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Thread: ILI9488_t3 and alternative pins for CS, DC

  1. #1
    Junior Member
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    ILI9488_t3 and alternative pins for CS, DC

    Hello!

    I am designing a new pcb and i really would like to use alternative pins for PINS CS & DC besides 9,10,15,21,22.

    So, is there any way i could do that?

    And, just for my information, why is this limitation? Simple digital pins aren't enough?

    Thank you in advance.

  2. #2
    Senior Member+ MichaelMeissner's Avatar
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    For Teensy 3.1, 3.2, 3.5, and 3.6, there are a few others, but the pins overlap, so if you choose one pin in the pair for DC/CS, you can't use the other pin for the SPI pins:

    Paul made this post that describe things:


    Here is his list:
    • The main problem is there really are only 5 of those special signals inside the chip. Four of the 5 can route to 2 different pins.
    • CS on pin 10 is the same as CS on pin 2.
    • CS on pin 9 is the same as CS on pin 6.
    • CS on pin 20 is the same as CS on pin 23.
    • CS on pin 21 is the same as CS on pin 22.
    • CS on pin 15 does not overlap with other pins.


    Note, Teensy 4.0 and 4.1 are very different. IIRC, the libraries that have been optimized will do the optimization if you use the favored pin(s) for D/C. Not counting the SD card and memory card SPI pins:
    • On Teensy 4.0, the D/C pin must be 10 for SPI, and 0 for SPI1;
    • On Teensy 4.1, the D/C pin must be either 10, 36, or 37 for SPI, and 0 or 38 for SPI1.


    Note, I haven't kept track of the recent changes to the display drivers.

  3. #3
    Junior Member
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    May 2016
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    Michael, thank you very much for your anwer.

    After i read Paul's post too, everything is very clear.

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