DS92LX1621 Datasheet, PDF (29/44 Pages) National Semiconductor (TI) – 10 - 50 MHz Channel Link III Serializer and Deserializer with Embedded Bi-Directional Control Channel

FIGURE 22. Read Byte
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FIGURE 23. Basic Operation
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FIGURE 24. START and STOP Conditions
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SLAVE CLOCK STRETCHING
In order to communicate and synchronize with remote de-
vices on the I²C bus through the bi-directional control channel,
slave clock stretching must be supported by the I²C master
controller/MCU. The chipset utilizes bus clock stretching
(holding the SCL line low) during data transmission; where
the I²C slave pulls the SCL line low prior to the 9th clock of
every I²C data transfer (before the ACK signal). The slave
device will not control the clock and only stretches it until the
remote peripheral has responded; which is typically in the or-
der of 12 μs (typical).
CAD PIN ADDRESS DECODER
The CAD pin is used to decode and set the physical slave
address of the Serializer/Deserializer (I²C only) to allow up to
six devices on the bus using only a single pin. The pin sets
one of six possible addresses for each Serializer/Deserializer
device. The pin must be pulled to VDD (1.8V, NOT VDDIO))
with a 10 kΩ resistor and a pull down resistor (RID) of the
recommended value to set the physical device address. The
recommended maximum resistor tolerance is 0.1% worst
case (0.2% total tolerance).
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