OpenTracker USB and Tracker3 firmware builds starting with 56294 (2 January 2013) include a 'safe mode' option to place the device temporarily into its default configuration. The safe mode entry condition is checked only when the tracker first powers on or resets.
For all tracker models, it should always be possible to recover from an invalid configuration using a cold boot procedure over the serial interface. This procedure, however, can be problematic with certain hardware setups. Safe mode offers an alternative to a serial cold boot.
Safe Mode Entry
Safe mode is entered on the OT3m by connecting the CT (counter/config) and 1W (1-Wire) pins together while the device powers up. On the OT3m, this can be accomplished by connecting CT and 1W on the front terminal block using a piece of wire. On the T3-301, a piece of wire can be inserted into pins 6 and 7 of the DB9.
The T3-Micro does not have convenient contacts for the CT and 1W inputs, but shorting pins 2 and 21 on the microcontroller will accomplish the same thing. This can be done (carefully!) using a pair of metal tweezers or a piece of wire.
To place the OpenTracker USB into safe mode, connect pins 2 (1-Wire) and 7 (GPIO1) on internal header CN4 while the device powers up.
The red LED will blink five times at startup and the indication *SAFE MODE* will appear in the command prompt banner when the tracker is in safe mode. While in safe mode, the tracker will operate from a saved copy of the default configuration, with ports A and B set to AUTO at 4800 baud. The callsign is SAFEMD. Changes to the configuration will affect the normal configuration and not the saved defaults, e.g., MYCALL W1AW will set the callsign of the regular configuration to W1AW but the effective callsign will remain SAFEMD while the device is in safe mode. To exit safe mode, use the RESET command or power off the tracker after removing the jumper used to enter safe mode.
The use of the default configuration is temporary. Normal operation will be resumed when safe mode is exited. To overwrite the active configuration with the saved defaults, use the RESET DEFAULT command. The tracker need not be in safe mode to restore defaults.