NB2DSK01 - Board ID Memory

Board identification is handled courtesy of a DS2406 device (from Maxim). The DS2406 is a 1-Wire compatible device, primarily used to contain a code with which to identify the motherboard. It is also used to contain additional information such as revision, release date, and so on. The NanoTalk Controller interrogates this device over a single wire, the associated signal of which is ONE_WIRE_NBID.

Figure 1. 1-Wire memory used to contain
the ident code for the board.

The DS2406 supports half-duplex communication at a rate of up to 16.3kbits/s. Although power for the device is sourced over the same single wire as the data itself – courtesy of a parasitic capacitor which charges when the 1-Wire bus signal line is High – the device is also fed from the NB2DSK01's 3.3V supply, to ensure continuous power.

Similar devices on all peripheral boards, 3-connector daughter boards and the Desktop Stereo Speaker Assembly NB2DSK-SPK01, allow the NanoTalk Controller to detect which specific boards are available to the system.

Location on Board

The DS2406 device (designated U19) is located on the solder side of the board, to the left of the 16-pin connector socket for the Desktop Stereo Speaker Assembly.

Schematic Reference

The 1-Wire memory device can be found on Sheet 71 (1WB_DS2406_PROTECTED.SchDoc, entitled Protected 1-Wire EEPROM) of the motherboard schematics.

Further Device Information

For more information on the DS2406 device, refer to the datasheet (DS2406.pdf) available at www.maxim-ic.com.