Hi! I'm Eugene and I'm new to ATMEL AVR so i dont know anything
much
about it, but I am planning to use one for my undergraduate thesis.
I would like to ask for help about the power supply requirements of
the ATMEL STK500 AVR. I'm going to use an adapter for its power
supply but i dont know what kind of adapter to use. What voltage,
amperage, and polarity of the adapter should i use?
THanks for your time!
Power Supply Requirements in ATMEL STK500 AVR
Started by ●September 1, 2003
Reply by ●September 1, 20032003-09-01
> -----Original Message-----
> From: emf_uplb [mailto:emf_uplb@emf_...]
> Sent: Monday, 1 September 2003 4:39 PM
> To: avrclub@avrc...
> Subject: [AVR club] Power Supply Requirements in ATMEL STK500 AVR > Hi! I'm Eugene and I'm new to ATMEL AVR so i dont know anything much
> about it, but I am planning to use one for my undergraduate thesis.
> I would like to ask for help about the power supply requirements of
> the ATMEL STK500 AVR. I'm going to use an adapter for its power
> supply but i dont know what kind of adapter to use. What voltage,
> amperage, and polarity of the adapter should i use?
>
> THanks for your time!
To be honest, if you can not read the instructions (which can be found
online) you will not make mach of an engineer.
From the STK 500 User Guide :
2.2 System
Requirements
The minimum hardware and software requirements are:
486 processor (Pentium is recommended)
16 MB RAM
7 MB free hard disk space
Windows 95, Windows 98, Windows NT 4.0 or higher, or Windows 2000
115200 baud RS-232 port (COM port)
10 - 15V DC power supply, 500 mA min.
The last paragraph of 2.3 states this :
An external 10 - 15V DC power supply is required. The input circuit is a
full bridge rectifier,
and the polarity of the input voltage can be selected either positive or
negative
center connector. Connect the power cable between a power supply and the
STK500.
Apply 10 - 15V DC to the power connector. The power switch turns the STK500
main
Regards,
Kat.
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Reply by ●September 1, 20032003-09-01
> From the STK 500 User Guide :
>
> 10 - 15V DC power supply, 500 mA min.
>
> The last paragraph of 2.3 states this :
> An external 10 - 15V DC power supply is required.
Actually a 9V adapter will work just as well. Not sure why they claim it has
to be 10V in the manual, when their schematics show 9V as being ok. And since
it is a linear regulator it will get a little less hot with 9V than with 12V.
As an aside, people will probably find that they already have an adapter
around they can use. For example, many common 12V adapters that come with
everything from paper shredders to computer scanners have the right sized
adapter on it. So check your power supply that came with a scanner or
something like that.
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
>
> 10 - 15V DC power supply, 500 mA min.
>
> The last paragraph of 2.3 states this :
> An external 10 - 15V DC power supply is required.
Actually a 9V adapter will work just as well. Not sure why they claim it has
to be 10V in the manual, when their schematics show 9V as being ok. And since
it is a linear regulator it will get a little less hot with 9V than with 12V.
As an aside, people will probably find that they already have an adapter
around they can use. For example, many common 12V adapters that come with
everything from paper shredders to computer scanners have the right sized
adapter on it. So check your power supply that came with a scanner or
something like that.
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
Reply by ●September 2, 20032003-09-02
Yes, this is ok for the STK board, but if you ever plan on running other
devices with the same supply beware that you will run into a problem at some
point. Why go with the bare minimum on a development board? Everything you
connect to the processor will add to the current needed. Consider the draw for
an LCD display and any other toys you want to connect. Play it safe and use a
larger supply than needed to keep from tearing your hair out at 2 am when things
do not work simply because you do not have enough power.
-Mike
----- Original Message -----
From: Patrick A. Timlin
To: avrclub@avrc...
Sent: Monday, September 01, 2003 12:14 PM
Subject: [AVR club] Re: Power Supply Requirements in ATMEL STK500 AVR > From the STK 500 User Guide :
>
> 10 - 15V DC power supply, 500 mA min.
>
> The last paragraph of 2.3 states this :
> An external 10 - 15V DC power supply is required.
Actually a 9V adapter will work just as well. Not sure why they claim it has
to be 10V in the manual, when their schematics show 9V as being ok. And since
it is a linear regulator it will get a little less hot with 9V than with 12V.
As an aside, people will probably find that they already have an adapter
around they can use. For example, many common 12V adapters that come with
everything from paper shredders to computer scanners have the right sized
adapter on it. So check your power supply that came with a scanner or
something like that.
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
To unsubscribe from this group, send an email to:
avrclub-unsubscribe@avrc...
-Mike
----- Original Message -----
From: Patrick A. Timlin
To: avrclub@avrc...
Sent: Monday, September 01, 2003 12:14 PM
Subject: [AVR club] Re: Power Supply Requirements in ATMEL STK500 AVR > From the STK 500 User Guide :
>
> 10 - 15V DC power supply, 500 mA min.
>
> The last paragraph of 2.3 states this :
> An external 10 - 15V DC power supply is required.
Actually a 9V adapter will work just as well. Not sure why they claim it has
to be 10V in the manual, when their schematics show 9V as being ok. And since
it is a linear regulator it will get a little less hot with 9V than with 12V.
As an aside, people will probably find that they already have an adapter
around they can use. For example, many common 12V adapters that come with
everything from paper shredders to computer scanners have the right sized
adapter on it. So check your power supply that came with a scanner or
something like that.
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
To unsubscribe from this group, send an email to:
avrclub-unsubscribe@avrc...
Reply by ●September 3, 20032003-09-03
> From: "Mike Putnam" <circuit@circ...>
> Yes, [a 9V supply] is ok for the STK board, but if you ever plan on
> running other devices with the same supply beware that you will run
> into a problem at some point.
