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Thread: swap out ili9341 to ra8875 display

  1. #1
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    swap out ili9341 to ra8875 display

    I'm currently running a teensy 4.0 ..rev d audio board and an ili9341 display no issues.... touch working as well.. ... first time working with a TFT display so its a simple one ..

    I've been reading the wiki by Sumotoy trying to get my head around the 8875 interface ...

    yes I've purchased the 5" buydisplay ER-TFTM050A2-3-3661 with 5v/ 4 wire SPI ..(sitting in my hot little hands)

    If I reconnect the existing SPI pins and associated reset /interrupt which were connected to my ili9341 and swap the library out should this work?

    I'm currently running the conventional pins on the teensy4

    9 - DC
    10 - CS
    11 - MOSI
    12 - MISO
    13 - SCLK

    for SPI


    I realize I'll have to power the display with external power ..... not from the USB port...

    I'm trying to understand the potential conflicts with the Audio board and SPI ..( do I have to introduce the additional ttl logic for the tri-state SPI of the ra8875 if I'm using the audio board)

    I'm also having confusion in one portion of the wiki as there is a red note indicating the version of the display I have is 3.3v "only" and not 5v ... could use a little direction there ..

    Sorry for all the questions ...quite a step up from the ili9341 for me..

    Thanks in Advance...!!!
    Last edited by Keith_M; 07-14-2020 at 04:00 PM. Reason: additional info - redefined proper display model

  2. #2
    Senior Member+ KurtE's Avatar
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    You might do a search on RA8875 threads on this forum for additional information.
    Such as: https://forum.pjrc.com/threads/57280...rom-Buydisplay

    If I remember correctly there can be conflicts with the RA8875 MISO pin working with other SPI devices on the same SPI buss as theirs may not be tristated. There are ways around it, like maybe not connecting it or using an external buffer chip or...

    A few of worked on making sure it all works well with T4.x, and I believe the one we now have part of the released Teensyduino is pretty much up to date.

    SumoToy has not been active for several years. so I would not use the version up from his github. Usually the most up to date version is up in @mjs513 fork of it on github with the RA8875_t4 branch as the branch we made our changes in. Mine is usually in sync with that one as well.

    Good luck.

    As for hardware, I have ordered mine with the +5v version which has an onboard voltage regulator to 3.3v, and it has worked OK connecting to the USB pin of the T4...

  3. #3
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    Thanks KurtE .... will reference that library and see what happens ... if I can get it up on the T4 with the audio board running I'll be pretty happy ..

    good project while in lockdown ...lol

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