Generating PPS from an FTDI FT2232H Mini Module

Discussion in 'Embedded Systems and Microcontrollers' started by Klen, Mar 13, 2011.

  1. Klen

    Thread Starter New Member

    Mar 13, 2011
    1
    0
    Hello everyone

    I am relatively new to the engineering field and have virtually no prior practical experience nor knowledge. Hence, please bear with me if my question seems too trivial or makes little sense.

    I have been asked to generate a Pulse per second (PPS) signal from an FTDI FT2232H Mini Module. The programming has to be done in Visual Basic (C++ or C#).

    One probable solution which I think could work is something like:
    ****************************************
    FTDI Clock = 30 Mhz = 3,000,000 cycles per second
    If Baud = 100, => 10 ms = 300,000 cycles.

    Default Value: PPS = 0; counter = 1;

    if rising_edge (FTDI_CLK)
    if (counter > x) /* x can be changed for a different duty cyle. For eg: x = 3 will give a rise time of 30 ms to the PPS. */
    PPS = 0;
    if counter == 300,000
    counter = 1;
    PPS = 1;
    else
    counter++;
    *******************************************
    Unless I have gotten the whole concept wrong, the above code should be logically correct. But even then, I am at a loss as to how to detect the rising edge of the FTDI clock (which again I am only assuming has a clock of 30MHz)

    Any type of help will be very useful right now.....its very urgent! I am as lost as one can be!
    Firstly, I am not able to locate a clock on the FTDI from which I can generate a PPS signal. I am looking at some timer/counter possibilities, but I am not getting very far either. Any suggestion as to how to generate pulses per second without a reference clock???


    Best Regards and Thanks in advance
    Klen
     
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