1. Serial Interfaces

2. Bit serial bus New generation of busses Uses bit-serial, differential drive technology Uses on-line device drivers (Hot-plug technology) Automatically detects plugged in devices and configures the controlling software Two main tech : USB and Firewire

3. USB : Universal Serial Bus 12 Mb/s serial bus Hot-plug tech (plug & play) Supports up to 127 external devices Provides power USB 2.0 : 480 Mb/s serial bus vdd,gnd D+, D-

4. Bus topology Tiered star structure, up to tier 6

5. USB devices HUB Serve to USB connectivity Can detect attach and detach Hub Controller + Hub repeater Functions USB device that is able to transmit or receive data

6. USB host Client Describes all the software entities that are responsible for USB devices USB System Translation between the client data and USB transaction on the interconnect Managing USB resources(bandwidth, power …) USB Bus interface Handles interactions for the electrical protocol layer

7. USB data flow

8. Bus Protocol Host controller initiates data transfer by generating ‘token packet’ Data transferred Handshake packet for completion handshake data transfer token Type of transaction Direction of trans. USBdevice address

9. Attach and Remove of USB Devices Host Hub port upstream port device Enable port allocate USB address indicatordisable Remove indicator

10. Data flow types Control transfers configure device at attach time Bulk data transfers generate or consume large data. error detection and retries used ex) file Xfer Interrupt data transfers Small, limited latency transfer ex) event notification, echo from device Isochronous data transfers Continuous and irregular data. ex) voice

11. Firewire 400 Mbps ( 3200Mbps for 1394b ) Plug & play Support 63 devices Provides power Comparison to USB USB is host-based(must be connected to computer), Firewire is peer to peer (two devices can be connected directly)

12. Website http://www.usb.org http://www.apple.com/firewire