TM4C1233E6PM: TI's DriverLib Support for custom String Descriptor Requests

venkat ramana madishetty

Part Number: TM4C1233E6PM

Hi,

Am reaching out to inquire about the compatibility of TI's DriverLib with servicing custom string descriptors like 0xEE descriptor requests from the operating system.

Upon examining the bulk USB example provided in TI's DriverLib, I encountered a query regarding the custom index string descriptors like integration of "Microsoft OS string descriptors." Unfortunately, I couldn't locate an appropriate placement for these descriptors within the example.

Could you kindly provide insight into whether TI's DriverLib supports the servicing of custom descriptor requests? Additionally, any guidance or documentation would be greatly appreciated.

2 months ago

0 Charles Tsai 2 months ago

TI__Guru**** 165115 points

Hi,

TivaWare USB library does not support MS string descriptor extension. You are free to modify the driverlib. Please refer to this similar post.

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1171753/tm4c123ge6pm-can-usb-driverlib-handle-0xee-microsoft-os-descriptors?tisearch=e2e-sitesearch&keymatch=Microsoft%2520OS%2520string%2520descriptors.#

0 venkat ramana madishetty 1 month ago

Prodigy 30 points

Hi,

Thanks for the reply.

The question is not specific to MS string descriptor extension.
How can I assign a index number in the string descriptor table (Example String descriptor Index 0x40, 0x41) ?

Also the descriptor string table only accepts the entires of 16. Why only 16 string descriptors ? Can we extend the number of entries ?

0 Charles Tsai 1 month ago in reply to venkat ramana madishetty

TI__Guru**** 165115 points

Hi,

As I mentioned, you can modify the USB library to adapt to your requirements.

venkat ramana madishetty said:
Also the descriptor string table only accepts the entires of 16. Why only 16 string descriptors ? Can we extend the number of entries ?

I don't understand where the 16 is coming from. Based on the below code, the number of string descriptors is calculated. If you need to extend the number of entries, you can modify the code as I mentioned earlier.

#define NUM_STRING_DESCRIPTORS (sizeof(g_ppui8StringDescriptors) / \
sizeof(uint8_t *))

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TM4C1233E6PM: TI's DriverLib Support for custom String Descriptor Requests