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AdaFruit 3.5" TFT HAT and HDMI out working independently from each other.

KenKen New Member Posts: 48
While it's still a work in progress, I thought I'd share my progress on getting an AdaFruit 3.5" TFT HAT working independently from the HDMI output. I am using a multi-seat configuration to get the UP Board to have a regular keyboard-mouse-monitor setup working while independently having an Rii mini wireless keyboard (candy bar sized remote type with touchpad) work with the 3.5" display. The Mini-Keyboard controls keyboard and mouse functions for a session started on the 3.5" display, and a regular keyboard and mouse controls the HDMI homed session connected to a monitor. If and when kernel overlays are available, a variation of this would also allow independent touch control of the TFT while still having a full regular session on the HDMI. I think this would be useful for a media center application where the small display could be used as a status screen while say, Kodi runs on the main HDMI. Keyboard and mouse can be replaced by a remote and IR receiver, or anything X can use as an input device... in either case, TFT Session -or- HDMI Session. What I do not have working at the moment is hot-plugging of USB input devices, but I am working on that. Note that this is *not* a multi screen desktop, but 2 independent desktops running on the same Up Board, and they can be 'owned' independently, one can prompt for a login, one can auto login,

It's a fairly complicated setup, but really is just a few files and there is no compiling involved, just configuration. If this is something of interest to a broader audience I'll post it in the wiki once I have it all completely working. It's bits and bobs culled from a lot of different sources as multi-seat is supported by LXDE, KDE and several other environments, it's just not very well documented and takes a lot of trial and error to get it to work right, and every HOWTO seems to approach it differently and no one source seems to actually document a fully working configuration.


  • FernandoFernando New Member Posts: 22
    Hi Irwin.

    I think it would be useful for the community if you post your work in the wiki. Having two GUI session could be of interest in many scenarios.

    Thanks for sharing your findings with the community.
  • KenKen New Member Posts: 48
    I'll have to get my head back around what I did there. I've also done this on the Raspberry Pi, where I've just managed to get the little TFT HAT to respond to the touchscreen while HDMI uses a regular keyboard and mouse, which is kinda cool, though some of the Raspbianisms made it a fairly different procedure. If I ever manage to get the stmpe_ts touch screen drivers to work on the Up Board it should work there as well.
  • FernandoFernando New Member Posts: 22
    Hi Irwin.

    May I ask you, why are you using the stmpe_ts approach to making the touch screen work, instead of the ads7846 and ads7846_device modules used by notro and the Raspberry overlay?.

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