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
    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;
    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