AD7714 Analog Devices, AD7714 Datasheet - Page 30

• Manufacturer Part Number: AD7714
• Manufacturer: Analog Devices

Specifications of AD7714

• Resolution (bits): 24bit
• # Chan: 5
• Sample Rate: 19.2kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: (2Vref/PGA Gain) p-p,Uni (Vref)/(PGA Gain)
• Adc Architecture: Sigma-Delta
• Pkg Type: DIP,SOIC,SOP

AD7714
CONFIGURING THE AD7714
The AD7714 contains eight on-chip registers that can be
accessed via the serial interface. Communication with any of
these registers is initiated by writing to the Communications
Register first. Figure 8 outlines a flow diagram of the sequence
which is used to configure all registers after a power-up or reset.
The flowchart also shows two different read options—the first
where the DRDY pin is polled to determine when an update of
WRITE TO COMMUNICATIONS REGISTER SETTING UP
CHANNEL & SETTING UP NEXT OPERATION TO BE A
WRITE TO THE FILTER HIGH REGISTER (27 HEX)
WRITE TO COMMUNICATIONS REGISTER SETTING UP
SAME CHANNEL & SETTING UP NEXT OPERATION TO
BE A WRITE TO THE FILTER LOW REGISTER (37 HEX)
WRITE TO COMMUNICATIONS REGISTER SETTING UP
SAME CHANNEL & SETTING UP NEXT OPERATION TO
BE A WRITE TO THE MODE REGISTER (17 HEX)
WRITE TO COMMUNICATIONS REGISTER SETTING UP
SAME CHANNEL & SETTING UP NEXT OPERATION TO
BE A READ FROM THE DATA REGISTER (5F HEX)
WRITE TO MODE REGISTER SETTING UP REQUIRED
VALUES & INITIATING A CALIBRATION (20 HEX)
CONFIGURE & INITIALIZE µC/µP SERIAL PORT
WRITE TO FILTER HIGH REGISTER SETTING
UP REQUIRED VALUES (4F HEX)
WRITE TO FILTER LOW REGISTER SETTING
UP REQUIRED VALUES (A0 HEX)
POWER-ON/RESET FOR AD7714
READ FROM DATA REGISTER
NO
Figure 8. Flowchart for Setting Up and Reading from the AD7714
POLL DRDY PIN
START
DRDY
LOW?
YES
–30–
the data register has taken place, the second where the DRDY
bit of the Communications Register is interrogated to see if a
data register update has taken place. Also included in the flow-
ing diagram is a series of words which should be written to the
registers for a particular set of operating conditions. These con-
ditions are test channel (AIN6/AIN6), gain of 1, burnout cur-
rent off, no filter sync, bipolar mode, 24-bit word length, boost
off and maximum filter word (4000 decimal).
WRITE TO COMMUNICATIONS REGISTER SETTING UP
SAME CHANNEL & SETTING UP NEXT OPERATION TO BE A
READ FROM THE COMMUNICATIONS REGISTER (0F HEX)
WRITE TO COMMUNICATIONS REGISTER SETTING UP
SAME CHANNEL & SETTING UP NEXT OPERATION TO
BE A READ FROM THE DATA REGISTER (5F HEX)
POLL DRDY BIT OF COMMUNICATIONS REGISTER
READ FROM COMMUNICATIONS REGISTER
READ FROM DATA REGISTER
NO
DRDY
LOW?
YES
REV. C