You can access the EEPROM memory using the two modes:
- System Address Mode (SAM)
3968 bytes of information are available in SAM mode (but some memory areas are protected against reading and/or writing). SAM mode is recommended only for reading fields unavailable in UAM mode, for example: dongle ID. In other cases it is better to use UAM mode - User Address Mode (UAM)
In this mode memory starting with address 30 SAM is available. I. e., for example, memory item with address 33 in SAM will have address 3 in UAM and memory item with address 20 SAM is unavailable in UAM
Two modes of addressing are required so that you do not have to change your application when dongles are improved in the future and new fields will be added before address 30, since in UAM mode the addresses of memory items will remain the same. The dongle can communicate the initial address for UAM mode. This provides for both forward and backward compatibility.