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ASD7846 problem

Laszlo Horvath
Prodigy 20 points
Other Parts Discussed in Thread: ADS7846

Hello!

First I used in my project an MXB7846 touchscreen controller. It was good, but it's no longer produced.

I finded the ADS7846, which is quite similar (PCB and the communication too). But when I tried to use it, the X position and the Y position were the same. When I touch the screen on a different locations, the data change, but the two channel give me the same value.

Thanks for help,

Laszlo

  • 0
    TI__Mastermind 20085 points
    Hello Laszlo

    Welcome to E2E, thanks for your interest in our products.
    How are you setting Digital interface? and, Could you provide me the setting register?

    Best Regards
    Jose Luis Figueroa
    Audio Applications Engineer | LPAA
  • 0 in reply to José Luis
    Prodigy 20 points

    Hello Jose!

    I use the normal SPI interface. I send 0xD8 or 0x98 to the controller, and then 2 x 8bit 0x00. By the MXB controller it worked well.

    I tried the other channels. On Z2 channel I get data which depend on the X coordinate, but it's not the real X coordinate. On this channel the data depend on the touch force. So I can't use it.

    The Y channel is perfect, as before.

    Thanks for help,

    Laszlo

  • 0 in reply to Laszlo Horvath
    TI__Mastermind 20085 points
    Laszlo,

    Z1 and Z2 channels are to measure touch-pressure. As you mentioned they can't be used to measure X coordinate.
    SPI interface configuration seems right. I think that the issue could be into the host.

    Best Regards
    Jose Luis Figueroa
    Audio Applications Engineer