1. Universal Serial Bus Jordan Weichel Jacob Lucero Tony Lucchesi 1

2. Outline http://www.brandsoftheworld.com/search?query_id=3996676&page=1&mtype=&brand_id=22618 Overview Design Interface Power 2

3. History USB 1.0 o Full Speed 12 Mbits/s (1.5 MB/s) o Low Speed 1.5 Mbits/s (0.2 MB/s) o 1996 o USB 1.1 (1998) USB 2.0 o High Speed 480 Mbits/s (60 MB/s) o 2000 USB 3.0 o SuperSpeed 5.0 Gbits/s (625 MB/s) o 2008 3 http://www.legitreviews.com/article/1150/1/

4. USB in Embedded Systems 4 Self powered Fast communication Most reliable way to talk to computers

5. USB Wires and Ports http://commons.wikimedia.org/wiki/File:Types-usb_new.svg http://i.imgur.com/XwIqQ.jpg 5

6. High-level Design http://www.l-com.com/images/usb-tutorial-tier-topology.gif 6

7. Endpoints http://www.mightyape.co.nz/product/Canyon-Full-HD-1080P-Webcam-with-Mic/20977976/images/14450845/ Endpoints o 32 per device o (Device_addr, endpoint_num) 7

8. Pipes Message pipes o Control Short and simple for commands and queries Stream pipes o Interrupt Small bounded latency for quick transfers o Bulk Large transfers use remaining bandwidth o Isochronous Guaranteed data rate 8

9. Process http://upload.wikimedia.org/wikipedia/commons/1/1b/USB_pipes_and_endpoints_%28en%29.svg Picture from beyster 1695 p28 Enumeration o Host assigns each device an address o Host acquires stream transfer types o Post enumeration 9

10. USB Protocols 1.Token Packet o Initiatiates communication 2.Data Packet o Contains information / payload 3.Status Packet o Acknowledges transactions o Reports errors 10

11. Transaction 11

12. USB to UART Example 12 USB VCC(+5v) Data+ Data- USB GND Data Out Data In https://www.sparkfun.com/products/650

13. Power Pins http://1.bp.blogspot.com/-6nvzXThVlNU/T9pnBRiSr-I/AAAAAAAAB0o/MFVOHHENVbk/s1600/pin-out-usb3_usb2A.jpg 13

14. Vocabulary 100 mA = 1 unit load V bus = V CC o 500 mA max draw from V bus per device o 5 V goal Source o Powered vs. unpowered 14

15. Power Overview http://mac-ave.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/3/1/31joqfxn1yl._sl500_aa300_.jpg 1. Low-power 2. High-power 3. Self-power 15

16. Low-Power Functions Max draw o 1 unit load (100 mA) Power comes exclusively from V bus Voltage o 4.40 V min o 5.25 V max 16

17. High-Powered Functions Max draw o 5 unit loads (500 mA) Power comes exclusively from V bus Voltage o 4.40 V min o 5.25 V max 17

18. Self-Powered Functions 1 unit load from V bus Rest of the power from external source o Requires safety catch to never draw more than 1 unit load from V bus 18

19. Power Hiccups Suspended devices o Draw no more than 500 µA V bus unstable o Devices are plugged / unplugged Transient voltage dips as low as 4.1 V o Need to design device to handle situation 19

20. Pros and Cons Universal transfer protocol Increased reliability and speed of data transfers Pre-implemented drivers Many devices per host Dedicated hardware Complex debugging http://2.bp.blogspot.com/-RSVGM9fJSBQ/Tk-yHnrC7BI/AAAAAAAAAfU/9by6cOS5U1o/s1600/Parallel-Port.jpg 20

21. Questions? 21

22. References http://www.pcworld.com/article/156494/superspeed_usb.html http://computer.howstuffworks.com/usb3.htm http://www.beyondlogic.org/usbnutshell/usb2.shtml http://www.l-com.com/content/USB-Tutorial.html http://www.wisegeek.org/what-are-the-advantages-of-usb-30.htm http://uk.farnell.com/images/en/ede/pdf/usb_dev_mistake.pdf http://www.usb.org/home http://www.smxrtos.com/articles/usb_art/waysusb.htm https://www.sparkfun.com/datasheets/IC/FT232R_v104.pdf 22