AD7730LBR Analog Devices Inc, AD7730LBR Datasheet - Page 37

• Manufacturer Part Number: AD7730LBR
• Description: A/D Converter (A-D) IC
• Manufacturer: Analog Devices Inc

Specifications of AD7730LBR

• Peak Reflow Compatible (260 C): No
• No. Of Bits: 24 Bit
• Leaded Process Compatible: No
• Features: Bridge Transducer, Compl. Anal. Front-End
• Package / Case: 24-SOIC
• Rohs Status: RoHS non-compliant
• Number Of Bits: 24
• Sampling Rate (per Second): 600
• Data Interface: DSP, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 125mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: EVAL-AD7730LEBZ - BOARD EVALUATION FOR AD7730EVAL-AD7730EBZ - BOARD EVAL FOR AD7730
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

CONFIGURING THE AD7730
The AD7730 contains twelve on-chip registers that can be accessed via the serial interface. Figure 5 and Figure 6 have outlined a
flowchart for the reading and writing of these registers. Table XIX and Table XX outline sample pseudo-code for some commonly
used routines. The required operating conditions will dictate the values loaded to the Mode, Filter and DAC Registers. The values
given here are for example purposes only.
Write 03 Hex to Serial Port
Write 800010 Hex to Serial Port
Write 04 Hex to Serial Port
Write 23 Hex to Serial Port
Write 02 Hex to Serial Port
Write B180 Hex to Serial Port
Wait for RDY Low
Write 02 Hex to Serial Port
Write 9180 Hex to Serial Port
Wait for RDY Low
1
Write 02 Hex to Serial Port
Write 2180 Hex to Serial Port
Write 21 Hex to Serial Port
Set DIN Line of AD7730 Low
READ_DATA: Wait for RDY Low
Read 24-Bit Data From Serial Port
Loop to READ_DATA Until All Data Gathered
Write 30 Hex to Serial Port
REV. A
This operation is not necessary if the default values of the Filter Register or the DAC Register are the values used in the application.
Table XX. Pseudo-Code for Setting Up AD7730 for Continuous Conversion and Continuous Read Operation
Table XIX. Pseudo-Code for Initiating a Self-Calibration after Power-On/Reset
1
1
1
1
/* Writes to Communications Register Setting Next Operation as Write to
Filter Register*/
/* Writes to Filter Register Setting a 50 Hz Output Rate in CHOP Mode*/
/* Writes to Communications Register Setting Next Operation as Write to
DAC Register*/
/* Writes to DAC Register Setting a Subtraction Value of 7.5 mV (5 V Refer-
ence) on the TARE DAC*/
Mode Register*/
/* Writes to Mode Register Initiating Internal Full-Scale Calibration for 0 mV
to +10 mV Input Range*/
/* Wait for RDY pin to go low to indicate end of calibration cycle*/
Mode Register*/
0 mV to +10 mV Input Range*/
/* Wait for RDY pin to go low to indicate end of calibration cycle*/
/* The part has now completed self-calibration and is in idle mode*/
Mode Register*/
/* Writes to Mode Register Starting Continuous Conversions for 0 mV to
+10 mV Input Range*/
Read From Data Register*/
/* Ensures Part is not Reset While in Continuous Read Mode*/
/* Wait for RDY pin to go low to Indicate Output Update*/
/* Read Conversion Result from AD7730's Data Register*/
/* Ends Continuous Read Operation and Places Part in Mode Where It
Expects Write to Communications Register*/
/* Writes to Communications Register Setting Next Operation as Write to
/* Writes to Communications Register Setting Next Operation as Write to
/* Writes to Mode Register Initiating Internal Zero-Scale Calibration for
/* Writes to Communications Register Setting Next Operation as Write to
/* Writes to Communications Register Setting Next Operation as Continuous
–37–
AD7730/AD7730L