Novena/EEPROM

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Revision as of 09:34, 27 September 2013 by Xobs (talk | contribs) (Feature bitmask)
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Novena has a utility EEPROM that can be used for storing device-specific data. This is optional, and default values will be used if it is blank / not present.

All multi-byte integers are in native host order.

Structure

EEPROM structure
Size Default Value Description Result if no EEPROM present
6 'Novena' Unterminated EEPROM signature The EEPROM contents will not be used
1 1 Version number of EEPROM structure The EEPROM contents will not be used
1 0 Reserved No change
4 0 Device serial number No change
6 (Random) Gigabit MAC address Random MAC address is generated on each boot
2 0 Feature bitmask No features are enabled

Feature bitmask

There is a bitmask field that defines various board features. In this way, a single image can be shipped that supports various components. For example, a router might not have a display, but a laptop would need to have its LCD turned on. A bit is "1" if the feature is present (and needs to be enabled), and "0" if it is not present. Note that some values are mutually-exclusive (e.g. you can only have one kind of LVDS display attached).

Feature list
Bit position Feature
1 ES8328 Audio Codec
2 Battery board
3 Retina LVDS display
4 (Reserved: Other LVDS display)