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.