Datasheet
AD7416/AD7417/AD7418
Rev. I | Page 16 of 24
Reading Data From the AD7416/AD7417/AD7418
Reading data from the AD7416/AD7417/AD7418 is a single-
byte or 2-byte operation. Reading back the contents of the
configuration register is a single-byte read operation, as shown
in Figure 18, with the register address previously having been
set by a single-byte write operation to the address pointer
register.
Reading data from the temperature value register, the T
OTI
setpoint or T
HYST
setpoint register is a 2-byte operation, as
shown in Figure 19. It is also possible to read the most
significant bit of a 9-bit or 10-bit register in this manner.
Note that when reading back from the AD7416/AD7417/
AD7418, no more than three bytes of data must be read back.
A stop command must be inserted at the end of the read
communication. If a stop command is not inserted by the
master and the AD7416/AD7417/AD7418 receive more SCL
cycles than the maximum needed for three bytes of data, then
the I
2
C interface on the AD7416/AD7417/AD7418 pulls the
SDA line low and prevents it from going high again. To recover
the AD7416/AD7417/AD7418 interface, the part must be
powered off and on again. Reference the AN-686 Application
Note, Implementing an I
2
C® Reset at www.analog.com for more
information on I
2
C interfaces.
SCL
1 19 9
S
DA 1 0 0 1
START BY
MASTER
ACK. BY
AD741x
1
NO ACK. BY
MASTER
STOP
BY
MASTER
FRAME 2
SINGLE DATA BYTE FROM AD741x
1
FRAME 1
SERIAL BUS ADDRESS BYTE
A1 D7 D6 D5 D4 D3 D2 D1 D0A0A2 R/W
01126-017
1
AD741x = AD7416/AD7417/AD7418.
Figure 18. Reading a Single Byte of Data from the Configuration Register
SCL
1 1
1
9
9
9
S
DA 1001
START BY
MASTER
ACK. BY
AD741x
1
ACK. BY
MASTER
NO ACK. BY
MASTER
STOP
BY
MASTER
FRAME 2
MOST SIGNIFICANT BYTE FROM AD741x
1
FRAME 3
LEAST SIGNIFICANT DATA BYTE FROM AD741x
1
FRAME 1
SERIAL BUS ADDRESS BYTE
SCL (CONTINUED)
SDA (CONTINUED)
A2 A1 D15 D14 D13 D12 D11 D10 D9 D8
D6D7 D5 D4 D3 D2 D1 D0
A0 R/W
01126-018
1
AD741x = AD7416/AD7417/AD7418.
Figure 19. Reading Two Bytes of Data from the T
OTI
Setpoint or T
HYST
Setpoint Register