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Thread: T-COMPUTER, teensy 4.1 based micro computer

  1. #1
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    T-COMPUTER, teensy 4.1 based micro computer

    The T-COMPUTER is an attempt to create a complete micro computer around the Teensy MCU.

    It is based on the Teensy 4.1 (my favorite MCU so far!)
    See the details of the project below.

    github.com/Jean-MarcHarvengt/T-COMPUTER


    It is fully open source and it is a DIY project so you are free to build it yourself for non commercial use of course
    Last edited by defragster; 06-23-2022 at 03:16 PM. Reason: edit URL to work

  2. #2
    Senior Member+ defragster's Avatar
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    Very cool. Edited p#1 link to work.

    What few pins are unused? Though PCB trace space looks tight to pull many out anywhere.

  3. #3
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    No free pin unfortunately , the pins exposed are in fact the 5 joystick inputs +2 user buttons on header pins + ground. If you don't connect the display, you can use like 5 extra including SPI and 3.3v. Yeah, forgive me for the track thickness, it is my first pcb... Gnd and 3.3v are a bit ticker.

  4. #4
    Senior Member+ defragster's Avatar
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    No complaint on the track width - one more PCB than I have done Was just noting so many traces that it didn't seem like many were unused, and not all were visible in images.

    Good note on what is available from Joystick, and the SPI pins, if not used.

  5. #5
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    Thanks for all the video work and sharing the design. I'd really like to build one. Does your board supplier (Aisler?) have your design files such that I could order a board from them myself? If not, I'll have some work to do to pick a board manufacturer and figure out which file(s) (gerber?) to send them.

    On a related note, I didn't quite follow how you made the keyboard overlay. Did you 3D-print it?

  6. #6
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    Sorry, just see this now...
    Aisler does not version control my Gerber files in particular. Normally drag and drop the zip file is enough. The overlay STL files are also on the GitHub. The frame and the keys. You need to print the 2 key rows STL file twice. Space and keypad only once. 3 pcbs on aisler will cost you 25 euros. I still would like to find out why VGA output is not that good on a bigger screen. I use a 10 inches yololo monitor and it is ok but I had bad results on a 20 inches.

  7. #7
    Senior Member+ MichaelMeissner's Avatar
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    Well I can imagine that for larger screens, particularly where the screen actually has more pixels. Something has to interpolate the image at one resolution to display it at another (and at times, you might have multiple translations). With the larger screen, you just notice the places where it has to interpolate the data.

    For example, lets consider three popular resolutions:
    • VGA: 640 x 480
    • 1080p: (sometimes called FHD): 1,920 x 1,080
    • 4K: 3,840 x 2,160


    This would mean every pixel of the VGA screen becomes 3 to 2.25 pixels of the 1080p screen, and it becomes 6 to 4.5 pixels with the 4K screen. As things are enlarged, some systems just duplicate the pixels, while some try to use AI to guess at what the screen is and convert the pixels to intermediate values.

    So in addition to sizes, notice that the VGA resolution has an aspect ratio of 4:3 while the 1080p and 4K resolutions have an aspect ratio of 16:9. When you convert 4:3 to 16:9, you either have to convert it to a smaller image and have black bars on the side (letterboxing) or you convert it to the resolution of the screen, making things wider (or taller). Sometimes you have an option of which aspect conversion ratio to use and whether to letterbox, sometimes you.

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