AD7796 Analog Devices, AD7796 Datasheet - Page 19

• Manufacturer Part Number: AD7796
• Description: Low Power 16-Bit Sigma-Delta A/D Converter for Bridge Sensors
• Manufacturer: Analog Devices

Specifications of AD7796

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: ± (Vref/128)
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

Continuous Read Mode
Rather than write to the communication register each time a
conversion is complete to access the data, the AD7796/AD7797
can be configured to automatically place the conversions on the
DOUT/ RDY line. By writing 01011100 to the communication
register, the user need only apply the appropriate number of
SCLK cycles to the ADC. 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 conversion,
sufficient SCLK cycles must be applied to the ADC. The data
conversion is placed on the DOUT/ RDY line. When the conver-
sion is read, DOUT/ RDY returns high until the next conversion
is available. In this mode, the data can be read only once.
DOUT/RDY
SCLK
DIN
CS
0x5C
Figure 16. Continuous Read
Rev. A | Page 19 of 24
DATA
The user must also 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 AD7796/AD7797 to
read the word, the serial output register is reset when the next
conversion is complete. The new conversion is placed in the
output serial register.
To exit continuous read mode, the instruction 01011000 must
be written to the communication register while the DOUT/ RDY
pin is low. While in continuous read mode, the ADC monitors
activity on the DIN line to 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.
DATA
AD7796/AD7797
DATA