View Full Version : Propeller powers down on its own

01-18-2008, 12:34 AM
After using the propeller chip after a couple weeks, it began to power down on its own.· Initially, it would stay on for up to five minutes before powering down.· The time kept decreasing so that now it stays on for only about one second.· If I download the program to the·EEPROM, the propeller keeps rebooting itself.· The circuit consists of several LEDs.· Each LED initially had a corresponding 48ohm resister, which resulted in a calculated and measured source amperage of 22 milliamps (below the maximum 30 milliamps per pin).· At most only two LEDs would be powered simultaneously on each set of 8 pins (below the maximum 100 milliamps per set of 8 pins).· I replaced all the 48ohm resisters with 220ohm resisters, which did not fix the issue.· A new 9-volt battery did not fix the problem either.

I downloaded a different program that simply·powers only one LED.· As before, the LED stays on for about one second, then the propeller chip powers down (Yes, I remembered to include the "repeat" command·at·the end of program).· I downloaded yet another program that toggles each LED on for a fraction of a second in a chase pattern.· The propeller runs this program indefinitely without any issues.

Phil Pilgrim (PhiPi)
01-18-2008, 12:46 AM
Check your 3.3V regulator. Is it getting hot? If so, you may have a current overload somewhere, in which case the regulator will shut down when it overheats, then turn back on when it cools.


01-18-2008, 01:05 AM
Good thought, but the power LED (the one connected directly to the 3.3V regulator to ground) stays on the entire time. Only the propeller is shutting down.


Phil Pilgrim (PhiPi)
01-18-2008, 01:16 AM
Measure Vdd when the Propeller resets itself. Is it 3.3V, or something lower? The Prop has a brownout detector that resets if Vdd gets too low. Under these conditions, your power LED would continue to light.


Fred Hawkins
01-18-2008, 07:48 AM
genrev, how many cogs are you using?

01-18-2008, 07:57 AM

Post your code that shows this error.

I had a similar issue that totally stumped me for hours..
Peter Jakacki here locally looked at the code for me and fixed it...
It had something to do with stack overflow .. it was spin related..

ron mel oz..

01-18-2008, 07:18 PM
I appreciate all the feedback.· I think I·found the problem.· To my embarrassment http://forums.parallax.com/images/smilies/blush.gif, it was due to a low battery afterall.· I was unaware of the·Prop's brownout detector.· I'm just·surprise the Propeller consumed the battery so quickly.· I also find it surprising that the Propeller would run the LED chase program without any issues with a low battery, yet it would shut down if any one LED stayed on for more than·one second.··It makes me wonder if there's still another issue.· In any case, I'm up and running again for the time being.

To answer a previous question, I'm running two cogs with plans to add more.

Great products and great customer service.· Thanks!


Post Edited (genrev) : 1/18/2008 2:57:45 PM GMT

Paul Baker
01-19-2008, 12:59 AM
The current limiting resistors you originally used are rather low, the current is high enough to have the I/O's resistance in the PMOS transitor to come into play (IOW the voltage of the pin is less than 3.3V in a rather significant manner).

Something you have to consider is that 9V batteries are one of the worst types of batteries to use for powering electronics, a "monster" capacity for the battery is somewhere between 500-600 mAh. This means an ordinary 9V has capacity between 300-500 mAh, assuming median lifetime, and assuming you are always running 2 LEDs, your battery will last on the order of 4 hours. Either get a AA to 9V battery pack (a battery pack you place 6 AA batteries into and on top is the 9V terminal), or switch to using a wall-wart.

Paul Baker (mailto:pbaker@parallax.com)
Propeller Applications Engineer
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Parallax, Inc. (http://www.parallax.com)