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Combination Module: 2 Ch. Dual-Redundant MIL-STD-1553 & 8 Ch. ARINC 429/575 Communications Interfaces

The CM5 provides a combined function alternative which mitigates SWaP-C system integration and configuration challenges. The CM5 function essentially combines two of NAI’s popular functions on a single-slot function module:

MIL-STD-1553 Communications Interface : The CM5 smart function provides a MIL-STD-1553 interface Bus Controller (BC), Remote Terminal (RT) or Bus Monitor (BM) function (programmable per channel). The IP/Core MIL-STD-1553 firmware supports NAI software/API Assisted Mode Capability (AMC).

ARINC 429/575 Communications Interface : The CM5 smart function provides a fully programmable ARINC 429/575 communications interface. ARINC 429 (and legacy ARINC 575) is a data transfer standard for aircraft avionics. It uses a self-clocking, self-synchronizing data bus protocol. The physical connection wires are twisted pairs carrying balanced differential signaling. Data words are 32 bits in length and most messages consist of a single data word. Messages are transmitted at either 12.5 or 100 kbps to other system elements that monitor the bus messages. The transmitter constantly transmits either 32-bit data words or the NULL state. A single-wire pair is limited to one transmitter and no more than 20 receivers. The protocol allows for self-clocking at the receiver end, thus eliminating the need to transmit clocking data.

  • Independent (dual-redundant) MIL-STD-1553 interface channels: Bus Controller (BC), Remote Terminal (RT), and Bus Monitor (BM) or RT/BM combined mode operation
  • Assisted Mode (AM)
  • 64KB onboard memory per channel
  • IP-core register-compatible with DDC™ family of devices
  • Ability to set message retry policy
  • Message scheduling capability
  • Asynchronous message capability
  • Message FIFO capability

Number of Channels: 2 Dual-Redundant (Transformer-Coupled)
IP Core: IP-core compatible with DDC™ family of devices. 64KB onboard memory per channel.
User Interface: NAI Assisted Mode Capable (AMC) interface for rapid setup, transmission and/or reception of packets.
UI Onboard RAM: Three 1K words FIFOs per channel
Operational Modes: Programmable as Bus Controller (BC), Remote Terminal (RT), Bus Monitor (BM), or BM/RT
Output Signal: ~24 Vp-p, as per MIL-STD-1553
ARINC 429/575
Input/Output Format: Eight channels, programmed for either Rx or Tx per channel
Frequency: 100 kHz or 12.5 kHz operation (programmable)
Buffers: 255 message FIFO Rx or Tx FIFO buffering or scheduled transmits; SDI/Label Filtering
Self-Test: Loopback test
Format: AR429 or 575 programmable/channel
ARINC 429 reserves bit 32 for parity, while ARINC 575 can use bit 32 for either parity (when BNR) or data (when BCD).
Signal Levels Specifications ARINC 429 ARINC 575
Mode of Operation Differential Differential
Data Rate 100 kHz 12.5 kHz
Driver Output Signal Level (Min Loaded) ±10.0 V ±10.0 V
Receiver Input Voltage Range -17 V to +17 V -17 V to +17 V
Receiver Input Resistance (Ohms) 15 K 15 K
Power: 5 VDC @ 1150 mA
+/-12V @ 0.15 A
MIL-STD-1553, estimated at 100% duty cycle (1-channel)
Weight: 1.75 oz. (50 g)
Block Diagram
2/4/2022 12:29:39 PM
12/14/2023 3:51:39 PM
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NAI’s Configurable Open Systems Architecture™ (COSA®) offers a choice of over 100 smart I/O, communication, and Ethernet switch functions, providing the highest package density and greatest flexibility of any multifunction I/O board in the industry. Preexisting, fully-tested functions can be combined quickly and easily in an unlimited number of ways. Choose the ideal platform for your application below. Each I/O function has dedicated processing, unburdening the system Single Board Computer (SBC) from unnecessary data management overhead.

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