MM7150

DS00001888B-page 8

 2015 - 2016 Microchip Technology Inc.

3.0

MM7150 HID FUNCTIONS

The hierarchy of descriptors used in the HID protocol is as follows:

The following sections described the descriptors required for communicating with the MM7150:

3.1

HID Descriptor

3.2

Report Descriptors

Report descriptors are composed of pieces of information. Each piece of information is called an Item.

The HID class driver contains a parser used to analyze items found in the Report descriptor. The parser extracts infor-

mation from the descriptor in a linear fashion.

The parser collects the state of each known item as it walks through the descriptor, and stores them in an item state

table. The item state table contains the state of individual items. From the parser's point of view, a HID class device looks

like the following.

TABLE 3-1:

Field

Description

Size

Value

wHIDDescLength

Length of HID Descriptor

UINT 16

0x001E

bcdVersion

Version compliance. Compliant with Version 1.00

UINT 16

0x0100

wReportDescLength

Report Descriptor Length (3213 bytes)

UINT 16

0x0C8D

wReportDescRegister

Identifier to read Report Descriptor

UINT 16

0x0002

wInputRegister

Identifier to read Input Report

UINT 16

0x0003

wMaxInputLength

Input Report is 13 Bytes + 2 Bytes length field

UINT 16

0x000D

wOutputRegistert

Identifier to read Output Report

UINT 16

0x0000

wMaxOutputLength

No Output Report

UINT 16

0x0000

wCommandRegister

Identifier for Command Register

UINT 16

0x0005

wDataRegister

Identifier for Data Register

UINT 16

0x0006

wVendorID

Vendor ID

UINT 16

0x04D8

wProductID

Product ID

UINT 16

0x0F01

wVersionID

Version

UINT 16

0x7150

RESERVED

Reserved

UINT 32

0x0