Electrical – msp430 launchpad PWR led blinking

launchpadmsp430vcc

I want to use MSP430 launchpad to control a switch working between 1.65V and 2.75V.
So, I wanted to force Vcc value to 2V instead of 3,3V while it is connected to my PC. I connected Vcc and GND pins to a power supply delivering 2V. But, now, I have a real problem. Even after taking off connection cables, Power led blinks and Vcc varies between 0V and 3,3V. I think that my kit doesn't work anymore. Could you tell me if it is the case.

Fortunately, I have another kit, I decided to work with it. But I don't know to force my Vcc to 2V to control my switch while the launchpad is connected to my PC.

Thank you very much !
Alice

Best Answer

Since you connected the 2V supply directly to VCC while the board is powered, the regulator on board is delivering 3.3V to the VCC through the USB as well. This means that you are connecting a lower potential supply (2V) directly to a higher potential one (3.3V) and depending on the current sink capability of the 2V supply it may appear like a short to the regulator, very likely frying it in the process.

Try testing the old MSP430 chip with the new board, if it works then that means your old board is fried.

To power the board with 2V, DO NOT connect the launchpad to USB or any other supply. If you must need to connect the launchpad to your PC, then you should look into "voltage translation" circuits that translates 3.3V signals from your MSP430 to the supply voltage of the switch.