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USB Power Pack II – Update

August 4, 2014

I’m still working with the USB Power Pack trying to get it to run the olduino standalone. The problem has been that the olduino/1802 stops after a few seconds.

I took the memory chip out of the 4mhz mc board and put it in the older 1.6mhz board and added the original olduino board which doesn’t have hardware spi but is capable of reading back the 1802’s memory. The memory looks ok generally and, when I loaded a blink sketch into the 1802 and put it on the power pack I was able to see that it was restarting every 10 seconds or so so the power pack must be shutting down and restarting after 10 seconds.

This is actually a bit of a relief because it eliminates a whole bunch of issues – the higher speed and so on. I have heard of people having to trick USB power packs into continuous operation by artificially drawing power. I had been hoping that my power draw of 70 ma was enough to keep it happy but I guess not.

It works fine from a wall wart so i may leave it at that but i’m going to try running the power pack over a straight usb cable – not the serial adapter to see what happens.

USB cable color codes

On a first try of just a USB cable into the power pack with no load, it showed 5V for a few seconds then went to 3.6V!

Update: Running with a simple USB cable rather than the serial adapter and a passive load, the power pack seems to cycle very briefly every 10 seconds reducing the voltage to a level that resets the AVR if not the 1802. Don’t know why but the answer is probably to try a different supply.

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