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Thread: Teensy 4.1 multiple devices

  1. #1
    Junior Member
    Join Date
    Nov 2012
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    Germany
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    Teensy 4.1 multiple devices

    Hi,

    i am going to create a rgb keyboard with oled display for profile switching and notifications.

    i use the following devices:
    - a 7pin spi oled. (the pins are labled: GND VCC SCL SDA RST DC and CS)

    - furthermore i use a 6 rows (digital outputs) x 21 colums (digital inputs) keyboard matrix that requires 27 pins total for 126 keys.

    - the usb host socket for game controller input. (pins known)

    - the onboard sd-card (pins known)

    - the default led (pin 13 fixed)

    - and ws2813 led strip with 120 leds. connected via 74HCT245 buffer chip/s ( i have read the teensy can break the max bandwidth barrier of the strip by providing multiple strips with fewer leds on multiple pins, maybe 6, for every row one pin? but they are limited to a specific range of pins even on the teensy 4.1 yes? is DMA possible?

    my problem is that i don't know the best pinout for all these devices.

    if i use pin 0-29 (-PIN13 LED and -PIN 3.3v) for the keyboard i lose hardware spi or am i?: cs1 miso1 cs0 mosi0 miso0 mosi1 sck1 and sck0 (led) so i can't use them.

    if i want to use most available hardware acceleration features available (SPI/DMA) which pins should i choose for all devices?

    do i have to consider any of my thoughts? or can i add anything on any pin? i might be lost here.
    is there a documentation about shared pins?


    a lot of question-marks here....

  2. #2
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    12,736
    @Kurte posted a doc with some detailed pin info : github.com/KurtE/TeensyDocuments/blob/master/Teensy4.1 Pins.pdf

    It might help confirming pin function to understand with what PJRC.com publishes on the card etc. And a printed copy could be marked up for with needed pins reserved and seeing what is left shifting the SPI[0,1,2] as needed to get the needed result.

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