CUSTOMHID_SIZ_REPORT_DESC larger than 255

gurnett2 · ‎2012-03-09

Posted on March 09, 2012 at 12:29

I have a hid report created using descriptor tool 2.4. The final descriptor size is 289. which appears to be to large (hid not detected). If I cut a few reports out so the size becomes less than 256 it works fine. Is it possible to increase the limit or do I need to do something else to get around this.

I'm using STM32_USB-FS-Device_Lib_V3.3.0

Thank you

Michael

tsuneo · ‎2012-03-09

Posted on March 10, 2012 at 02:27

Fix wItemLength field of HID descriptor (in the config descriptor set), as follows

usb_desc.c

#define WBVAL(x) (x & 0xFF),((x >> 8) & 0xFF) // <--- add this definition

const uint8_t CustomHID_ConfigDescriptor[CUSTOMHID_SIZ_CONFIG_DESC] =

{

...

/******************** Descriptor of Custom HID HID ********************/

/* 18 */

0x09, /* bLength: HID Descriptor size */

HID_DESCRIPTOR_TYPE, /* bDescriptorType: HID */

0x10, /* bcdHID: HID Class Spec release number */

0x01,

0x00, /* bCountryCode: Hardware target country */

0x01, /* bNumDescriptors: Number of HID class descriptors to follow */

0x22, /* bDescriptorType */

// modify these two lines

// CUSTOMHID_SIZ_REPORT_DESC,/* wItemLength: Total length of Report descriptor */

// 0x00,

WBVAL( CUSTOMHID_SIZ_REPORT_DESC ), /* wItemLength: Total length of Report descriptor */

Tsuneo

gurnett2 · ‎2012-03-10

Posted on March 10, 2012 at 18:19

Thanks

I figured it out an your suggestion is pretty much what I did which confirms that I was on the right track

-Michael

tsuneo · ‎2012-03-10

Posted on March 10, 2012 at 18:58

> your suggestion is pretty

Thanks,

but such a macro is a standard way to fill two-bytes numbers into descriptors.

You'll see this way in many USB examples from other resources.

If ST team would learn the standard way, you shouldn't be trapped.

Tsuneo