STM32F072 Discovery: USB Custom HID slowness

I found the answer to my issue. It turns out there is a setting for the ''Polling interval''. By default it is set to 32ms. It is found in usbd_customhid.c:

/* USB CUSTOM_HID device Configuration Descriptor */
__ALIGN_BEGIN 
static
uint8_t USBD_CUSTOM_HID_CfgDesc[USB_CUSTOM_HID_CONFIG_DESC_SIZ] __ALIGN_END =
{
0x09, 
/* bLength: Configuration Descriptor size */
USB_DESC_TYPE_CONFIGURATION, 
/* bDescriptorType: Configuration */
USB_CUSTOM_HID_CONFIG_DESC_SIZ,
/* wTotalLength: Bytes returned */
0x00,
0x01, 
/*bNumInterfaces: 1 interface*/
0x01, 
/*bConfigurationValue: Configuration value*/
0x00, 
/*iConfiguration: Index of string descriptor describing
the configuration*/
0xC0, 
/*bmAttributes: bus powered */
0x32, 
/*MaxPower 100 mA: this current is used for detecting Vbus*/
/************** Descriptor of CUSTOM HID interface ****************/
/* 09 */
0x09, 
/*bLength: Interface Descriptor size*/
USB_DESC_TYPE_INTERFACE,
/*bDescriptorType: Interface descriptor type*/
0x00, 
/*bInterfaceNumber: Number of Interface*/
0x00, 
/*bAlternateSetting: Alternate setting*/
0x02, 
/*bNumEndpoints*/
0x03, 
/*bInterfaceClass: CUSTOM_HID*/
0x00, 
/*bInterfaceSubClass : 1=BOOT, 0=no boot*/
0x00, 
/*nInterfaceProtocol : 0=none, 1=keyboard, 2=mouse*/
0, 
/*iInterface: Index of string descriptor*/
/******************** Descriptor of CUSTOM_HID *************************/
/* 18 */
0x09, 
/*bLength: CUSTOM_HID Descriptor size*/
CUSTOM_HID_DESCRIPTOR_TYPE, 
/*bDescriptorType: CUSTOM_HID*/
0x11, 
/*bCUSTOM_HIDUSTOM_HID: CUSTOM_HID Class Spec release number*/
0x01,
0x00, 
/*bCountryCode: Hardware target country*/
0x01, 
/*bNumDescriptors: Number of CUSTOM_HID class descriptors to follow*/
0x22, 
/*bDescriptorType*/
USBD_CUSTOM_HID_REPORT_DESC_SIZE,
/*wItemLength: Total length of Report descriptor*/
0x00,
/******************** Descriptor of Custom HID endpoints ********************/
/* 27 */
0x07, 
/*bLength: Endpoint Descriptor size*/
USB_DESC_TYPE_ENDPOINT, 
/*bDescriptorType:*/
CUSTOM_HID_EPIN_ADDR, 
/*bEndpointAddress: Endpoint Address (IN)*/
0x03, 
/*bmAttributes: Interrupt endpoint*/
CUSTOM_HID_EPIN_SIZE, 
/*wMaxPacketSize: 2 Byte max */
0x00,
0x01, 
/*bInterval: Polling Interval (20 ms)*/
//CHANGED FROM 0x20
/* 34 */
0x07, 
/* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, 
/* bDescriptorType: */
CUSTOM_HID_EPOUT_ADDR, 
/*bEndpointAddress: Endpoint Address (OUT)*/
0x03, 
/* bmAttributes: Interrupt endpoint */
CUSTOM_HID_EPOUT_SIZE, 
/* wMaxPacketSize: 2 Bytes max */
0x00,
0x01, 
/* bInterval: Polling Interval (20 ms) */
//CHANGED FROM 0x20
/* 41 */
} ;

Hi

76416

Tyurin.Denis_Mikhail

I was trying to reproduce the use case you refered to, on top of CubeMX4.

It seems that Denis answered vock's question. And for the comment for the bInterval, it has been changed on the latest releases :

As far as I understand your question, there is no remaining point.

Feel free to post any comment.

BR. Jeanne