MSP430 running without power!

Well, not quite :D

I had plugged the Launchpad into USB for convenience but didn't have need for it yet, the code that was on the MSP430G2231 in the socket didn't do much besides blink the LEDs on P1.0 and P1.6

This was slightly annoying but instead of removing the USB cable (which tends to run away and hide) I decided to remove the VCC jumper from J3. My thinking was…

"This will cut power to the device and cease that annoying blinking!"

Turns out I was wrong! Have a look at the video :D

 

With the VCC jumper the LEDs blink bright, taking the VCC jumper off they still blink but not quite as bright.

Not shown in the video disconnecting the TXD or RXD line will reduce the brightness further, removing both will not allow the LEDs to light.

The above doesn't always seem to be true suggesting we are right on the limit of what the MSP430 can run on sourcing power through random pins.

In the code all pins are left at their default state except for P1.0 and P1.6 which are set to outputs.

Any ideas?