LUFA Library  151115
USB_ClassInfo_HID_Device_t Struct Reference

HID Class Device Mode Configuration and State Structure. More...

#include <HIDClassDevice.h>

Data Fields

struct {
   uint8_t   InterfaceNumber
   void *   PrevReportINBuffer
   uint8_t   PrevReportINBufferSize
   USB_Endpoint_Table_t   ReportINEndpoint
struct {
   uint16_t   IdleCount
   uint16_t   IdleMSRemaining
   uint16_t   PrevFrameNum
   bool   UsingReportProtocol

Detailed Description

Class state structure. An instance of this structure should be made for each HID interface within the user application, and passed to each of the HID class driver functions as the HIDInterfaceInfo parameter. This stores each HID interface's configuration and state information.

Due to technical limitations, the HID device class driver does not utilize a separate OUT endpoint for host->device communications. Instead, the host->device data (if any) is sent to the device via the control endpoint.

Field Documentation

struct { ... } USB_ClassInfo_HID_Device_t::Config

Config data for the USB class interface within the device. All elements in this section must be set or the interface will fail to enumerate and operate correctly.

uint16_t USB_ClassInfo_HID_Device_t::IdleCount

Report idle period, in milliseconds, set by the host.

uint16_t USB_ClassInfo_HID_Device_t::IdleMSRemaining

Total number of milliseconds remaining before the idle period elapsed - this should be decremented by the user application if non-zero each millisecond.

uint8_t USB_ClassInfo_HID_Device_t::InterfaceNumber

Interface number of the HID interface within the device.

uint16_t USB_ClassInfo_HID_Device_t::PrevFrameNum

Frame number of the previous HID report packet opportunity.

void* USB_ClassInfo_HID_Device_t::PrevReportINBuffer

Pointer to a buffer where the previously created HID input report can be stored by the driver, for comparison purposes to detect report changes that must be sent immediately to the host. This should point to a buffer big enough to hold the largest HID input report sent from the HID interface. If this is set to NULL, it is up to the user to force transfers when needed in the CALLBACK_HID_Device_CreateHIDReport() callback function.

Due to the single buffer, the internal driver can only correctly compare subsequent reports with identical report IDs. In multiple report devices, this buffer should be set to NULL and the decision to send reports made by the user application instead.
uint8_t USB_ClassInfo_HID_Device_t::PrevReportINBufferSize

Size in bytes of the given input report buffer. This is used to create a second buffer of the same size within the driver so that subsequent reports can be compared. If the user app is to determine when reports are to be sent exclusively (i.e. PrevReportINBuffer is NULL) this value must still be set to the size of the largest report the device can issue to the host.

USB_Endpoint_Table_t USB_ClassInfo_HID_Device_t::ReportINEndpoint

Data IN HID report endpoint configuration table.

struct { ... } USB_ClassInfo_HID_Device_t::State

State data for the USB class interface within the device. All elements in this section are reset to their defaults when the interface is enumerated.

bool USB_ClassInfo_HID_Device_t::UsingReportProtocol

Indicates if the HID interface is set to Boot or Report protocol mode.

The documentation for this struct was generated from the following file: