Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first

Switching from a piTFT display to an external HDMI monitor.



  • Hello,

    I have recently installed RetroPie and it is delightful. It was first attached to a TV via HDMI and worked very well. I then installed a piTFT screen, as the final product will be a portable gaming device. That install went well and now the piTFT is the main screen. Perfect, almost. Ideally I'd like to use the piTFT when I'm travelling and a larger screen when I am not.

    As I understand the documentation that I read, the piTFT install uses Framebuffer Copy (fbcp) to mirror the piTFT to the HDMI, and I believe it's doing just that, but I get a "mode not supported" error on my TV, even when I remove the piTFT.

    After some more reading I think the problem is the resolution is set lower than my TV can process. So my first question is; are my above assumptions correct? And the second is; Is there a way I can tweak the resolution so that both screens will work (even if it's not at the same time) with minimal hassle to do the actual switch?

    I appreciate any advice given.

    Relevant data follows:

    Pi Model or other hardware: 2 B
    Power Supply used: Adafruit 5V PS
    RetroPie Version Used: retropie-4.1-rpi2_rpi3
    Built From: Pre made SD Image on RetroPie website - retropie-4.1-rpi2_rpi3.img
    USB Devices connected: Generic PS style gamepad, WiFi dongle, and wireless keyboard dongle
    Controller used: Generic PS style gamepad
    Error messages received: Mode Not Supported
    Log found in /dev/shm/runcommand.log (if relevant): N/A
    Guide used:https://learn.adafruit.com/running-opengl-based-games-and-emulators-on-adafruit-pitft-displays/pitft-setup (just the piTFT section)
    File: (File with issue - with FULL path) N/A
    Emulator: (Name of emulator - if applicable)N/A
    Attachment of config files: (PLEASE USE PASTEBIN.COM FOR LARGE LOGS)
    How to replicate the problem: See description and guide above



  • Turns out all I had to do was edit the /boot/config.txt and change the hdmi_group=2 to hdmi_group=1



  • bump!
    Thanks for the fix, T-Prime. This helped a lot! I just have one problem left with my PiTFT, which I don't know if you faced yourself. It seems that when I quit ES (but leave the Pi open), the terminal screen is not visible anymore. Do you know a way to bring it back? I made a quick video to illustrate the issue. I didn't show the hdmi screen, but it mirrors the PiTFT exactly:

    T-Prime hasn't logged in in 3 months, so anyone reading this who might know what to do or try, please let me know!



  • Solved it!
    After much tinkering, I realized my mistake. It's simple to avoid when you understand.

    To set up my PiTFT, I was using the easy install scripts from adafruit. My mistake was in the settings I set when running the following command: "sudo adafruit-pitft-helper -t 28c"

    The script asks you the following question:
    "Would you like the console to appear on the piTFT display?"

    I was answering yes, and THIS WAS THE MISTAKE. Answer NO!

    For the rest of thee tutorial, you can follow exactly the instructions given by adafruit. Here's an explanation of what was happening. When I answer yes to show the console on the piTFT display, what the script does is remove the console display from the HDMI output and forwards it only to the piTFT display. I don't know which file it modifies to do this, but this is the effect. When you do the "sudo bash pitft-fbcp.sh" command later in the installation instructions from adafruit, this command is the one that mirrors the content of the HDMI display to your piTFT. Since I unknowingly had removed the console from the hdmi display as described above, the piTFT did not show the console anymore: it only showed what appeared on the HDMI!

    If you want your PiTFT to work alongside the HDMI display, make sure you set hdmi_group=1 instead of =2 in /boot/config.txt as @T-Prime mentioned above.

    I'm glad this problem was sorted out! What's even cooler is that the resolution is automatically adapted when you boot retropie depending on if an external hdmi display is connected or not.



  • @t-prime
    So, while I haven't begun with setting up my project, i still want to ask to be sure, as I'm quite new to all of this... (°_°). To keep the "fully working" hdmi, I can still follow the tutorial by adafruit (https://learn.adafruit.com/running-opengl-based-games-and-emulators-on-adafruit-pitft-displays/pitft-setup) and use their script, but I'll have to answer NO once I'm asked as you described and change the .txt file, right?



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