Why? I didn't say anything about current, just voltage. A 9V supply will work
fine. If you hook more and more devices to your development board, then the
issue isn't the voltage, but the current you need to supply those devices, so
you can go with a 9V supply with a larger max current, say 1A vs. 500mA.
However, keep in mind that the STK500 development board is using a simply
linear regulator. Run too high a voltage or too much current, or a
combination of higher voltage and higher current and you run the risk of
overheating and blowing the regulator.
In fact I would argue if you plan on adding other devices off the development
board and still running it off the onboard linear regulator, you SHOULD use a
9V supply to minimize the wattage you have to dissipate in the regulator. Say
you run a half amp thru that regulator, a 12V supply is going to cause the
regulator to have to dissipate an additional (0.5A)(3V), 1.5 watts of power
it wouldn't have to if you used 9V instead. > Why go with the bare minimum on a development board? Everything
> you connect to the processor will add to the current needed.
Agreed and as I pointed out above, then get a larger current rated supply as
needed and realize the lower voltage input will actually benefit you in this
condition, as pointed out above. =====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
> Yes, [a 9V supply] is ok for the STK board, but if you ever plan on
> running other devices with the same supply beware that you will run
> into a problem at some point.
Why? I didn't say anything about current, just voltage. A 9V supply will work
fine. If you hook more and more devices to your development board, then the
issue isn't the voltage, but the current you need to supply those devices, so
you can go with a 9V supply with a larger max current, say 1A vs. 500mA.
However, keep in mind that the STK500 development board is using a simply
linear regulator. Run too high a voltage or too much current, or a
combination of higher voltage and higher current and you run the risk of
overheating and blowing the regulator.
In fact I would argue if you plan on adding other devices off the development
board and still running it off the onboard linear regulator, you SHOULD use a
9V supply to minimize the wattage you have to dissipate in the regulator. Say
you run a half amp thru that regulator, a 12V supply is going to cause the
regulator to have to dissipate an additional (0.5A)(3V), 1.5 watts of power
it wouldn't have to if you used 9V instead. > Why go with the bare minimum on a development board? Everything
> you connect to the processor will add to the current needed.
Agreed and as I pointed out above, then get a larger current rated supply as
needed and realize the lower voltage input will actually benefit you in this
condition, as pointed out above. =====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
Reply by ●September 3, 20032003-09-03
[snip]...
>Why? I didn't say anything about current, just voltage. A 9V supply will work
>fine. If you hook more and more devices to your development board, then the
>issue isn't the voltage, but the current you need to supply those devices, so
>you can go with a 9V supply with a larger max current, say 1A vs. 500mA.
Patrick,
I didn't say anything about your voltage spec. I was referring to current. But while you are on the subject, what about power? How can you ignore voltage in the formula?
-Mike
>Why? I didn't say anything about current, just voltage. A 9V supply will work
>fine. If you hook more and more devices to your development board, then the
>issue isn't the voltage, but the current you need to supply those devices, so
>you can go with a 9V supply with a larger max current, say 1A vs. 500mA.
Patrick,
I didn't say anything about your voltage spec. I was referring to current. But while you are on the subject, what about power? How can you ignore voltage in the formula?
-Mike
Reply by ●September 4, 20032003-09-04
> From: "Mike Putnam" <circuit@circ...>
>
> Patrick,
> I didn't say anything about your voltage spec. I was referring to current.
I don't think I ever mentioned current in my original post. I just said a 9V
supply would work. So your reply saying that might not be big enough, I
assumed you were talking about a 9V supply versus a 12V or whatever. > But while you are on the subject, what about power? How can you ignore
> voltage in the formula?
I didn't ignore voltage. I stated, at a half amp, a 12V supply would
dissipate 1.5 watts more power than a 9V supply because 0.5A(3V) [note the
second term is voltage] = an additional 1.5W of power.
Keep in mind that with a linear regulator, you have to drop the voltage
across the regulator the old fashioned way, by dissipating heat. So for a 5V
output regulator, with a 9V supply you have to drop 4V. With a 12V supply you
have to drop 7V, 3V more than the 9V supply. The voltage drop is constant. 5V
output is fixed and whatever wall wort you use, say 12V, is constant.
Therefore the power dissipated depends on how much current you pull thru the
regulator. I used the example of a half amp. At a half amp...
with a 9V supply, P = 0.5(9) = 4.5W
with a 12V supply, P = 0.5(12) = 6.0W (1.5W more)
Cool?
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
>
> Patrick,
> I didn't say anything about your voltage spec. I was referring to current.
I don't think I ever mentioned current in my original post. I just said a 9V
supply would work. So your reply saying that might not be big enough, I
assumed you were talking about a 9V supply versus a 12V or whatever. > But while you are on the subject, what about power? How can you ignore
> voltage in the formula?
I didn't ignore voltage. I stated, at a half amp, a 12V supply would
dissipate 1.5 watts more power than a 9V supply because 0.5A(3V) [note the
second term is voltage] = an additional 1.5W of power.
Keep in mind that with a linear regulator, you have to drop the voltage
across the regulator the old fashioned way, by dissipating heat. So for a 5V
output regulator, with a 9V supply you have to drop 4V. With a 12V supply you
have to drop 7V, 3V more than the 9V supply. The voltage drop is constant. 5V
output is fixed and whatever wall wort you use, say 12V, is constant.
Therefore the power dissipated depends on how much current you pull thru the
regulator. I used the example of a half amp. At a half amp...
with a 9V supply, P = 0.5(9) = 4.5W
with a 12V supply, P = 0.5(12) = 6.0W (1.5W more)
Cool?
=====
Patrick Timlin ptimlin@ptim...
http://www.geocities.com/ptimlin/
__________________________________
