Datasheet

BUF12840
SBOS519A –OCTOBER 2010– REVISED JULY 2011 www.ti.com
The BUF12840 acknowledges each byte. To Communication may be terminated by sending a
terminate communication, send a STOP or START premature STOP or START condition on the bus, or
condition on the bus. Only DACs that have received by not sending the acknowledge.
both bytes are updated.
To read multiple DAC registers:
Reading
1. Send a START condition on the bus.
To read the register of one DAC: 2. Send the device address and read/write bit =
LOW. The BUF12840 acknowledges this byte.
1. Send a START condition on the bus.
3. Send either the Register 0 address byte to start
2. Send the device address and read/write bit =
at the first DAC or send the address byte for
LOW. The BUF12840 acknowledges this byte.
whichever DAC is the first in the sequence of
3. Send a DAC address byte. Bits D7−D5 are
DACs to be read. The BUF12840 begins with this
unused and should be set to 0. Bits D4−D0 are
DAC and steps through subsequent DACs in
the DAC address; see Table 5. Only DAC
sequential order.
addresses 00000 to 01011 and 10000 to 11011
4. Send the device address and read/write bit =
are valid and acknowledged.
HIGH.
4. Send a START or STOP/START condition on the
5. Receive bytes of data. The first two bytes are for
bus.
the specified DAC. The first received byte is the
5. Send correct device address and read/write bit =
most significant byte (bits D15−D8, of which only
HIGH. The BUF12840 acknowledges this byte.
bits D9 and D8 have meaning). The next byte is
6. Receive two bytes of data. They are for the
the least significant byte (bits D7−D0).
specified DAC. The first received byte is the most
6. Acknowledge after receiving each byte.
significant byte (bits D15−D8, of which only bits
7. When all desired DACs have been read, send a
D9 and D8 have meaning); the next is the least
STOP or START condition on the bus.
significant byte (bits D7−D0).
7. Acknowledge after receiving each byte. See Figure 23.
8. Send a STOP condition on the bus.
Communication may be terminated by sending a
premature STOP or START condition on the bus, or
See Figure 22.
by not sending the acknowledge.
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