AD7788 Analog Devices, AD7788 Datasheet - Page 16

• Manufacturer Part Number: AD7788
• Description: 16-Bit, Single-Channel, Ultra Low Power, Sigma Delta A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7788

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7788/AD7789
Continuous Read Mode
Rather than write to the communications register each time a
conversion is complete to access the data, the AD7788/AD7789
can be placed in continuous read mode. By writing 001111XX
to the communications register, the user needs only to apply the
appropriate number of SCLK cycles to the ADC and the data-
word is automatically placed on the DOUT/ RDY line when a
conversion is complete.
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. Also, the user must ensure that the data-word is read
before the next conversion is complete.
DOUT/RDY
SCLK
DIN
CS
0x3C
Figure 13. Continuous-Read Mode
Rev. B | Page 16 of 20
DATA
If the data-word has not read the conversion before the
completion of the next conversion, or if insufficient serial clocks
are applied to the AD7788/AD7789 to read the word, the serial
output register is reset when the next conversion is complete
and the new conversion is placed in the output serial register.
To exit continuous read mode, the instruction 001110XX must
be written to the communications register while the DOUT/
RDY pin is low. While in continuous read mode, the ADC
monitors activity on the DIN line so that it can receive the
instruction to exit 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 to be written to the device.
DATA
DATA