Universal Serial Bus Information

Intro.

• Upto 127 devices on one port.
• USB supplies power to the peripherals, reducing the need for wall warts, power bricks and power stealing from the keyboard connector
• Full speed devices communicate with the PC at 12Mbps. Mice and keyboards etc. can communicate at a lower 1.5Mbps rate to reduce cost.
• Hot Pluggable.
• PlugNPlay - The PC recognises each device that is plugged in and loads the appropiate driver. If it's a new device for which it has no driver, and doesn't run with a generic driver, it prompts for a driver to be loaded.
• No confusing cabling - no null modem cables, handshaking lines to mess with etc.
• Supports 4 different data transfer types:- Isochronous, Control, Interrupt, Bulk

OS support

Win 98 has good support, and is stable (well.. for me it doesn't crash more than once a week! - when a USB peripheral does crash, just unplug it then plug it back in, to reinitialise it) - All the manufacturers that had big stocks of USB peripherals ready to launch on the back of Win 98 launch were a bit upset by the low key release of 98.

The Apple iMac took the bold step of doing away with serial and printer ports and ONLY having USB ports - It's helping to kick-start sales of USB peripherals. The Apple G3 also has USB.

Microsoft's spec's for Auto PCs include USB ports as highly recommended and WinCE 2.1 includes USB support (Host only). NT4 doesn't have any support, but NT5 (Win2000 or whatever it gets called!) will have.

For those with anti-windows tendancies, Linux has USB support - see here for more info.
FreeBSD is also believed to have support. (Thanks to Matt for this info.)

The Downside

EITHER need to conform to a generic USB driver class, such as Human Input Device class, Mass storage class, etc. (there isn't many classes as yet and there isn't a PIC / AVR Microcontroller programmer device class as yet for instance)

OR need to write a WDM driver for yourself - not easy, and as this page only covers USB hardware, you'll have to look elsewhere for guidence. (Sorry - You have been warned thou.) See here or see the 98 DDK for example driver code.

Links

USB Peripheral chips

Microcontrollers with FULL SPEED USB interfaces:-
Manufactr	Part Number	Core / Supply V	Data Modes	Endpoints	Package	Other Info / Comments
Anchorchips	AN21XX AN23XX	Enhanced 8051 3.3V,60mA	Bulk, Int, Ctrl, (Iso - some)	upto 31	44 / 80 PQFP (3mm thk)	PPL - only 12MHZ xtal required Firmware downloadable from PC I've only just found these
Cypress	CY7C64XXX & others	Harvard arch. 4.0 - 5.5V	Bulk, Int, Ctrl	upto 5	SOIC28 / DIP28 / SSOP48	PPL - only 6MHZ xtal required Very good/cheap starter kit
Mitsubishi	M37640EX	??? 5.0V	Bulk, Int, Ctrl, Iso	5	80 pin	24MHz xtal
ScanLogic	SL11R	RISC ??? 5.0V	?	?	?	I haven't got the data sheet on me tonight!
Siemens	C541U	C500 based 4.25 - 5.5V	??	5	PLCC44	12MHz xtal NOTE full or slow speed!!!
STMicroelectronics (formerly SGS-Thomson)	ST72671	ST72	?	?	SDIP56/TQFP64	I'm still waiting for the data sheet to download - It's only been 20 days now :-)
SMSC	USB97C100	8051 5.0V	Bulk, Int, Ctrl, Iso	upto 31	128 pin QFP	PPL - only 24MHZ xtal required Firmware downloadable from PC Only seen advanced datasheet

Microcontrollers with SLOW SPEED USB interfaces:- (see also the Siemens chip above)
Manufactr	Part Number	Core / Supply V	Data Modes	Endpoints	Package	Other Info / Comments
Cypress	CY????	Harvard arch. 4.0-5.5V	Int, Ctrl	?	?
Mitsubishi	M37532	????? 4.1-5.5V	Int, Ctrl	?	36 pin 0.8mm SOP 42 pin shrink ceramic
Zilog	Z8E520/C520	Z8plus 4.0-6.0V,6mA	Int, Ctrl	2	20SOIC/PDIP

FULL SPEED USB interface chips:-
Manufactr	Part Number	Interface / Supply V	Data Modes	Endpoints	Package	Other Info / Comments
National Semi	USBN9602	8bit parallel or Microwire 4.0-6.0V	???	7	28 pin SOIC	48MHz xtal / Osc required
Netchip	NET2890 also NET2888	8bit parallel 3.3 - 5.5V	Bulk, Int, Ctrl, Iso	5	48 QFP	48MHz xtal / osc required
Philips	PDIUSBD12	8bit parallel 4.0-5.5V	Bulk, Int, Ctrl, Iso	5	DIP28/SO28/TSSOP28	PPL - only 6MHZ xtal required built-in activity indicator
ScanLogic	SL11	?? 5.0V	?	?	?	I haven't got the data sheet on me tonight!
Thesys	TH6501	SPI bus 4.4-5.25V	Bulk, Int, Ctrl	3	16pin SOP	48MHz xtal / osc required

SLOW SPEED USB interface chips:-
Manufactr	Part Number	Interface / Supply V	Data Modes	Endpoints	Package	Other Info / Comments
Thesys	TH6503	SPI bus 4.4-5.25V	Int, Ctrl	3	16pin SOP	6MHz xtal

USB Hub and Combined USB Hub / Peripheral chips

Projects

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Steve Lawther

Last Updated by Steve Lawther on Thursday, 14 January, 1999 at 10:37 PM.