8-bit MicrocontrollersのトピックProblem with USB v2.0 for CDC Serial Demo Code

Problem with USB v2.0 for CDC Serial Demo Code

raven — Mon, 01 Sep 2008 13:34:51 GMT

I'm having a real problem with the code on cdc-serial-demo. I'm trying to configure the device descriptors on cdcs_usb_config.c specifically on the USB version part. The default is 0x0110 for USB ver1.1 but I want to make it 0x0200 for USB ver2.0. However when i tried this, a "!" symbol on the com port where the USB is connected appears and says

The device cannot start.(code 10)

So what seems to be the problem for this? Do i need to add additional codes or does the .inf file has something to do with this?

Please help me on this guys.

Thanks!

Re: Problem with USB v2.0 for CDC Serial Demo Code

fabio — Wed, 03 Sep 2008 22:09:04 GMT

Hello Raven,

The USB standard descriptors (as well as all requests and responses) use little-endian ordering, so the 2.00 must be written as 0x0002!

Also, I think you mistyped the default value (in my case it is 0x0101).

I tried it here and it worked ok.

Regards,

Re: Problem with USB v2.0 for CDC Serial Demo Code

raven — Thu, 04 Sep 2008 08:26:47 GMT

Hi Fabio,

But here is the trick part.. I've done an experiment with the hex code and here's what i've found out.

1. When I tried writing 0x01YY to the hex code (the YY is any number combination from 00-99), the

computer can recognize the device and the device works properly.

2. When I tried writing 0x00YY to the hex code (the YY is number combination from 00-99), the

computer can recognize the device and it works well.

3. When I tried writing 0xZZYY to the hex code ( the ZZ is any number combination from 02-99), the

computer cannot recognize the device and it says The device cannot start(code 10). What is the main

reason for this?