LTC3206 Datasheet, PDF (8/16 Pages) Linear Technology – I2C Multidisplay LED Controller

LTC3206
U
OPERATIO
Byte Format
Each byte sent to the LTC3206 must be 8 bits long followed
by an extra clock cycle for the Acknowledge bit to be
returned by the LTC3206. The data should be sent to the
LTC3206 most significant bit (MSB) first.
Acknowledge
The Acknowledge bit is used for handshaking between the
master and the slave. An Acknowledge (active LOW)
generated by the slave (LTC3206) lets the master know
that the latest byte of information was received. The
Acknowledge related clock pulse is generated by the
master. The master releases the SDA line (HIGH) during
the Acknowledge clock cycle. The slave-receiver must pull
down the SDA line during the Acknowledge clock pulse so
that it remains a stable LOW during the HIGH period of this
clock pulse.
Slave Address
The LTC3206 responds to only one 7-bit address which
has been factory programmed to 0011011. The eighth bit
of the address byte (R/W) must be 0 for the LTC3206 to
recognize the address since it is a write only device. This
is equivalent to an 8-bit address where the least significant
bit of the address is always 0. If the correct seven bit
address is given but the R/W bit is 1, the LTC3206 will not
respond.
Bus Write Operation
The master initiates communication with the LTC3206
with a START condition and a 7-bit address followed by the
Write Bit R/W = 0. If the address matches that of the
LTC3206, the LTC3206 returns an Acknowledge. The
master should then deliver the most significant data byte.
Again the LTC3206 acknowledges and the cycle is re-
peated two more times for a total of one address byte and
three data bytes. Each data byte is transferred to an
internal holding latch upon the return of an Acknowledge.
After all three data bytes have been transferred to the
LTC3206, the master may terminate the communication
with a STOP condition. Alternatively, a REPEAT-START
condition can be initiated by the master and another chip
on the I²C bus can be addressed. This cycle can continue
indefinitely and the LTC3206 will remember the last input
of valid data that it received. Once all chips on the bus have
been addressed and sent valid data, a STOP condition can
be sent and the LTC3206 will update its command latch
with the data that it had received.
In certain circumstances, the data on the I²C bus may
become corrupted. In these cases the LTC3206 responds
appropriately by preserving only the last set of complete
data that it has received. For example, assume the LTC3206
has been successfully addressed and is receiving data
when a STOP condition mistakenly occurs. The LTC3206
will ignore this stop condition and will not respond until a
new START condition, correct address, new set of data
and STOP condition are transmitted.
Likewise, if the LTC3206 was previously addressed and
sent valid data but not updated with a STOP, it will respond
to any STOP that appears on the bus independent of the
number of REPEAT-STARTs that have occurred. An ex-
ception occurs if a REPEAT-START is given and the
LTC3206 successfully acknowledges its addressed. In
this case, it will not respond to a STOP after the first data
byte is acknowledged. It will, however, respond after the
third data byte is acknowledged.
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