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Looking for programmable device (FPGA, CPLD...???)

Discussion in 'Electronic Design' started by McWired, May 2, 2007.

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  1. McWired

    McWired Guest


    I want to build a board to connect a microcontroller to a TFT
    display. The board consists of the microcontroller, a programmable
    device and a FPC connector for the screen. Since I want to test
    different screens, and each of these has a different pinout and line
    number for the FPC cable, the programmable device is needed to
    reroute the lines from the microcontroller and the power supply
    lines. Basically, it should consist of a latch block to hold the
    address lines, bidirectional data lines and control/status lines, and
    power supply including ground. The output current for the supply is
    maximun 50mA, and the switching frequency at about 5Mhz.

    The FPC connector will be soldered according to the cable size, since
    the board will have a large array of connection pads to accomodate
    this part.

    I've never try a FPGA neither a CPLD so that's new field for me, but I
    think that is the type of component that I should use to interface the
    microcontroller with the screens. Any comments will be highly

  2. Andrew Holme

    Andrew Holme Guest

    An FPGA would be overkill if your design only required a small percentage of
    the chip's resources. It sounds like a CPLD would be more than adequate for
    the job, and would have the advantage of retaining its configuration when
    power is removed, although, if you used an FPGA, and you loaded the
    configuration data from the microcontroller, you could possibly avoid the
    hassle of needing a boot PROM. You can download the vendor's development
    software (Altera Quartus or Xilinx ISE) and try compiling a prototype
    project before making a final decision. Use Verilog.
  3. McWired

    McWired Guest

    When using one of this programmable devices, is it posible to transmit
    a voltage level (5V or 3.3V) from one input to an output, so I can
    reroute the Power Supply lines.?

  4. jasen

    jasen Guest


  5. Andrew Holme

    Andrew Holme Guest

    No. PLD outputs are standard logic outputs with limited current drive
    capability. I suppose you could take a few hundred microamps or even a
    milliamp or two; but it would be bad practice. You can't route different
    voltages. Outputs belong to a particular I/O bank which has power supplied
    from a dedicated VDD pin or pins.
  6. joseph2k

    joseph2k Guest

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