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three bytes of a write operation to set the internaladdress followed by subsequent read operations.To perform a selective read, the bus master sends outthe slave address with the LSB set to 0. This specifiesa write operation. According to the write protocol,the bus master then sends the address bytes that areloaded into the internal address latch. After theFM31L27x acknowledges the address, the bus masterissues a Start condition. This simultaneously abortsthe write operation and allows the read command tobe issued with the slave address LSB set to a 1. Theoperation is now a read from the current address.Read operations are illustrated below.RTC/Companion Write OperationAll RTC and Companion writes operate in a similarmanner to memory writes. The distinction is that adifferent device ID is used and only one byte addressis needed instead of two. Figure 16 illustrates a singlebyte write to this device.