Human interface devices: the descriptor heist

Today, GOOD build OUR own to input devices. And they will be easy has create And to write firmware For, they will work Perfectly, And they will be multiplatform. We can TO DO that with help of THE Human Interface Device (HIDDEN) standard, And by path of introduction, SO that You Never get confused by What A “descriptor” means, And GOOD build OUR own HIDDEN device — A Human Interface Device device. THE path We build them won't require while reading Features – instead, I will teach your how has fly HIDDEN descriptors Since existing devices, twist them For OUR purposes, And to use them In OUR devices has harness THE power of HIDDEN.

For decades NOW, It is has been possible has build A HIDDEN mouse Or keyboard by using A library Or two, And It is has been A gift from heaven For the Pirates all around THE world. However, these libraries are typically confined has A certain model And inflexible, And We the Pirates often go out of what is this expected. HIDDEN allow For a lot more that A simple keyboard Or A mouse. It is Why Today were building A touch screen – something not Again covered online Or by libraries.

HIDDEN let's allow You build devices that are friendly. They don't do it need Drivers, they are socket And play, And they TO DO What You to wait for them has TO DO. HAS It is heart, THE HIDDEN standard East as simple as East omnipresent. You can tunnel HIDDEN on USB, Bluetooth, I2C, And modern times Operating systems support all three of these. Today, let's go go through THE the basics of HIDDEN, And SO build A USB touch screen out of A SPI connected resistive touch screen, with help of THE usual RP2040+MicroPython combo. I will Also give You A toolbox For how has debug A Human Interface Device device as thoroughly as possible – specifically on Linux, showing all THE HIDDEN debug And introspection abilities that Linux given You. But How's it going work on the Windows Also through THE beauty of standardization.

Verification THE Map

There is enough A little guides on This subject by NOW, but of course, I will go In more detail, be more succinct, And give You tools that other guides don't do it to have. That said, You can always advantage Since several different guides has cross references on your journey, SO here is A Adafruit guide, And here is A little other those. In particular, they go further In HIDDEN descriptor structure And explain he In all THE detail You could to use When to understand out descriptors. Instead, I will give You A high level preview of HIDDEN, And demonstrate You that You don't do it need has fully to understand HIDDEN descriptors has create HIDDEN devices – You can To hack on them all THE same.

A report descriptor East A machine readable guide on how has analyze A HIDDEN pack ("report") Since your device. THE descriptor tell your Operating system which parts And bytes inside A HIDDEN pack match has What kinds of data. When A HIDDEN device East connected has your operating system, THE Operating system gets THE descriptor, bed he, learn What he can to wait for Since your device, And every time A incoming pack of data arrived, THE Operating system analysis your devices pack given THE Information In THE descriptor.