Accessing the EEPROM

The 2K EEProm in the Datalink is accessed over a serial interface and is not directly mapped to the 6805 address space.  The entries for all of the apps are stored sequentially in the EEProm with a length/flag byte at the front of each one.  When an entry is deleted, it is done by simply setting the high bit on the flag byte.  All of the internal software simply skips over the entry.  There is no code in the watch for shuffling the data in the EEProm.

When any data is downloaded to the EEProm, it essentially clears the EEProm pointers and starts again. This has the effect of deleting all Phone, List, Anniversary, and Appointment entries if you just load a single entry down to the watch.  However, the actual data in the EEProm is never cleared out except when new data overwrites.  This means that it is possible to dump out the data in the EEProm even if the watch has been reset or only one or two entries downloaded to it.

There are some internal routines for getting to the EEProm (to be documented later) and it is possible with some work to write code that allows you to store entries in the EEProm, but you would have to figure out how to shuffle the entries in the EEProm if you wanted to add an entry without deleting everything (this isn't really as difficult as it sounds).