EVAL-AD5933EB Datasheet, PDF (26/40 Pages) Analog Devices – 1 MSPS, 12-Bit Impedance Converter, Network Analyzer

AD5933
STATUS REGISTER (REGISTER ADDRESS 0x8F)
The status register is used to confirm that particular measure-
ment tests have been successfully completed. Each of the bits
from D7 to D0 indicates the status of a specific functionality of
the AD5933.
Bit D0 and Bit D4 to Bit D7 are treated as don’t care bits These
bits do not indicate the status of any measurement.
The status of Bit D1 indicates the status of a frequency point
impedance measurement. This bit is set when the AD5933 has
completed the current frequency point impedance measurement.
This bit indicates that there is valid real data and imaginary data
in Register Address 0x94 to Register Address 0x97. This bit is
reset on receipt of a start frequency sweep, increment frequency,
repeat frequency, or reset command. This bit is also reset on
power-up.
The status of Bit D2 indicates the status of the programmed
frequency sweep. This bit is set when all programmed incre-
ments to the number of increments register are complete. This
bit is reset on power-up and on receipt of a reset command.
Table 14. Status Register (Register Address 0x8F)
Control Word
Function
0000 0001
Valid temperature measurement
0000 0010
Valid real/imaginary data
0000 0100
Frequency sweep complete
0000 1000
Reserved
0001 0000
Reserved
0010 0000
Reserved
0100 0000
Reserved
1000 0000
Reserved
Valid Temperature Measurement
The valid temperature measurement control word is set when a
valid temperature conversion is complete indicating that valid
temperature data is available for reading at Register Address
0x92 and Register Address 0x93. It is reset when a temperature
measurement takes place as a result of a measure temperature
command having been issued to the control register (Register
Address 0x80 and Register Address 0x81) by the user.
Data Sheet
Valid Real/Imaginary Data
D1 is set when data processing for the current frequency point
is finished, indicating real/imaginary data available for reading.
D1 is reset when a start frequency sweep/increment frequency/
repeat frequency DDS start/increment/repeat command is
issued. D1 is reset to 0 when a reset command is issued to the
control register.
Frequency Sweep Complete
D2 is set when data processing for the last frequency point in the
sweep is complete. This bit is reset when a start frequency sweep
command is issued to the control register. This bit is also reset
when a reset command is issued to the control register.
TEMPERATURE DATA REGISTER
(16 BITS—REGISTER ADDRESS 0x92,
REGISTER ADDRESS 0x93)
These registers contain a digital representation of the temper-
ature of the AD5933. The values are stored in 16-bit, twos
complement format. Bit D15 and Bit D14 are don’t care bits.
Bit 13 is the sign bit. To convert this number to an actual
temperature, refer to the Temperature Conversion Formula
section.
REAL AND IMAGINARY DATA REGISTERS (16
BITS—REGISTER ADDRESS 0x94, REGISTER
ADDRESS 0x95, REGISTER ADDRESS 0x96,
REGISTER ADDRESS 0x97)
The default value upon reset is as follows: these registers are not
reset on power-up or on receipt of a reset command. Note that
the data in these registers is valid only if Bit D1 in the status
register is set, indicating that the processing at the current
frequency point is complete.
These registers contain a digital representation of the real
and imaginary components of the impedance measured for
the current frequency point. The values are stored in 16-bit,
twos complement format. To convert this number to an actual
impedance value, the magnitude—√(Real² + Imaginary²)—must
be multiplied by an admittance/code number (called a gain
factor) to give the admittance, and the result inverted to give
impedance. The gain factor varies for each ac excitation
voltage/gain combination.
Rev. E | Page 26 of 40