Rainbow-electronics DS2433 Manual do Utilizador descarregar pdf (Página 13)

DS2433

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command has to occur at Overdrive Speed until a Reset Pulse of minimum 480ms duration resets all

devices on the bus to regular speed (OD = 0).

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 wire-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 DS2433 on a multidrop bus and to simultaneously set it

in Overdrive Mode. Only the DS2433 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 overdrive-capable slaves will return to

regular speed at the next Reset Pulse of minimum 480ms duration. The Overdrive Match ROM command

can be used with a single or multiple devices on the bus.

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Rainbow-electronics DS2433 Manual do Utilizador Página 13