Saturday, September 13, 2014

"I love playing. The keyboard is my journal."

Well, now we can join Pharrell Williams and play the Bitbox with an USB Keyboard since commit 3a983ff

The USB code can now read USB keyboard and produce events, and a small function has been added to emulate the gamepad with a keyboard, so to get basic keyboard support you need to add one line in games. Or just check for the events yourself.

Keyboard can be read from an application by using the event_get() function , which returns a (possibly empty) event, check for e.type = evt_keyboard_press or evt_keyboard_release events, and then get the modifiers (Control, Shift...) state in e.kbd.mod and the keyboard code e.kbd.key bytes.

The code themselves are position-dependent, not letter-dependant (by example on a QWERTY keyboard the Q letter has the same code than the AZERTY 'A' letter, thanks to the USB norm for that), so if you want to type some text, use the appropriate translating tables. (there are two key maps available on the kernel for now, QWERTY and AZERTY).

All key codes ("Usages") can be found on the HID Usage Tables, Usage Page 7.

All of it is defined in the bitbox.h file.

The bootloader 2 has been upgraded with it, by additionally displaying the last key pressed or released on screen. Also, the examples now include keyboard usage.

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