Allow flash programming over UART

Problem environment

Connected to a host computer, the sendcomm transceiver would benefit from firmware upgrades over a Raspberry Pi 40-pin connector such as UART or SPI.

Expected result

The firmware can be upgraded directly from the connected host, by programming its flash storage.

Actual result

The firmware can only be upgraded by programming over JTAG or SWD.

Severity level

This is low priority because project requirements do not state a particular programming interface.

According to the transceiver manufacturer:

Currently, the only way to update firmware is using SWD interface. However we have an ASF reference example available in ASF v3.48 “MLS Sample Application” for LoRaWAN Firmware Update Over The Air (FUOTA/FOTA). Please refer to the ASF extension in Atmel Studio or download Standalone ASF release. Find the quick start guide attached. Document is available in the standalone ASF v3.48 release. Once you download the package, please extract the zip folder andrefer to folder “asf-standalone-archive-3.48.0.98\xdk-asf-3.48.0\thirdparty\wireless\lorawan\apps\fuota_demo”.