Stellaris LM4F120 LaunchPad Thoughts

I just received my Stellaris LaunchPad in the mail! It shipped on the 25th and arrived at my house today on the 27th. I put in the order within a few minutes of getting TI’s email announcing the pre-order. Looking at TI’s store they are now estimating 2-8 weeks for orders placed before prior to the 25th. I remember it taking them a while to get the MSP430 launchpad shipped when that was first announced, and I would say the LM4F120 is a much better deal for $5. It just goes to show the LaunchPad’s are being shipping.

The demo application on the board shows off the basic hardware on the board. The RGB LED is fades between different colors when left alone and the buttons cycle between the different colors. Holding both buttons down enters hibernation mode.

Not shown in the video the demo application also features serial control over the color, light intensity, and hibernation. The serial drivers do need to be installed for this to work, although I had no issues getting everything up and running on Windows 7 per TI’s included instructions.

Running the demo application draws around 22mA, switching to hibernation reduces this to an average of 850µA. In both cases the LEDs draw the most current. I figured because they included the hibernation feature I might as well test it.

The biggest draw to getting the Stellaris LaunchPad was that it is a Cortex-M4 ARM core which is very capable when it comes to doing DSP. That coupled with the dual on-chip 1MSPS Analog to Digital Converter means that some very interesting mixed signal projects should be possible with this dev board. An interesting feature of the LM4F120’s ADCs are that they can be phase shifted relative to each other (around 20-30°), and they can also be shifted by 180° to get an effective 2MSPS sampling rate. Considering most entry-level MCU’s have ADCs with a 200kSPS or lower sample rate this is fantastic.

Unlike the MSP430 LaunchPad the programmer cannot be separated from the without cutting through and destroying the programming section. The headers are also pre-soldered instead of being included in the box.

An interesting thing to note is that the programmer is exactly the same LM4F120 microcontroller which handles all of the USB serial communications and debugging interface.

I do wish that the board had a more interesting peripheral than an RGB LED, but for 5$ I can’t complain. The LM4F120 MCU has plenty of on-chip features and I am excited to see what people come up with using this development board.


TI’s TMP006

Today I received a sample order from Texas Instruments. Among several ICs for a school project I also sampled some of the TMP006  “Infrared Thermopile Sensors”. I don’t have a PCB to solder them to yet, so I decided to take some macro photos.

I apologize for the quality. The top light in my microscope burned out and so all the pictures are light from the side with a handheld flashlight while trying to hold my camera steady and focused through the eyepiece. After this buying a nice microscope with a built in digital camera seems like a good idea.

The title picture is the top of the chip. It has the part number (TMP006), the alignment mark in the lower left, and what is probably the lot trace code. The interesting part is when the chip is flipped over. This is a chip-scale BGA package, which is convenient in terms of the amount of space it takes up, but almost impossible to solder by hand. To give a sense of scale the spacing between the center of each metal ball is 0.5mm.

I would have liked to get some higher quality pictures, but that will have to wait until I have a better setup .