AD7416-7418 Analog Devices, AD7416-7418 Datasheet - Page 11

• Manufacturer Part Number: AD7416-7418
• Description: 10-Bit Digital Temperature Sensor (AD7416) and Single/Four-Channel ADC (AD7417/AD7418)
• Manufacturer: Analog Devices

2. Data is sent over the serial bus in sequences of nine clock
3. When all data bytes have been read or written, stop condi-
Any number of bytes of data may be transferred over the serial
bus in one operation, but it is not possible to mix read and write
in one operation, because the type of operation is determined at
the beginning and cannot subsequently be changed without
starting a new operation.
REV. B
the selected device waits for data to be read from or written
to it. If the R/W bit is a 0 then the master will write to the
slave device. If the R/W bit is a 1 the master will read from
the slave device.
pulses, eight bits of data followed by an Acknowledge Bit
from the receiver of data. Transitions on the data line must
occur during the low period of the clock signal and remain
stable during the high period, as a low-to-high transition
when the clock is high may be interpreted as a STOP signal.
tions are established. In WRITE mode, the master will pull
the data line high during the 10th clock pulse to assert a
STOP condition. In READ mode, the master device will pull
the data line high during the low period before the 9th clock
pulse. This is known as No Acknowledge. The master will
then take the data line low during the low period before the
10th clock pulse, then high during the 10th clock pulse to
assert a STOP condition.
Figure 8. Writing to the Address Pointer Register Followed by a Single Byte of Data to the Selected Data Register
Figure 7. Writing to the Address Pointer Register to Select a Data Register for a Subsequent Read Operation
SCL
SDA
START BY
MASTER
SDA
SCL
START BY
MASTER
1
1
1
1
0
0
SERIAL BUS ADDRESS BYTE
0
SERIAL BUS ADDRESS BYTE
0
1
FRAME 1
1
FRAME 1
A2
A2
SDA (CONTINUED)
SCL (CONTINUED)
A1
A1
A0
A0
R/W
R/W
ACK. BY
AD7416
ACK. BY
AD7416
9
–11–
D7
9
1
P7
WRITING TO THE AD7416/AD7417/AD7418
Depending on the register being written to, there are three dif-
ferent writes for the AD7416/AD7417/AD7418.
1. Writing to the Address Pointer Register for a subsequent
2. Writing a single byte of data to the Configuration Registers
1
D6
P7
read.
In order to read data from a particular register, the Address
Pointer Register must contain the address of that register. If
it does not, the correct address must be written to the Ad-
dress Pointer register by performing a single-byte write
operation, as shown in Figure 7. The write operation consists
of the serial bus address followed by the address pointer byte.
No data is written to any of the data registers.
or T
The Configuration Register is an 8-bit register, so only one
byte of data can be written to it. If only 8-bit temperature
comparisons are required, the temperature LSB can be ig-
nored in T
to the T
Writing a single byte of data to one of these registers consists
of the serial bus address, the data register address, written to
the Address Pointer Register, followed by the data byte,
written to the selected data register. This is illustrated in
Figure 8.
1
P6
OTI
D5
P6
ADDRESS POINTER REGISTER BYTE
P5
, T
OTI
ADDRESS POINTER REGISTER BYTE
D4
P5
HYST
OTI
and T
P4
DATA BYTE
FRAME 3
and T
D3
P4
Registers.
FRAME 2
AD7416/AD7417/AD7418
HYST
P3
FRAME 2
HYST
D2
P3
registers.
P2
, and only eight bits need be written
P2
D1
P1
D0
P1
P0
ACK. BY
AD7416
P0
ACK. BY
9
AD7416
9
ACK. BY
AD7416
STOP BY
MASTER
9
STOP BY
MASTER