AD7761_17 Datasheet, PDF (60/76 Pages) Analog Devices – 8-Channel, 16-Bit, Simultaneous Sampling ADC with Power Scaling, 110.8 kHz BW

Data Sheet
FUNCTIONALITY
GPIO FUNCTIONALITY
The AD7761 has additional GPIO functionality when operated
in SPI control mode. This fully configurable mode allows the
device to operate five GPIOs. The GPIOx pins can be set as inputs
or outputs (read or write) on a per pin basis.
In write mode, these GPIO pins can be used to control other
circuits such as switches, multiplexers, and buffers, over the
same SPI interface as the AD7761. Sharing the SPI interface in
this way allows the user to use a lower overall number of data
lines from the controller compared to a system where multiple
control signals are required. This sharing is especially useful in
systems where reducing the number of control lines across an
isolation barrier is important. See Figure 82 for details of the
GPIOx pin options available on the AD7761.
Similarly, a GPIO read is a useful feature because it allows a
peripheral device to send information to the input GPIO and
then this information can be read from the SPI interface of the
AD7761.
AD7761
FILTER/GPIO4 11
MODE0/GPIO0 12
MODE1/GPIO1 13
MODE2/GPIO2 14
MODE3/GPIO3 15
ST0/CS 16
17 18 19 20 21 22 23 24 25
TO DSP/FPGA
Figure 82. GPIO Functionality
Configuration control and readback of the GPIOx pins are set
in Register 0x0E, Register 0x0F, and Register 0x10 (see Table 45,
Table 46, and Table 47 for more information).
Rev. A | Page 59 of 75