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

A vehicle or machine with more than one CAN network needs a controller that can sit on each of them without linking their grounds. The JNMM-4LP-XT is the quad-port PC/104-Plus build in the Diamond Systems JANUS-MM-LP series, an isolated CAN bus module that gives a PC/104-Plus stack four CAN 2.0B ports and 16 digital I/O lines on one board.

An FPGA core houses the CAN controller and digital I/O logic, with data rates up to 1 Mbps on every port. The JNMM-4LP-XT handles standard 11-bit and extended 29-bit identifiers, with expanded message queues of 16 eight-byte transmit and 31 eight-byte receive entries and 16 receive filters, which helps the host keep up with busy buses. The host interface selects PCI or ISA automatically on the PC/104-Plus stack.

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

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