AD7416/AD7417/AD7418
the Address Pointer Register, followed by the data byte writ-
ten to the selected data register. This is illustrated in Figure 9.
3. Writing two bytes of data to the T
OTI
or T
HYST
Register.
If 9-bit resolution is required for the temperature setpoints,
two bytes of data must be written to the T
OTI
and T
HYST
registers. This consists of the serial bus address, the register
address written to the address pointer register, followed by
two data bytes written to the selected data register. This is
illustrated in Figure 10.
READING DATA FROM THE AD7416/AD7417/AD7418
Reading data from the AD7416/AD7417/AD7418 is a one or
two byte operation. Reading back the contents of the Configura-
tion Register is a single byte read operation, as shown in Figure
11, the register address previously having been set by a single-
byte write operation to the Address Pointer Register.
Reading data from the temperature value, T
OTI
or T
HYST
Regis-
ter, is a two-byte operation, as shown in Figure 12. It is also
possible to read the most significant bit of a 9-bit/10-bit register
in this manner.
1
9
1
SCL
9
SDA
START BY
MASTER
1
0
0
1
A2
A1
A0
R/W
ACK. BY
AD7416
P7
P6
P5
P4
P3
P2
P1
P0
ACK. BY
AD7416
FRAME 1
SERIAL BUS ADDRESS BYTE
1
SCL
(CONTINUED)
9
1
FRAME 2
ADDRESS POINTER REGISTER BYTE
9
SDA
(CONTINUED)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
ACK. BY
AD7416
STOP BY
MASTER
ACK. BY STOP BY
AD7416 MASTER
FRAME 3
MOST SIGNIFICANT DATA BYTE
FRAME 4
LEAST SIGNIFICANT DATA BYTE
Figure 10. Writing to the Address Pointer Register Followed by Two Bytes of Data to the T
OTI
or T
HYST
Register
1
SCL
9
1
9
SDA
START BY
MASTER
1
0
0
1
A2
A1
A0
R/W
ACK. BY
AD7416
D7
D6
D5
D4
D3
D2
D1
D0
NO ACK. BY
MASTER
STOP BY
MASTER
FRAME 1
SERIAL BUS ADDRESS BYTE
FRAME 2
SINGLE DATA BYTE FROM AD7416
Figure 11. Reading a Single Byte of Data from the Configuration Register
1
SCL
9
1
9
SDA
START BY
MASTER
1
0
0
1
A2
A1
A0
R/W
ACK. BY
AD7416
D15
D14
D13
D12
D11
D10
D9
D8
ACK. BY
MASTER
FRAME 1
SERIAL BUS ADDRESS BYTE
1
SCL (CONTINUED)
FRAME 2
MOST SIGNIFICANT DATA BYTE FROM AD7416
9
SDA (CONTINUED)
D7
D6
D5
D4
D3
D2
D1
D0
NO ACK. BY STOP BY
MASTER
MASTER
FRAME 3
LEAST SIGNIFICANT DATA BYTE FROM AD7416
Figure 12. Reading Two Bytes of Data from the T
OTI
or T
HYST
Register
REV. G
–13–
AD [ ANALOG DEVICES ]
