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gen4-IoD programmer on Custom Board

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  • gen4-IoD programmer on Custom Board

    I am interested in creating a daughter board for the back of my gen4_IoD-28T. I want to include the programmer functionality on my board. Do you have a reference design or other docs I can refer to?

    Thanks,
    Michael

  • #2
    Hi Michael
    Have you had a look in the Datasheet for the gen4-IoD range, as in the back are mechanical dimensions which show the Application PCB (daughter board) size to fit on the back of the plastics, as well as the schematics for both the module and the programmer itself.
    Regards
    James

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    • #3
      Doh! I didn't look carefully at the schematics and assumed it was just the display module itself.

      Thanks!

      Comment


      • #4
        WIndows Device Manager reports VID/PID of 10C4h / EA60h, which are the defaults for the Silicon Labs chip. Do you do any customizing? There's a 4.7uF cap between Vpp and GND which, according to the CP2104 data sheet, is needed only when you want to program the one-time programmable ROM. Also, GPIO0 seems to be used to flash the LED. By default, that pin is an input. Thus, I suspect you do indeed customize the chip. Can you please give specifics?

        Thanks,
        Michael

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        • #5
          The device is effectively customized in two ways. The 'max current' is set to the maximum allowable value, depends on both the device you are using and whether the system it is attached to actually uses this as to whether this is needed. Also the GPIO0 is configured to be used as an activity LED, so if you drop the LED you don't need to do this.
          Mark

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          • #6
            Is there anything special about the CP2104? I'm not fond of hand-assembling boards with QFN packages. It looks like you are using the TX, RX, DTR and RTS signals. Any reason why I couldn't use a different USB/UART chip such as the ever-popular FTDI FT260? That chip even has a GPIO pin that can flash the TX LED just like the CP2104.

            Thanks,
            Michael

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            • #7
              You need a device that has DTR output which can be manipulated using normal Windows interfaces.

              This device looks like it has DTR, but its operation isn't quite described the way I'd prefer.
              Mark

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              • #8
                Can you be a little more specific, please? What is the DTR issue? Isn't the manipulation of DTR encapsulated by the driver, using the EscapeCommFunction API? Is this a chip issue or a driver issue?

                Thanks,
                Michael

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                • #9
                  Yes, it should be via the EscapeCommFunction API, and implemented that way by the driver.

                  But reading the datasheet it isn't quite worded that way.

                  Regardless, you will always need to test.
                  Mark

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