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2
I
C CONTROLLER
S3C2500B
2
6.4.6.4 I
C Addressing
2
The addressing procedure for the I
C is such that the first byte after the start condition determines which slave
the master will select. Usually, this first byte immediately follows the start procedure.
An exception is the "general call" address which can address all ICs simultaneously. When this address is used,
all ICs should, in theory, respond with an acknowledge. However, ICs can also be made to ignore this address.
The second byte of the general call address then defines the action to be taken.
6.4.6.5 Definition of Bits in the First Data Byte
The first seven bits of the first data byte make up the slave address. The eighth bit is the LSB, or direction bit,
which determines the direction (R/W) of the message.
When an address is sent, each IC on the bus compares the first 7 bits received following start condition with its
own address. If the addresses match, the IC considers itself addressed by the master as a slave receiver or a
slave transmitter.
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