Avidyne IFD540 Pilot's Manual page 208

The "Download Logs" LSK is presented when "Software" is
selected on the SYS tab and the system is not in-air. When the
"Download Logs" LSK is pressed, a pair of Confirm/Cancel LSKs
are presented. Selecting Confirm will launch the Maintenance
Mode of the IFD540. From Maintenance Mode, press the right
side of the AUX page function key to select the "Logs" tab.
Ensure a USB fob is inserted in the IFD front bezel USB port and
then use a combination of the left side LSKs and the bottom right
IFD knob to select the desired combination of logs and type of
action to perform.
Datalogs Download Page (Maintenance Mode)
Pressing the "Proceed" LSK will immediately start downloading all
logs listed in the center of the page with green check marks
adjacent to them. If only a subset of the logs are to be
downloaded, use the "Un-Select All" LSK to deselect all logs and
then use the bottom right IFD knob to highlight the desired log
and push in to generate a green check mark.
The "Logs" LSK on that Maintenance Mode page provides two
options for downloading this data via dedicated LSKs. The first
option ("Full") allows a download of all data logs onto the USB
6-32 General