Datasheet

AD7792/AD7793
Rev. B | Page 23 of 32
Continuous Read
Rather than write to the communications register each time a
conversion is complete to access the data, the AD7792/AD7793
can be configured so that the conversions are placed on the
DOUT/
RDY
line automatically. By writing 01011100 to the
communications register, the user needs only to apply the
appropriate number of SCLK cycles to the ADC, and the 16/24-
bit word is automatically placed on the DOUT/
RDY
line when a
conversion is complete. The ADC should be configured for
continuous conversion mode.
When DOUT/
RDY
goes low to indicate the end of a conver-
sion, sufficient SCLK cycles must be applied to the ADC, and
the data conversion is placed on the DOUT/
RDY
line. When
the conversion is read, DOUT/
RDY
returns high until the next
conversion is available. In this mode, the data can be read only
once. In addition, the user must ensure that the data-word is
read before the next conversion is complete. If the user has not
read the conversion before the completion of the next
conversion, or if insufficient serial clocks are applied to the
AD7792/AD7793 to read the word, the serial output register is
reset when the next conversion is completed, and the new
conversion is placed in the output serial register.
To exit the continuous read mode, the instruction 01011000
must be written to the communications register while the
DOUT/
RDY
pin is low. While in the continuous read mode, the
ADC monitors activity on the DIN line so that it can receive the
instruction to exit the continuous read mode. Additionally, a
reset occurs if 32 consecutive 1s are seen on DIN. Therefore,
DIN should be held low in continuous read mode until an
instruction is written to the device.
04855-017
DIN
SCLK
DOUT/RDY
CS
0x5C
DATA DATA DATA
Figure 19. Continuous Read