DS1085
SLAVE ADDRESS
A control byte is the first byte received following the START condition from the master device. The
control byte consists of a 4-bit control code; for the DS1085, this is set as 1011 binary for read and write
operations. The next three bits of the control byte are the device select bits (A2, A1, A0). The address bits
to which the DS1085 responds are factory set to 000, but can be altered by writing new values to the
ADDR register. After the new address is written, the DS1085 responds only to the new address bit values.
The master uses this to select which of eight devices are to be accessed. The set bits are in effect the three
LSBs of the slave address. The last bit of the control byte (R/W) defines the operation to be performed.
When set to a 1, a read operation is selected; when set to a 0, a write operation is selected. Following the
START condition, the DS1085 monitors the SDA bus checking the device type identifier being
transmitted. Upon receiving the 1011 code and appropriate device select bits, the slave device outputs an
acknowledge signal on the SDA line.
Figure 3. TIMING DIAGRAM
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DALLAS [ DALLAS SEMICONDUCTOR ]
