Wanting to use my TI Launchpad as more than just a development board I thought I’d do a few experiments using it as an in-system programmer. After a few tripping points I was able to get it working and then some. It seems that the device is not limited to just the value line of microcontrollers it was intended to support. In the image above I’m using it to program an MSP430F2272 which is a pretty powerful little chip with 32 KB of program space. Click through the break for more information on the setup.
I started by etching a breakout board for the 38TSSOP package so that I had something usable. Drag soldering to the rescue, this turned out to be easier than I had expected.
Once I had access to the pins it was just a matter of checking out the connections used on the Launchpad board and hooking up the f2272. It turns out you only need three; TEST, RST, and GND. You can power the circuit externally or make a fourth connection to the voltage. I was sad to see that the jumper header doesn’t have GND on it so in addition to using an IDC cable, you can see in the image at the top that there’s an orange jumper wire going to the ground-pin breakout from the chip socket.
But I didn’t quite have it working yet. I had problems reliably connecting to and talking to the chip. After studying the schematic (ZIP) I realized I was being plagued by a floating reset pin. I grabbed a 4.7k resistor as a pull-up to volatge and communications are now perfect. For my test code I’m building a small version of pong using a Nokia 3595 LCD screen.
I’m using 100% open source tools for this which means I’m not limited to a 2k code output. You can setup these tools for yourself by following our TI Launchpad on Linux tutorial.