Datasheet
AD7730/AD7730L
–12–
Table V. Summary of On-Chip Registers
Power-On/Reset
Register Name Type Size Default Value Function
Communications Write Only 8 Bits Not Applicable All operations to other registers are initiated through
Register the Communications Register. This controls whether
subsequent operations are read or write operations
and also selects the register for that subsequent
operation. Most subsequent operations return con-
trol to the Communications Register except for the
continuous read mode of operation.
Status Register Read Only 8 Bits CX Hex Provides status information on conversions, calibra-
tions, settling to step inputs, standby operation and
the validity of the reference voltage.
Data Register Read Only 16 Bits or 24 Bits 000000 Hex Provides the most up-to-date conversion result from
the part. Register length can be programmed to be
16 bits or 24 bits.
Mode Register Read/Write 16 Bits 01B0 Hex Controls functions such as mode of operation, uni-
polar/bipolar operation, controlling the function of
AIN2(+)/D1 and AIN2(-)/D0, burnout current,
Data Register word length and disabling of MCLK
OUT. It also contains the reference selection bit, the
range selection bits and the channel selection bits.
Filter Register Read/Write 24 Bits 200010 Hex Controls the amount of averaging in the first stage
filter, selects the fast step and skip modes and con-
trols the ac excitation and chopping modes on the
part.
DAC Register Read/Write 8 Bits 20 Hex Provides control of the amount of correction per-
formed by the Offset/TARE DAC.
Offset Register Read/Write 24 Bits 800000 Hex Contains a 24-bit word which is the offset calibration
coefficient for the part. The contents of this register
are used to provide offset correction on the output
from the digital filter. There are three Offset Regis-
ters on the part and these are associated with the
input channels as outlined in Table XIII.
Gain Register Read/Write 24 Bits 59AEE7 Hex Contains a 24-bit word which is the gain calibration
coefficient for the part. The contents of this register
are used to provide gain correction on the output
from the digital filter. There are three Gain Registers
on the part and these are associated with the input
channels as outlined in Table XIII.
Test Register Read/Write 24 Bits 000000 Hex Controls the test modes of the part which are used
when testing the part. The user is advised not to
change the contents of this register.
WEN ZERO RW1 RW0 ZERO RS2 RS1 RS0
RDY STDY STBY NOREF MS3 MS2 MS1 MS0
MD2 MD1 MD0 B/U DEN D1 D0 WL
HIREF ZERO RN1 RN0 CLKDIS BO CH1 CH0
SF11 SF10 SF9 SF8 SF7 SF6 SF5 SF4
SF3 SF2 SF1 SF0 ZERO ZERO SKIP FAST
ZERO ZERO AC CHP DL3 DL2 DL1 DL0
ZERO ZERO DAC5 DAC4 DAC3 DAC2 DAC1 DAC0
REV. B