Diamond Systems JANUS-MM-LP : JNMM-4L-XT 4 Port Isolated CAN Bus PC/104 Module with 16-Channels Digital I/O

Plenty of rugged PC/104 stacks run on the ISA bus, and they may need to reach as many CAN networks as a newer system. The JNMM-4L-XT is the quad-port PC/104 build in the Diamond Systems JANUS-MM-LP series, an isolated CAN bus module that adds four CAN 2.0B ports and 16 digital I/O lines to a PC/104 stack.

An FPGA core holds the CAN controller and digital I/O logic and supports data rates up to 1 Mbps. Every port on the JNMM-4L-XT handles standard 11-bit and extended 29-bit identifiers, with expanded queues of 16 eight-byte transmit and 31 eight-byte receive messages and 16 receive filters for busy buses. The module connects to the host over the PC/104 ISA bus.

Each port has its own ADM3053 combined isolator and transceiver, giving 500 V isolation port to port and port to host, with jumper-selectable biased split termination to reduce noise. The 16 digital I/O lines sit in two 8-bit ports with software direction control, jumper-selectable 3.3 V or 5 V logic and pull-up or pull-down resistors. Latching connectors keep cables in place under vibration. The JNMM-4LP-XT carries the same four ports on PC/104-Plus, and the JNMM-2L-XT is the two-port PC/104 version.

Power is 5 V DC from the stack. Diamond Systems tests the JNMM-4L-XT for -40 to 85 °C operation at 5 to 95% humidity, non-condensing, and specifies MIL-STD-202G compatible shock and vibration. A basic CAN driver with APIs and a monitor program covers Windows Embedded Standard 7 and Ubuntu Linux 12.04 LTS, with a digital I/O cable and one CAN cable per port available from Diamond.