Datasheet
AD7992
Rev. 0 | Page 22 of 28
WRITING TWO BYTES OF DATA TO A LIMIT
REGISTER OR HYSTERESIS REGISTER
Each of the limit registers and hysteresis registers are 12-bit
registers, so two bytes of data are required to write a value to
any one of them. Writing two bytes of data to one of these
registers consists of the serial bus write address, the chosen
limit register address written to the address pointer register,
followed by two data bytes written to the selected data register.
See Figure 27.
If the master is write-addressing the AD7992, it can write to
more than one register with out re-addressing the ADC. After
the first write operation has completed for the first data register,
during the next byte, the master writes to the address pointer
byte to select the next data register for a write operation. This
eliminates the need to re-address the device in order to write to
another data register.
SDA
ACK. BY
AD7992
ACK. BY
AD7992
119 9
C4 C3 C2 P2 P1 P0
R/W
A0A1A2A300
SCL
1
C1
P3
199
D7 D6 D5 D2 D1/0 D0/0
D4
D3
ACK. BY
AD7992
STOP BY
MASTER
LEAST SIGNIFICANT DATA BYTEMOST SIGNIFICANT DATA BYTE
SCL (CONTINUED)
S
DA (CONTINUED)
FRAME 1
SERIAL BUS ADDRESS BYTE
START BY
MASTER
FRAME 2
ADDRESS POINTER REGISTER
91
0
00
D10 D9 D8
0
D11
ACK. BY
AD7992
03263-0-008
Figure 27. Two-Byte Write Sequence
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