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We will try to post mostly about arduino high power led shield and discuss related topic such as general high power leds, i2c communication using  Arduino micro-controller boards and perhaps other micro controller boards.

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  1. Hello,
    I have been using MCP4728s using your code. They work well for an application where I need to control the analogue output with reasonable accuracy and stability. I am now trying to change the address of an MCP 4728 using your code. I don’t appear to be able to get it to work at all. Should the default address be zero or 7. I think that if the code returns 7, then I have not contacted the MCP device properly.

    Can you confirm which software version works and which doesn’t as there is reference to a problem with this but I am not sure which is good and which is bad.

    I have confirmed that the MCP is connect and working. it is at address 0x61 as confirmed using an I2c scanner.

    SCL and SDA are connected to pins A5 and A4 which should be pins 19 and 18 of the arduino uno.

    the response I get from the serial interface is:
    Changing Device ID of MCP2728 for multiple shield stacking

    Check following carefully !
    1.Just one RGB LED shield connected to Arduino
    2.Make sure A4, A5, GND pins are connected to Arduino
    3.Make sure LDAC jumpuer on the shield is changed from – to +

    LDAC pin seem to be connected

    Now checking current device ID of mcp4728…
    Current device ID of MCP4728 = 7

    Checking communication to mcp4728…
    Sucessfully communicate with mcp47280

    Writing new device ID to mcp4728…

    Checking changed device ID of mcp4728…
    Device ID of mcp4728 is not matched with current ID
    Please, check instruction and try again
    7

    I am not using your shield but just an MCP4728 device wired up. I know that it works because my test code sends out the correct voltages from channels 0-3 on the device.

    Hope you can help.
    B
    Nick

    • Hi Nicholas,

      I apologize for the very long delay in my answer. It appears I need to check my WordPress settings as there are several posts that I was not notified of.

      Not sure this addresses the problem, but the programming of the I2C address only works with an Arduino Uno. Teh sketch uses a software I2C version and the MCP2728 requires a very specific timing that could not be achieved using just the wire library.

      Ive tried to get that to work with a Teensy ++ 2 which is also based on Atmel 8-bit micro controllers but so far I’ve only gotten this to work on an UNO.

  2. Hello, I’m interested in your LED shield, I saw it on Tindie. However Tindie has not responded to my requests to fix my registration yet, but I’d like to know, are these available for purchase? And could you please say exactly which pins on the UNO are required for it?

    Thanks,
    Stephen

  3. Also can you say what the voltage drop is from input to output? If I have a 12V supply, can I drive an LED that requires 10.3v ? Thanks!

  4. Hi Stephen,

    I am sorry to say that I never saw this post. I will need to check my WordPress settings.

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