AD4134 datasheet(73/92 Pages) AD

73 / 92 page

Data Sheet

AD4134

GPIO FUNCTIONALITY

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Rev. 0 | 73 of 92

The AD4134 has additional GPIO functionality when operated in

SPI control mode. This fully configurable mode allows the device

to operate eight GPIOs, thus making the AD4134 work as an

SPI-based GPIO expander. The GPIO 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, amplifiers, multiplexers, and buffers over the

same SPI as the AD4134. Sharing the SPI 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.

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 of the AD4134.

The GPIO pins can be used as general-purpose inputs or outputs.

The GPIO_DIR_CTRL register configures the individual pin as an

input or output. The GPIO_DATA register reflects the status of the

pins when configured as inputs or the user can write to this register

to set the pins when configured as outputs (see Figure 126).

PIN ERROR REPORTING

Additionally, GPIO7 can be used as an output to report any of the

diagnostic errors by enabling Bit ERR_PIN_OUT_EN. Register ER-

ROR_PIN_SRC_CONTROL controls the type of errors that can be

reported on this pin. If multiple types are selected, the output is a

logical OR of all the selected errors.

GPIO6 can be used as an error input from any other device by

enabling the ERR_PIN_IN_EN bit. The status of this bit can be read

using the ERR_PIN_IN_STATUS bit.

The GPIO7 output is a logical OR of all the selected er-

rors, as per the ERROR_PIN_SRC_CONTROL register and the

ERR_PIN_IN_STATUS bit.

Figure 126. AD4134 as SPI GPIO Expander

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