Interface adapter modules expose a set of General-Purpose Input/Output (GPIO) signals over the interface adapter module connector. These signals directly connect the carrier FPGA to the interface adapter module. GPIO signals provide support for user-defined functions, such as camera trigger, strobe, and other application-specific signaling.

Physical Layer

GPIO signals are single-ended lines that route directly between the PXIe-1480 carrier FPGA and the interface adapter module connector. The FPGA provides deterministic timing for reading and driving GPIO signals, making the signals suitable for latency-sensitive applications.

GPIO Direction

You can configure each GPIO signal independently.
  • When configured for input, the FPGA reads the signal driven by the interface adapter module or an external source.
  • When configured for output, the FPGA drives the signal.
If you leave a signal floating, or tri-stated, the signal is neither driven nor read.

GPIO Assignments

The interface adapter module design determines the purpose of each GPIO signal on the connector. Each channel dedicates some GPIO signals to the I2C interface with the SerDes. These signals are not available for general use.

The exact number and the assignment of user-accessible GPIO signals varies by interface adapter module. Refer to the documentation for your specific interface adapter module for pin assignments.

Determining Available GPIO Programmatically

The carrier module provides three I/O nodes per channel. Thee nodes indicate which GPIO signals are not reserved for other purposes.
Table 24. GPIO Availability
I/O Node Description
GpioInputMask Indicates which GPIO lines are available to read as inputs.
GpioOutputMask Indicates which GPIO lines are available to drive as outputs.
GpioOutputEnableMask Indicates which GPIO output enables are available.
The carrier firmware populates these nodes based on the interface adapter module EEPROM. The nodes provide a way to programmatically determine available GPIO without hard-coding device-specific assumptions into an application. The nodes do not replace the need to understand the pin assignments and capabilities of the specific interface adapter module in use.

GPIO-Over-Link Forwarding

Some interface adapter modules forward GPIO signals through the serial link. This forwarding makes GPIO from devices at the remote end of the cable appear as GPIO on the carrier FPGA. From the application perspective, these forwarded signals behave identically to directly connected GPIO signals. Your application doesn't require special handling.

Support in FlexRIO Interface Adapter Modules

Table 25. GPIO Support per Interface Adapter Module
Interface Adapter Module Model Serial Protocol GPIO Direction GPIO-Over-Link
IVN-14811

DSI-2 (TX)

OLDI (RX)

 Input and Output

Supported via FPD-Link IV

For pin assignments, refer to the Specifications document for the interface adapter module.