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Programming cable requirement

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  • Programming cable requirement

    Good morning,

    Is it absolutely mandatory to use the official 4D programming cable ? As after all, it's a serial cable.

    Reason I'm asking: I just received my uoled display for prototyping, and of course I completely forgot about the cable. I do have a FT232 cable lying around, with a jumper to select power supply level (3.3V vs 5V).

    When I use it (and connect it the proper way), at plug time the "comms" tab does detect the display correctly, but any subsequent scan (and of course upload) fails ("Device not responding"). If I reverse TX/RX of course I don't get any response even at first plug.

    So what is odd is that the cable is able to detect, but fails to communicate afterward. It always detect at first communication.

    Revision displayed by detection does match displayed information once screen has powered up (SPE2 rev 1.1, Pmmc rev 2.4, com 9600)

    I would REALLY welcome to be able to use my cable. Otherwise I need to order one, which means an additionnal delay (not to mention 25 euros +shipment for a simple USB-serial cable - I paid mine about 3 euro... hefty margin).

    Thanks for the help


  • #2

    Yes you need to use the official programming devices, as the 4D processors are our own, and require a specific programming method. Your generic FT232 cable most likely does not control the reset the same way as ours, which could brick your processor if you are not careful. This is spelled out numerous times in our datasheets. Its not about us trying to make you buy another device, is that other devices on the market don't work.

    TX and RX is only one part of the programmer, controlling the reset and putting the processor into the correct sequence for programming is the other. Your FT232 cable may use RTS to control reset, maybe its via a series capacitor like an Arduino, maybe its something else, ours does not use this and uses DTR. Not all devices are the same so the assumption something generic should work, is an incorrect one.

    I would highly suggest you stop using this cable and buy the correct programmer for the device.

    I hope that helps



  • #3
    Thanks, I'll look at options.



    • #4
      And indeed, based on these schematics, I see that you are inverting the DTS signal through a NPN transistor. Also as I did not know you were using DTR, on my cable the DTR signal is not connected to the header (although there is a through hole pad so I can add a header).

      Ah well, if I have a transistor lying around I'll whip something up, otherwise I'll just buy your cable



      • #5
        Good morning, just managed to get my adapter working. Given that it's the exact same USB-serial chip, I followed your reference schematics on a breadboard (ugly wiring...), and it did work like a charm.