Flexible I/O Expansion for Avionics Systems

Aitech’s A175 I/O Expansion Subsystem is a small add-on unit for avionics systems specially designed to:
• Expand I/O capabilities of existing avionics systems
• Support Avionics I/O having sensitive signals

With its high variety of I/O interfaces, small form factor, low power dissipation, and standard
MIL-STD-1553B avionics bus interface (RT), the A175 handily meets these requirements. It can be used to
expand the I/O capabilities of any avionics computer with a standard MIL-STD-1553B interface.

For sensitive signals, the unit can be mounted in close proximity to sensors enabling short wiring to ensure
maximum signal integrity and minimum signal loss.

The A175 is ideal for expanding the capabilities of existing avionics systems, with inherent scaling
capability provided by additional units that can be added as slaves to the main avionics computer. The
number that can be added is limited only by the capabilities of the main avionics computer.

All I/O interfaces are implemented in the unit’s FPGA, with only the physical layers being dedicated
devices. This minimizes power consumption, and enables convenient customization of the unit to meet
specific applications.

To ensure highest reliability, the A175 includes extensive Built-in Test (BIT) capabilities. Each discrete
output line is routed to a dedicated discrete input to enable loopback testing. (These dedicated discrete
inputs are in addition to the discrete inputs available at the I/O connectors). The FPGA compares the input
and output signals and writes a health status bit for each channel to registers in the FPGA that are
accessible to the avionics computer CPU via the MIL-STD-1553B link.