NB2DSK-SPK01 Resources - Board ID Memory

Board identification is handled courtesy of a DS2406 device (from Dallas Semiconductor). Although the device is actually a dual-addressable switch, it is used for the additional 1kbit of memory that it possesses.

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

The DS2406 is a 1-Wire® compatible device, primarily used to contain a code with which to identify the speaker board when plugged in. The NanoTalk Controller interrogates this device over a single wire, the associated signal of which is AUD_1WIRE.

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 NB2DSK-SPK01's 3.3V supply, to ensure continuous power.

Similar devices on the NB2DSK01 motherboard, all peripheral boards and 3-connector daughter boards, allow the NanoTalk Controller to detect which specific boards are available to the system.

Location on Board

The DS2406 device (designated U1) is located on the component side of the board, to the top-left of the 16-way connector (HDR1).

Schematic Reference

The 1-Wire memory device can be found on sheet 1WB_DS2406_EPROM.SchDoc (entitled 1-Wire Bus ID) of the speaker board schematics.

Further Device Information

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