This board is for prototyping circuits with the Texas Instruments MSP430G2xxx microcontroller. It can be used with the Texas Instruments MSP-EXP430G2 Launchpad and the newer MSP-EXP430G2ET Launchpad. It provides 3.3V/3.6V, +12V, -12V, and +5V. After you develop your project with a Launchpad you can disconnect the Launchpad, remove the MSP430G2xxx from the Launchpad, put it on the prototype board, and run it standalone.

The low voltage power supply is adjustable and can be set for voltages between 3.3V and 3.6V. This makes it compatible with both the old Launchpad (MSP-EXP430G2) which operates at 3.6V and the new one (MSP-EXP430G2ET) which operates at 3.3V. The voltage is controlled by trimpot R4.

I connected trimpot R4 as a rheostat which is good practice in a circuit like this. The most common failure of potentiometers is the failure of contact between the wiper and the element. It may become erratic (producing noise in an audio circuit like in old radios and TVs) or it may fail completely. If the wiper in R4 fails the circuit resistance will be 100 Ohms and not infinite. In addition I put R4 where it is so that if it has a wiper failure the regulator voltage will go down, not up (it goes down to slightly below 3.3V).

The ICL7660CPA is only good for 10-15mA. If you need more than that use an LT1054 and change R6 and R7 to 10 Ohms (or so). The LT1054 is good for 100mA.

Use a wire wrap socket for the MSP430G2xxx so you can wire wrap to it, and since the pins of the MSP430G2xxx are connected to the header J1 (except for the clock pins which go to the crystal) they must all be soldered. The MSP430G2xxx is laid out for a 32.768 KHz crystal. For development the J1 header pins are connected to the Launchpad. Once the project is working you can disconnect those wires and plug the programmed MSP430G2xxx into the U3 socket so the project will run standalone.

Do not connect the +3.6V on header J1 to the Launchpad. The Launchpad already has power. The reason I put it on the header is to support SPI devices like the BMP-280 temperature/pressure sensor when the proto board is running standalone.

The board supports a 16x2 LCD at header J2 with +5V and the contrast control. The data must come from the Launchpad or if you want to run the LCD when the proto board is running standalone you can put a header for the LCD on the proto board and wire the pins to the U3 pins.

One of the projects I have used it for was when I wondered what pseudo-random noise from a Linear Feedback Shift Register would sound like when it is run through a stereo faker. A stereo faker treats the mono signal as a L+R signal, then delays it and uses the delayed signal as the L-R signal. It then adds the original and delayed signals to form (L+R)+(L-R) = 2L and subtracts the original and delayed signal to form (L+R)-(L-R) = L+R-L+R = 2R. In the frequency domain this forms two comb filters with the combs alternating between the channels. This confuses the brain because it uses phase/time delay to determine the direction of a sound. When it gets fooled like this it decides that the sound must be coming from everywhere.

I programmed the MSP430G2xxx to implement two 31-bit Linear Feedback Shift Registers starting with the same initial seed. Then I clocked only the second one 1250 times. After that I clocked both together. The sequence produced by the first one was therefore always 1250 clocks behind the first one. That is how I produced the delayed pseudo-random noise signal. I recorded the results so you can hear for yourself what pseudo-random noise sounds like with stereo faker. And I am including the code for it.   

The complete documentation is at www.jmargolin.com/making/jm_pb2r2.htm .

If you are not already a Maker (and you want to be one) see my tutorial on Making Things at www.jmargolin.com/making/jm_making.htm

Now go out and do something splendid.

JM

http://www.jmargolin.com/making/jm_making.htm