It seems to take a full second or so after popwer down for VIN and Reset pins to drop below 4.2. VDD seems to do the same. Wish My measurements were a little more accurate.
Both Boards I have are doing the same thing. And the second one has been barely used. had to pull it out the Anti staic bag. I'll be able to test two more later this evening. I'd hate to really screw myself trying to replace caps.
I believe Jeff has hit this though...It sounds like power bleeding.· Does this happen with your Serial Cable disconnected (Another one I asked earlier)?·
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Chris Savage Parallax Tech Support csavage@parallax.com
Not that comments have any effect on anything, I'm just curious why this comment is here on the last line of your program, with the problems you've been describing:
HIGH 1 ' Drain CAP after power down
It almost seems that you may know about a capacitor that we may not know about?
Is there anything else hooked up to any other pin ports on the Stamp?
Just for kicks, make these the last 3 lines in your program, and let us know what happens:
DIRS $0000
STOP
END
Now, if you don't mind, run it with these 3 lines as the last lines in the program, and report the results:
·· As a note the "END" will never be executed in either scenario.· STOP does just that.· It stops executing instructions.· As for extra hardware, I wondered that myself after the pictures that were posted.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Chris Savage Parallax Tech Support csavage@parallax.com
Just trying to practice good code writing. After Jeff told me to leave LED On at the end of the CODE I just typed in that comment to keep track of where he was going to take me didn't know the road would stop there. As Far as Additional Hardware I'm using an 900 mhz RF transmitter, LCD, and additional Zilog Development Board via I2C. None of which is hooked up right now. As I posted earlier I never even noticed the problem because the code we use has an DO...LOOP in it.
The PX isn't used to say HELLO WORLD or turn A LED on and off. [noparse]:)[/noparse] I have a lot to learn but I thought its was pretty much common sense that checking to see if an LED would fade off after power down had something to do with the CAPS!
"...I just typed in that comment to keep track of where he was going to take me didn't know the road would stop there."
I'm not sure if you are asking for more help from me or not... the LED-at-the-end idea was to prove my theory that you have residual power for some time after you switch power off; the resetting problem seems to be exactly what I suggested; due to a capacitor discharging after power down. The BS2px seems to be behaving exactly as we designed it to at this point, unless I've missed something.
If you have more loads to put in the circuit as you develop it, that will help solve this power-down problem. If you don't have more loads to add and this problem is one you need to solve for the final application, perhaps a power switch that's wired to drain the remaining power through a resistor (when, and only when power is switched off) would work best.
Just for the record, END is not an executable command per se. In theory an END statement will be inserted if one is not found. However, many years ago there was a known and reported bug which probably few on this forum even remember. It was an odd compiler bug whose resolution was to add the END statement, as a circumvention. It wouldn't be the first time an old bug crept out of a compiler and reared its ugly head. Oddly, they can be very difficult bugs for the developers to troubleshoot, unless there is someone on staff who remembers it. Take it from one who's been there
There have been SO FEW actual compiler bugs, over the years, I try to remember them all - just in case. I suspect Jeff M. has something in his archival notes about it, which I only mention since he has been a part of this thread. Kudos to Parallax, Jeff, and the whole team, for so few bugs!
Thanks Jeff, I think I can work around this. The Switch is a great idea. I greatly appreciate your, Chris, and Bruce help. It was unclear what was causing the problem, and a heavy burden has been lifted. Other than this minor difficulty the PX has been great and is rock solid. I would highly recommend it not just for its horsepower but the SUPPORT you get from the PARALLAX COMMUNITY. IT sets you apart from the rest of the industry. Parallax is top of the list for OEM in the future.
Sorry, new to this whole thing, and trying to follow. Was the reason the loop hack worked that the loop was consuming power, and so draining the rest of the residual current?
Comments
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Chris Savage
Parallax Tech Support
csavage@parallax.com
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Not that comments have any effect on anything, I'm just curious why this comment is here on the last line of your program, with the problems you've been describing:
HIGH 1 ' Drain CAP after power down
It almost seems that you may know about a capacitor that we may not know about?
Is there anything else hooked up to any other pin ports on the Stamp?
Just for kicks, make these the last 3 lines in your program, and let us know what happens:
DIRS $0000
STOP
END
Now, if you don't mind, run it with these 3 lines as the last lines in the program, and report the results:
DIRS $FFFF
STOP
END
Regards,
Bruce Bates
·· As a note the "END" will never be executed in either scenario.· STOP does just that.· It stops executing instructions.· As for extra hardware, I wondered that myself after the pictures that were posted.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com
The PX isn't used to say HELLO WORLD or turn A LED on and off. [noparse]:)[/noparse] I have a lot to learn but I thought its was pretty much common sense that checking to see if an LED would fade off after power down had something to do with the CAPS!
"...I just typed in that comment to keep track of where he was going to take me didn't know the road would stop there."
I'm not sure if you are asking for more help from me or not... the LED-at-the-end idea was to prove my theory that you have residual power for some time after you switch power off; the resetting problem seems to be exactly what I suggested; due to a capacitor discharging after power down. The BS2px seems to be behaving exactly as we designed it to at this point, unless I've missed something.
If you have more loads to put in the circuit as you develop it, that will help solve this power-down problem. If you don't have more loads to add and this problem is one you need to solve for the final application, perhaps a power switch that's wired to drain the remaining power through a resistor (when, and only when power is switched off) would work best.
Thanks.
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--Jeff Martin
· Sr. Software Engineer
· Parallax, Inc.
Just for the record, END is not an executable command per se. In theory an END statement will be inserted if one is not found. However, many years ago there was a known and reported bug which probably few on this forum even remember. It was an odd compiler bug whose resolution was to add the END statement, as a circumvention. It wouldn't be the first time an old bug crept out of a compiler and reared its ugly head. Oddly, they can be very difficult bugs for the developers to troubleshoot, unless there is someone on staff who remembers it. Take it from one who's been there
There have been SO FEW actual compiler bugs, over the years, I try to remember them all - just in case. I suspect Jeff M. has something in his archival notes about it, which I only mention since he has been a part of this thread. Kudos to Parallax, Jeff, and the whole team, for so few bugs!
Regards,
Bruce Bates