power is off)
and it should keep the logic level voltages sepperate from the power
voltages etc.

I am sure I have something wrong as I usually do, but that's why I'm
asking :-)

Chris

On Wednesday 26 April 2006 09:41 am, lcdpublishing wrote:

Last night I got to thinking about 3 way light bulbs - don't ask me
why, I donno.

Anyway, I believe inside it is 3 filements - one for each brightness,

No, only 2 filaments, that are both on for the brightest setting.

okay, I understand that. One the base of the bulb is two contacts like
a normal bulb. The switch has four positions - off, on1, on 2, and on
3. I have not looked inside a 3 switch/socket, but there can't be too
much in there as there isn't much room.

How does it work?

The lower-power is turned on first, then the medium power, and both for the
brightest setting.

I haven't had any of these around for a loooong time. I don't like them much.
And you always had one filament burn out before the other, too.

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin

You are correct (as usual). That is just the way it works. There are two contacts side-by-side in the center of the bulb socket for one end of each filament, and the threaded outer portion is the common for the other ends of the filaments (this end is the non-switched side, directly connected to the power source). The switch selects first the low wattage filament, then the high wattage filament, then both, then off.

Nels

Stefan Trethan wrote:

Stefan is correct. The two contacts on the bottom plus the shell makes the
three contacts and 4 possible combinations:
Low
Med
High = low & med
Off

Jim

Richard, good advice! You know me all to well!

Yes, I see what you are saying about the 2 10Ks. I also see what you
are saying about the inputs/outputs. I thought for sure I wouldn't
make that mistake, and have already made it - Twice. No smoke, just
problems :-(

Thanks
CHris


--- In Electronics_101@..., "rtstofer" <rstofer@...>
wrote:

--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@> wrote:

Hi Guys,

I will be needing to take one "output" from a photo interrupter
switch and connect that signal to two different AVRs as inputs.

I

am not sure if it is okay to do that or not. Here is my initial
plan....

Photo-interrupter that will pull a signal to ground.

AVR inputs both pulled high with 10K resistors.

No reason it shouldn't work EXCEPT that you now have 2 10k

resistors

in parallel so the load is 5k. SOME photo interrupters don't have

the

ability to sink much current. If you see on a scope that the

signal

doesn't come close to 0V then dump one of the resistors.

The pullup is associated with the interrupter, not the AVR pins. A
single resistor is fine.

Just be darned certain that you don't define both AVR pins as

outputs

and set them to opposite states.

You could put 330 ohm resistors in series with the input pins to
protect the chips from each other in the event they were defined as
outputs.

Richard

Yeah, but he said there was only 2 contacts at the base of the bulb.

The only way I could imagine would be using polarity, but that doesn't make
sense with AC.

Robert
:)

--- In Electronics_101@..., "lcdpublishing"
<lcdpublishing@...> wrote:

Hi Guys,

I will be needing to take one "output" from a photo interrupter
switch and connect that signal to two different AVRs as inputs. I
am not sure if it is okay to do that or not. Here is my initial
plan....

Photo-interrupter that will pull a signal to ground.

AVR inputs both pulled high with 10K resistors.

No reason it shouldn't work EXCEPT that you now have 2 10k resistors
in parallel so the load is 5k. SOME photo interrupters don't have the
ability to sink much current. If you see on a scope that the signal
doesn't come close to 0V then dump one of the resistors.

The pullup is associated with the interrupter, not the AVR pins. A
single resistor is fine.

Just be darned certain that you don't define both AVR pins as outputs
and set them to opposite states.

You could put 330 ohm resistors in series with the input pins to
protect the chips from each other in the event they were defined as
outputs.

Richard

Hi Guys,

I will be needing to take one "output" from a photo interrupter
switch and connect that signal to two different AVRs as inputs. I
am not sure if it is okay to do that or not. Here is my initial
plan....

Photo-interrupter that will pull a signal to ground.

AVR inputs both pulled high with 10K resistors.

The signal for the photointerrupter is wired to the two different
AVR chips (their inputs).

When photointerrupter is made, it pulls the signal to ground, the
AVR see this change in state at both AVRs.

For some reason, I am thinking this shouldn't work, but don't know
why. It would seem to me that the amount of current is very low and
the photo interrupter should handle switching these tiny signal to
low and high without worry.

Aside from the above concept, is there a certain type of
photointerrupter I should select (type of control it has - there are
many types).

If it helps, this photointerrupter will be used as a tachometer
input from a spindle rotating at around 18,000 RPM.

Thanks guys!

Chris

Inside are two filaments of differnt wattage.
Each contact goes to one filament, the reurn is the base.

low wattage filament - low
high wattage filament - medium
both filaments - high.

that's what i think. Such bulbs are not sold here.

ST

Last night I got to thinking about 3 way light bulbs - don't ask me
why, I donno.

Anyway, I believe inside it is 3 filements - one for each brightness,
okay, I understand that. One the base of the bulb is two contacts like
a normal bulb. The switch has four positions - off, on1, on 2, and on
3. I have not looked inside a 3 switch/socket, but there can't be too
much in there as there isn't much room.

How does it work?

Like I said, dumb question of the day :-(

Chris