I am attempting to create an SPI communication to an ancillary circuit through an intermediary board and the nRF52840 USB dongle. If I start with the zephyr sample spi_flash and the nrf52840dk I can run and see the log files over the com port and USB. Now, if I have attached a nor flash to an intermediary board driven be the nRF52840 USB dongle, is there a best practices way to create the port. Unable to track the documentation to do this very common firmware development technique, find a similar application and port it to the needed application, within the nrf SDK Zephyr amalgamation. It seems I can open v2.9.0 SDK from within the nrfconnect desktop into VSCode, copy an existing application out of the Zephyr/samples directory creating a stand alone application, pick the nrf52840dongle_52840 board, and add an overlay.
Question: where are the syntax rules for an overlay for the nrf52840dongle_nrf52840? Would this be the only necessary edit to creating a nrf52840 USB dongle communicating qspi to a nor flash?
Cy Drollinger