Bios commands and usb

Hi, i want to communicate with usb device using bios command.I know that bios support hid class and mass storage class, but does it support other usb classes (and is it full support )?is it possible to communicate with usb device by sending to usb port bytes, treating classes as unneeded element. how it is during pc initialization (before system starts) is usb device classified (hid, cdc, msd...) or is it treated as a device with byte exchange without class abstraction layer? thanks in advance

Reply to
mmmm
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mmmm schrieb:

No.

No.

Keyboard and mouse have a special, simplified "boot" protocol, and maybe support for hubs is left out. Otherwise it's just standard USB.

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Mit freundlichen Grüßen

Frank-Christian Krügel
Reply to
Frank-Christian Krügel

element.

Is above possible during pc initialization (before system starts)?

Could you give me links with some information about this subject?

Reply to
mmmm

mmmm schrieb:

No.

formatting link
has got the complete specifications.

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Mit freundlichen Grüßen

Frank-Christian Krügel
Reply to
Frank-Christian Krügel

Well, sort of. You would need to write your own driver for the USB host adapter. Then you could take raw USB packets to the device, utilizing whatever capabilities it has.

But you would need a driver for each potential USB host adapter your software might encounter. Usually the operating system takes care of such hardware localization for you, and presents you instead with a consistent programming model, the weight of which you seem to be wanting to avoid.

So my answer would be - "yes" provided that you are willing to invest a lot of work in developing a solution that only works on a narrow selection of hardware. In the embedded world, there are circumstances where that could be contemplated, but loss in the duplication of existing effort and the loss of flexibility to easily move to other hardware which you might otherwise have had.

Reply to
cs_posting

Going farther in this topic how it is with caps lock on and off before system starts. When i turn the caps lock or other lock keys, pc sends message to keyboard and the led turns. what is responsible for sending this message? how it exectly works?

Reply to
mmmm

If "legacy support" is active in your BIOS setup, the "system management mode" firmware will do this for you (=emulating a PS/2 keyboard)

jbe

Reply to
Juergen Beisert

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