deskthority

I am currently working on a USB HID keyboard using an Atmel microcontroller. Everything is working fine but I usually use different keyboard layouts on different machines.

Now I started wondering if it would be possible to tell the host which keyboard layout to use, i.e. EN-US, so that keycodes will always get mapped on the right character on every machine. Any ideas?

The layout is usually just set in the operating system. In many operating systems you can have multiple keyboard layouts and swap between them (and/or language) with a key combination or tray icon (or similar). I think it is LAlt+Shift in MS Windows and Super+Space in Gnome in Unix/Linux viarants.

In the keyboard there is the bCountryCode field in the HID Descriptor but I don't think any OS actually acts on it, and it would be sent to the host only when the device restarts: so you would have to modify your firmware to do that as well.