HOWTO: MSP430G2 in a Standalone Environment
So it dawned on me that the TI MSP430G2 Launchpad Evaluation board isn’t very small and probably wouldn’t fit in any models smaller than G scale. I also realized that buying a bunch of the Launchpad Evaluation Boards at $10 is still cheaper than other alternatives, but not as cheap as buying the raw MSP430G2 chips by themselves (MSP430G2553 is about $2.50 for just the chip). Therefore I set out on an endeavor to figure out how to minimally power an MSP430G2 chip without the Launchpad Evaluation board.
Turns out, it’s ridiculously easy.
Minimally speaking, all you need to power a MSP430G2 off the Launchpad Evaluation board is a 10K resistor and a 1.8V to 3.6V power source. I opted to shoot for a bit more of a utility style board and used the following components:
- Dual General Purpose IC boards from Radio$hack
- 10K ohm resistor (1/8, 1/4 or 1/2 will work)
- 20 pin IC Socket
- 24x 0.100″ male headers
The Schematic (MSP430G2553 shown)
Here’s the Process
Note: Zoom in on a picture by clicking on it. Also, I apologize for the quality of the photos, the lighting was very dim and all I had available was an LED flashlight to add light.
- 1) Snap the two PCB boards apart from each other.
- 2) Put the IC Socket in the middle of one of them. Note the red lines as to how the socket should be aligned. Also, the black part of the socket should be on the side without all the copper traces. I am showing the use of a 20 pin IC socket since that is what the MSP430G2553 needs. There are other MSP430G2 chips that only require a 14 pin socket. The 14 pin variant doesn’t change the pinout nor connections for the resistor shown in stpes 5,6,7.
- 3) Flip the IC/PCB board combo over….
4) Solder the pins in place.
Pro Tip: Flux works miracles on any/all soldering jobs
- 5) On the side where you did the soldering, mark PINS 1 and 16. PIN 1 is the one on the TOP RIGHT. PIN 16 is the one on the LEFT, 5th down from the top. (For reference TOP LEFT is pin 20.)
- 6) Trim off the leads of the 10K resistor. Around 1/4 inch on each side should be about right.
- 7) Solder the 10K resistor between pins 1 and 16. It doesn’t matter which end of the resistor is connected to PIN 1 or PIN 16.
- 8) Flip the board back over so that you can see the IC socket again. Insert the short end of your headers into the board as shown. There should be 10 header pins on each side of the IC socket plus 2 more per side on the upper end of the board. (For a total of 12 per side, 24 on the entire board.)
- 9) The headers will be loose, but should roughly look like this.
- 10) Use the second IC board that came in the two pack from Radio$hack as a ‘jig’ to hold the headers in place by sandwiching the IC Socket as shown. Then flip the assembly over so the soldered resistor is showing again.
- 11) Solder the header pins to the board, much in the same fashion you did the IC socket pins. Remove the ‘jig’ and you’re done!
Note: I marked the top headers with ‘+’ and ‘-‘ symbols to help me remember which battery lead to attach where. I can pull some pretty bonehead moves and I need all the help I can get 🙂
If you’ve followed these instructions and gotten the build correct, then you now have a compact board that you can put a programmed MSP430 chip onto and use anywhere. It’s not the smallest footprint possible, but certainly smaller than the full sized Launchpad Evaluation board. You could probably take a razor saw and trim the Radio$hack board close to the Headers to lower it’s size some more.
At this point, you are free to hook up this board to any DC voltage source that can supply 1.8V to 3.6V and away you go. Here is a video of the finished board powered by a CR2032 (3Vdc) and running a simple program that rapidly alternates two LEDs. Steady state, this circuit was drawing 3.1milliamps. This could probably be lowered even farther by using a lower clock speed and making the CPU enter Low Power Mode. Anyways, here’s the video showing a MSP430G2553 deployed off the launchpad board:
Certainly, the most compact way to deploy an MSP430 would be to simply solder a 10K resistor between pins 1 and 16, directly on the chip, as well as hook up VCC to pin 1 and GND to pin 16… however, that pretty much prevents that MSP430 from ever being programmed again.
Instead, I plan on making these connections to a 20 pin IC Socket, which would enable me to remove and replace the MSP430 easily. The IC Socket should only add a few mm to the over all size… but this is for another TODO blog entry in the near future. 🙂