Electrical Specifications

RS-422A Differential Signals

Flex1553-PCIe, FlexMulti, IPM-DIO-24 and IPM-ASYNC supports differential discrete signals.

16 differential discrete inputs and 16 differential discrete outputs are available on Flex devices. The transceivers used are compliant with EIA-422/485 specification. On FlexMulti devices, 8 discrete inputs and 8 discrete outputs from multi enhanced module can have their electrical settings modified (voltage amplitude and offset, receive threshold voltage, ...). The dedicated discrete inputs and all discrete outputs can also be used as unipolar. In input, it can be done by using the positive line for signal and set the negative line to ground. A dip switch must be set to change between differential and unipolar. The input threshold voltage is 1.65V and higher for logic high and 1.4V and below for logic low. In output, the positive line can simply be used as signal.

28V Avionic Signals

FlexMobile, IPM-DIO-48 and IPM-DIO-48-FIFO supports 28V avionics discrete signals.

Edge Detection

A signal edge is a transition in a digital signal either from low to high (0 to 1) or from high to low (1 to 0). It is called an "edge" because the square wave which represents a signal has edges at those points.

The following edge transitions can be monitored and/or controlled by MAXT's devices:

• Rising edge
  
  Transition from low to high. It is also referred as positive edge. When a circuit is rising edge-triggered, it becomes active when its clock signal goes from low to high, and ignores the high-to-low transition.
  
  
• Falling edge
  
  Transition from high to low. It is also known as the negative edge. When a circuit is falling edge-triggered, it becomes active when the clock signal goes from high to low, and ignores the low-to-high transition.