:-S arduino lilypad blues :: not in sync

Forum 2005-2010 (read only) Hardware Troubleshooting
8

Here's a little tidbit for someone more knowledgeable than me to ponder and maybe you can tell me if things are supposed to be this way:

  1. I can remove the +5V connection from the USBMini to the Lilypad and STILL HAVE POWER TO THE LILYPAD. Go figure. With the TX, RX, and Ground hooked up, I have a lit LED and it will flash when reset is pressed. If gound is unhooked at any time (even with +5V attached, there is no power)

  2. I took power readings on the USBMini (while hooked to my laptop) from TX, RX, +5V ---- with and without the jumper on and here are my readings:

TX w/out jumper = 2.42V
TX with jumper = 3.75V
RX w/out jumper = 4.80V
RX with jumper = 4.99V
+5 w/out jumper = 1.53V
+5 with jumper = 5.15V

  1. Is there supposed to be that much juice going through the TX and RX even without data flow?

  2. How is it that either the TX or RX is somehow supplying "power" to the Lilypad and allowing it to power up even WITHOUT ANYTHING hooked to the +5V connection on the Lilypad. Is there some monster Cap on there that can dispense power for at least a minute. It seems as if some of the traces on the Lilypad are crossed somewhere.

All very strange. I'm definitely a nooby, but when I disconnected the +5V and I still had power, my head almost spun off.