AD7710ANZ Analog Devices Inc, AD7710ANZ Datasheet - Page 24

• Manufacturer Part Number: AD7710ANZ
• Description: IC ADC SIGNAL CONDITIONING 24DIP
• Manufacturer: Analog Devices Inc

Specifications of AD7710ANZ

• Data Interface: Serial
• Number Of Bits: 24
• Sampling Rate (per Second): 1.03k
• Number Of Converters: 1
• Power Dissipation (max): 45mW
• Voltage Supply Source: Analog and Digital, Dual ±
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 24-DIP (0.300", 7.62mm)
• Resolution (bits): 24bit
• Sampling Rate: 1.02kSPS
• Input Channel Type: Single Ended
• Supply Voltage Range - Digital: 4.75V To 5.25V
• Supply Current: 4.5mA
• Digital Ic Case Style: DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7710
SIMPLIFYING THE EXTERNAL CLOCKING MODE
INTERFACE
In many applications, the user may not need to write to the on-chip
calibration registers. In this case, the serial interface to the AD7710
in external clocking mode can be simplified by connecting the TFS
line to the A0 input of the AD7710 (see Figure 14). This means
that any write to the device will load data to the control register
(because A0 is low while TFS is low), and any read to the de-
vice will access data from the output data register or from the
calibration registers (because A0 is high while RFS is low). Note
that in this arrangement the user does not have the capability of
reading from the control register.
Another method of simplifying the interface is to generate the
TFS signal from an inverted RFS signal. However, generating
the signals the opposite way around (RFS from an inverted
TFS) will cause writing errors.
MICROCOMPUTER/MICROPROCESSOR INTERFACING
The AD7710’s flexible serial interface allows for easy interface
to most microcomputers and microprocessors. Figure 15 shows
a flowchart for a typical programming sequence for reading data
from the AD7710 to a microcomputer, while Figure 16 shows a
flowchart for writing data to the AD7710. Figures 17, 18, and
19 show some typical interface circuits.
Figure 15 shows continuous read operations from the AD7710
output register, where the DRDY line is continuously polled.
Depending on the microprocessor configuration, the DRDY line
may come to an interrupt input, in which case the DRDY will
automatically generate an interrupt without being polled. Read-
ing the serial buffer could be anything from one read operation
up to three read operations (where 24 bits of data are read into
an 8-bit serial register). A read operation to the control/calibra-
tion registers is similar, but, in this case, the status of DRDY
can be ignored. The A0 line is brought low when the RFS line
is brought low during a read register.
The flowchart also shows the bits being reversed after they have
been read in from the serial port. This depends on whether the
microprocessor expects the MSB of the word first or the LSB of
the word first. The AD7710 outputs the MSB first.
Figure 16 shows a single 24-bit write operation to the AD7710
control or calibration registers. This shows data being trans-
ferred from data memory to the accumulator before being writ-
ten to the serial buffer. Some microprocessor systems allow data
to be written directly to the serial buffer from data memory.
Writing data to the serial buffer from the accumulator generally
consists of either two or three write operations, depending on
the size of the serial buffer.
Figure 14. Simplified Interface with TFS Connected to A0
INTERFACE
LINES
FOUR
SDATA
RFS
SCLK
TFS
A0
AD7710
–24–
Figure 16 also shows the option of the bits being reversed before
being written to the serial buffer. This depends on whether the
first bit transmitted by the microprocessor is the MSB or the
LSB. The AD7710 expects the MSB as the first bit in the data
stream. In cases where the data is being read or being written in
bytes and the data has to be reversed, the bits have to be reversed
for every byte.
Figure 15. Flowchart for Continuous Read Operations
to the AD7710
CONFIGURE AND
INITIALIZE C/ P
SERIAL BUFFER
ORDER OF BITS
RFS, TFS HIGH
SERIAL PORT
POLL DRDY
RFS HIGH
REVERSE
RFS LOW
START
BRING
BRING
BRING
READ
DRDY
LOW?
YES
NO
3
REV. G