Monthly Archives: April 2018

Custom Applications for the Digital Transceiver

To develop custom applications for the Digital Transceiver for the Raspberry Pi, the following two documents are invaluable:

  • AX5043 Datasheet – The AX5043 Datasheet (available from the ON Semiconductor web site) provides the hardware specifications and the communication interface into the AX5043 transceiver on the Digital Transceiver for the Raspberry Pi.
  • AX5043 Programming Manual – The AX5043 Programming Manual (available from the ON Semiconductor web site) provided information on the programming registers available on the AX5043 transceiver.

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.