Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Usb Connection With The Hid Class Driver

2,001 views

Published on

USB development

Published in: Technology
  • Be the first to comment

  • Be the first to like this

Usb Connection With The Hid Class Driver

  1. 1. USB Communication/Configuration Overview How does communication between a USB device and a PC work? How does a USB device initiate contact with a PC?
  2. 2. How does communication between a USB device and a PC work? Logical Communication Flow Endpoint 1 Endpoint 2 Endpoint N Endpoints Have 4 Transfer Types: Control Transfer – For sending commands Interrupt Transfer – Host must poll this EP Isochronous Transfer – Time sensitive Info Bulk Transfer – For large data bursts Buffer 1 Buffer 2 Buffer N Data is sent to memory buffers which will be processed by the software application Interface 1 Software Application Interfaces : grouping of the endpoints into a functional group performing a single feature of the device. For example: Keyboard,Mouse,Camera,Scanner,DVD drive Operating System
  3. 3. How does communication between a USB device and a PC work? Renesas H8S /2215 Device c PC OS Firmware Hardware Firmware Hardware Firmware Firmware Interface Description Grouping of endpoints performing a single feature of the device Relationship Collection of Endpoints Various transfer types: Control,Interrupt, Isochronous,Bulk Data Transfer Per Endpoint Serial Interface Engine USB Bus Interface Physical/Signal/Packet Connectivity Data USB Driver Software Application Interprets data based on Interfaces Buffered Data USB Bus Interface Serial Interface Engine Physical/Signal/Packet Connectivity USB Cable Data Host Controller Driver Device’s configuration, status, and control information. Endpoint 0: Control Pipe Manages System Devices . Data USB System Software Host Controller UHCI OHCI EHCI Data
  4. 4. How does a USB device initiate contact with a PC? Configuration Descriptor How the Device is setup Device Address Device Descriptor Represents the device 1 USB System Software Endpoint 0 Control Pipe Device’s configuration, status, and control information. Wait 100ms for USB Stabilization 2 3 PC gives Device an Address 4 PC requests Device Descriptor 5 PC requests Configuration Descriptor 6 Windows asks for driver for the device. Driver is then located and installed. 7
  5. 5. How does a USB device initiate contact with a PC? USB System Software Endpoint 0 1 Wait 100ms for USB Stabilization 2 This descriptor contains the Interface and Endpoint descriptor 5 Configuration Descriptor How the Device is setup PC gives Device an Address Device Address 4 3 Device Descriptor Represents the device PC requests Device Descriptor 6 Windows asks for driver for the device. Driver is then located and installed. 7

×