USB host for web camera connection High Speed Digital Systems Lab USB host for web camera connection Final presentation – Part A Presenters: Alexander Shapiro Sergey Alexandrov Supervisor: Mike Sumszyk

Agenda Part B project objectives Demo Project objectives. System architecture. Project flow. USB basics. ISP 1362. Isochronous transfer. YUV video. Part B project objectives Demo

Project Objectives Implementation of SOPC interface for USB webcam. Learn and implement USB host protocol. Learn and implement webcam protocol. Learn SOPC Development tools. Understand NIOS II architecture. Building NIOS II softcore system. Receive picture from the webcam. Convert YUV to RGB and display in Matlab

Development Environment Altera DE2 board Provides USB support for host and device application. VGA output (up to1600 x 1200 at 100-Hz refresh rate). Cyclone II FPGA Programmable chip to implement any design. Programming tools: Quartus II, Nios II IDE, SOPC Builder Debug tools: Hardware and software USB analyzer.

System Architecture Input Output USB Philips ISP1362 controller. Transfer rate: 12 Mb/s. Output Change the System architecture diagram VGA DAC (10-bit triple DACs). Up to 1600x1200 at 100-Hz.

Logic Flow diagram

Project Flow

Learn stage Working environment USB and ISP1362 documentation SOPC builder NIOS II USB and ISP1362 documentation Take mouse demo as basis for USB system.

Host implementation Initialize connection and open communication port. Determine the kind of device. Request configuration descriptor. Learn basic device capabilities.

Webcam interface implementation Probe and commit sequence. Negotiation between Host and Video streaming interface. Consists of Host`s requests with supported streaming parameters (bit rate, resolution) and Client`s confirmation/denial Select video interface. Device is configured and ready to work.

Webcam interface implementation Probe & Commit flow Host and device negotiate acceptable configuration. It may take several iterations to “agree”

Mid-project milestone Working webcam interface on NIOS II system Initialization Configuration Bulk data transfer No isochronous traffic support

ISO transfer over Philips ISP1362 Isochronous transfer is the most challenging aspect of the USB protocol. Main issue – absence of code examples. Almost no help could be obtained from forums and documentation. No guidelines for implementation in Programming Guide. Was implemented from scratch. USB analyzer was irreplaceable in understanding and debugging.

ISO transfer over USB Host periodically sends ISO IN requests. Device responds with ISO packets. Each packet consists of payload and data. Header holds error checks and End Of Frame indicators. DATA is video stream in YUV2

Isochronous transfer buffering Challenge: Data to be delivered and processed each mSec. CPU on embedded system cannot handle data each mSec. Solution: ISP 1362 supports double buffering for ISO transfer One buffer is proceeded while the second is filled. 1024 bytes in each buffer. Toggle rate is configurable.

Debug tools: USB analyzer USB HW analyzer is irreplaceable in debug. Shows real traffic between host and device Triggers on defined events Clear log of USB packets Showed what packets Windows sends to USB device. Software analyzer can show only driver level packets. Helped find source of bugs. Made it possible to ensure that host/device behaves according to our expectation.

Decode YUY2 video format 2 RGB pixels are defined in each macropixel (four bytes). They share U and V components. Natural bitrate is 2 bytes/pixel Demands efficient real-time decoder to RGB

Part B Project Objectives USB 1.1 Video implementation. Integrate VGA controller. Implement real-time video streaming USB 2 support. Migration to DE-3 environment. Code optimization. DMA Hardware YUV to RGB decoder USB 2 Video streaming to monitor

Demo

References Philips Embedded Programming guide Philips ISP 1362 Data Sheet USB 2.0 Specification USB Video Class Specification USB Complete by Jan Axelson Google

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