• calcopiritus@lemmy.world
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    6 days ago

    You can definitely send arbitrary data from host to device and the other way around with USB HID. Many keyboard/mice have programmable macros. That is only possible because the host can send arbitrary data in a proprietary format (to save the macros on-device) and the device can too (to tell the software what the macros contain)

    • Aceticon@lemmy.dbzer0.com
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      6 days ago

      That’s not part of HID, it’s a second, usually custom (though it can also be a different USB standard that allows for uploading data to the device, such as USB-DFD), USB endpoint on the device.

      In the USB-HID spec the only data that you can send from Host to Device is indicator status (used for example to determine which keyboard LEDs are ON)