Category Archives: Blog

Hercules LaunchPad Development Kit

Working as part of the ASCENT team (kind of the R&D arm) of the volunteer Radio Amateur Satellite Corporation (AMSAT), my colleagues and I have been developing a prototype satellite controller and transceiver for future missions. While AMSAT considers much of the work to be covered by the International Traffic in Arms (ITAR) regulations, I can talk to a little bit that has been published at some point or is generic and not necessarily applicable to satellites. To avoid potential legal entanglements, we’re actually developing a ground-based transceiver for terrestrial communication at the moment.

For the controller, we’re looking at the TI Hercules SoC. I understand this is a chip is often used in safety critical applications, such as automotive controllers, because of redundancy and fault-detection built into the chip. In particular, the chip reportedly has two cores, oriented a right-angles to each other, that operate in lock-step to detect a failure of some sort. While this behavior isn’t necessarily targeted to aerospace applications, it seems it might be used in environments with a lot of RF noise, high-energy radiation, or particle radiation.

We’ve already used the LAUNCHXL2-570LC43 development kit as the processor in a UHF digital transceiver. The LaunchPad development tools include a generator that results in a framework for execution on the processor. As we’ve previously used FreeRTOS, the automatic generator of a FreeRTOS framework for the Hercules processor was particularly interesting.

Also of interest was the support for “BoosterPacks”. The pins visible on the board in the picture above expose a lot of connectivity to the Hercules processor. With reasonable effort, we developed a custom transceiver board that fits the BoosterPack pins.

Our BoosterPack uses the AX5043 transceiver and uses SPI for communication with the Hercules processor. We plan to enable a CAN bus at some point. More on the use of the AX5043 transceiver chip in that prototype in another post.

TAPR TR-Plus

The TR-Plus is a transmit/receive switch with the added capability of feeding back some of the transmitted signal back to the transmitter. This allows the transmitter to adjust the signal to compensate for distortion, something like an active noise cancelling headset. This comes as a kit and is easily assembled.

I also designed and printed a simple case to hold the TR-Plus. My SMA jacks are not perfectly aligned so the holes had to be adjusted to compensate. Thus, they aren’t quite even.

IMG_2849_cropped-563x1024

 

HPSDR LPU

The HPSDR LPU (http://www.tapr.org/kits_lpu.html)is a low noise power supply for HPSDR. It comes as a kit and is interesting because of the twenty-eight or so surface mount components. As this is my first project with any number of hand soldered surface mount components, it’s not particularly pretty, but my assembled power supply works!

 

IMG_2847_cropped-1024x744