DS2423

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When issued on a multidrop bus this command will set all Overdrive-supporting devices into Overdrive

mode. To subsequently address a specific Overdrive-supporting device, a Reset Pulse at Overdrive speed

has to be issued followed by a Match ROM or Search ROM command sequence. This will speed up the

time for the search process. If more than one slave supporting Overdrive is present on the bus and the

Overdrive Skip ROM command is followed by a read command, data collision will occur on the bus as

multiple slaves transmit simultaneously (open drain pulldowns will produce a wired-AND result).

Overdrive Match ROM [69H]

The Overdrive Match ROM command, followed by a 64-bit ROM sequence transmitted at Overdrive

speed, allows the bus master to address a specific DS2423 on a multidrop bus and to simultaneously set it

in Overdrive mode. Only the DS2423 that exactly matches the 64-bit ROM sequence will respond to the

subsequent memory function command. Slaves already in Overdrive mode from a previous Overdrive

Skip or Match command will remain in Overdrive mode. All other slaves that do not match the 64-bit

ROM sequence or do not support Overdrive will return to or remain at regular speed and wait for a Reset

Pulse of minimum 480 µs duration. The Overdrive Match ROM command can be used with a single or

multiple devices on the bus.