Changes between Version 11 and Version 12 of Hardware/jCM/dCM3/bHardware

06/13/11 21:05:31 (9 years ago)
Ilya Chigirev



  • Hardware/jCM/dCM3/bHardware

    v11 v12  
    3232 ==== Voltage Monitor ====
    33 The CM3 has a PC voltage monitoring chip installed, the
     33The CM3 has a PC voltage monitoring chip installed, the DS1780E+. This chip monitors the +5V, +12V, and temperature of the air in the case. The voltage levels are taken from the floppy connector (J2) which feed directly into the chip and communicates that information over I²C to the Xport AR. '''However''' the I²C is not active on the Xport AR, and so there is no way to effectively get accurate voltage and temperature data about the node.
     35The 'status' (i.e. on or off) of the node depends on the voltage levels of the power supply (PS), so as a work around for the lack of I²C support the current hardware version of the CM3 has the 5V line feed directly into one of the GPIO (set as an input) and if that is high the PS is on, and so the node is also on. Hopefully I²C will get some support in the future from Lantronix. Presently R4 and R14 is installed and R8 is left open. If I²C is to be implemented then R4 and R14 would have to be removed by hand, and R8 installed.
    3437 ==== RS232 Level Shifter ====
     38The RS232 level shifter takes the TTL compliant voltage levels from the Tx and Rx lines of the Xport AR and converts them to RS232 voltage standards (and vice versa). there is also 2 sets or resistors R15 & R16, and R17 & R18, which correspond to build in crossover or straight through signals. If R15 and R16 are installed then a straight cable is used to connect to the node serial port and if R17 and R18 are installed a null modem (or crossover) cable must be used. This is the sase for revision 4 of the CM3 board, the previous revision 3 had rotary switches rather than 0 ohm resistors. Also note that presently __the RTS and CTS signals have to be shorted manually on the 5x2 100mil header in order for serial redirection to work__. This was an oversight in the design and will be fixed in the next run.
    3639 ==== Solid State Relays ====