SDAA062 September   2025 TMS320F28P559SJ-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Intelligent Cabin and IVI System
    2. 1.2 USB Interface Application in IVI
    3. 1.3 TMS320F28P55x Introduction
  5. 2USB Composite Device Enumeration and Data Report
    1. 2.1 USB Composite Device Enumeration
      1. 2.1.1 Descriptor Structure
      2. 2.1.2 Descriptor Types
        1. 2.1.2.1 Device Descriptor
        2. 2.1.2.2 Configuration Descriptor
        3. 2.1.2.3 Interface Descriptor
        4. 2.1.2.4 Endpoint Descriptor
        5. 2.1.2.5 String Descriptor
    2. 2.2 USB Composite Device HID Data Report
      1. 2.2.1 Data Report Item
      2. 2.2.2 HID Report Descriptor Structure
        1. 2.2.2.1 Main Item
        2. 2.2.2.2 Global Item
        3. 2.2.2.3 Local Item
    3. 2.3 Example of Building a HID Report Descriptor
  6. 3Software Realization
    1. 3.1 APIs for USB Composite Device Initialization
      1. 3.1.1 USBStackModeSet
      2. 3.1.2 USBDCDCCompositeInit
      3. 3.1.3 USBDHIDCustomCompositeInit
      4. 3.1.4 USBDCompositeInit
    2. 3.2 APIs for USB Composite Device CDC Data Report
      1. 3.2.1 USBBufferSpaceAvailable
      2. 3.2.2 USBBufferWrite
      3. 3.2.3 USBBufferRead
      4. 3.2.4 USBDCDCTxHandler
      5. 3.2.5 USBDCDCRxHandler
    3. 3.3 APIs for USB Composite Device HID Data Report
      1. 3.3.1 USBDHIDCustomTouchEvent
      2. 3.3.2 USBDHIDCustomReportKey
    4. 3.4 APIs for USB Composite Device Simulation
      1. 3.4.1 MultTouchSimHandler
      2. 3.4.2 KeySimHandler
    5. 3.5 APIs for USB Device Operate States Query
      1. 3.5.1 USBDCDCControlHandler
      2. 3.5.2 CustomHandler
  7. 4System Test
    1. 4.1 Test Setup
    2. 4.2 USB SCI CDC Device Function Test
    3. 4.3 USB Touch Screen HID Device Function Test
    4. 4.4 USB Button HID Device Function Test
  8. 5Summary
  9. 6References
  10. 7Appendix

2.2.1 Data Report Item

The HID data reporting uses the item as the basic message element, and changes the item headers to identify the different HID devices report contents. The HID report descriptor must be specified once the interface descriptor defines a HID interface. The item format is shown in Figure 2-2. Bits 23-8 represent the data to be transmitted. Bits 7-0 are the item header. bSize specifies the data length of the item in bytes. bType specifies the item types. The definition details are shown in the following text. bTag specifies the item types which is described in Configuration Descriptor. The complete definition of bTag can be found on the USB-IF official website.

Data Report Items Structure Figure 2-2 Data Report Items Structure

bSize = 0 – No available data

bSize = 1 – 1-byte available data

bSize = 2 – 2-bytes available data

bSize = 3 – 4-bytes available data

bType = 0 – Main item

bType = 1 – Global item

bType = 2 – Local item