Installing the CM3

Connections to the CM3

The CM3 card has a few external connections. The power connector (on board revision 4) uses a Tyco Electronics 2 pin surface mount header, the mating side to this header is ​here. Using vampire clips connect the positive power cable to the standby voltage from the node power supply (PS), which is typically the purple cable, or pin 9 on the 20(+4) pin power power connector. The ground wire can be connected to any of the PS ground cables.

There are two cables that should come out of the J6 header. The first cable is the 'power switch' cable (two wires) and should be plugged between the mother board (MB) power button pins (usually found on the 'front panel' header) and pins 1 & 2 on the J6 header. This cable replaces the need for a physical power switch. Similarly the 'reset switch' cable runs between pins 3 & 4 on the J6 header and the reset switch pins on the same 'front panel' header on the MB.

The serial header is used to connect to the serial port on the mother board, the J4 header is another way of accessing the serial lines and uses a standard 2x5 100mil pin spacing. In the present configuration the serial cable should be a straight cable, and not a crossover (or null modem). If you wish to use a null model cable the resistors R17 and R18 must be populated, and R15 and R16 removed. The last connection that needs to be made is the power monitoring cable, which is the floppy power cable from the PS. This feeds the voltage that the CM will monitor to determine the state of the node.

Turning the CM3 on

The Lantronix Xport AR does not refresh its IP address when an ethernet cable is plugged in to is it important the that MAC address of the device already be in DHCP with the appropriate address, and that the ethernet cable be already plugged in when the device is powered on. If it is not in DHCP and plugged in to the network it will default to some unknown IP address, and will not change until reset or power cycled.

When the CM3 turns on the software will start sending UDP packets to the CMC and waiting for responses as well as monitoring the hardware status of the node. This will only happen after the Xport AR has gone through it's own boot sequence, which includes getting its IP address from the DHCP sever and booting into the custom code loaded with the CM3 image.

Using the CM3

The CM3 board, once properly plugged in and powered up will find an IP address and then load the custom software written automatically. Once the node has and IP and is powered up it should start communicating with the CMC right away. For details on the way the software works please refer to the ​Software Description or look at the code repository in the SVN. The UDP commands are described in more detail in the software description.

UDP

UDP is the primary way to control the node, and is always running in the software. UDP is used to communicate between the CMC and the CM, each command from the CMC has a ACK (in software) to signify that the command was received and processed. UDP allows for the powering on, off, and reset of the node, as well as a reset command to the CM and enabling and disabling the update feature.

Serial to Telnet tunnel