USB (was Re: OVERRIDING MIDI pt.II)

[Jonathan Mayer]

>okay, i admit it! i'm a circuit-burning newbie... what's USB?

it's not a newbie question .. usb is the newbie here.

glossy overview:

USB is the universal serial bus ... cooked up by a big consortium led by
intel, it's meant to be "out of the box plug and play."  The idea is to
have a single serial data bus that everything plugs into, that
auto-configures every time something is added or removed from the bus.

The idea is that rather than having many (costly) incompatible ports
dedicated to different functions, all of these devices can all share the
same USB port:  keyboards, modems, printers, ISDN, mice, tablets,
networks, etc.  etc.

The idea is that, if you want to install a new modem, you just plug in the
modem to any spare USB port, and you're done.

details:

all devices on a usb arbitrate for shares of a 12Mb/s serial data stream. 
The usb connector supplies power and ground (no more wall-warts).  Some
usb devices act as 'hubs' for more usb devices, letting you daisy-chain
your network of usb devices in a tree-like configuration.  A maximum of
126 devices can be hooked up like this. 

rant:

Wouldn't it be neat to have a recording studio where everything in the
studio interconnects on usb?  Heck, imagine a studio where everything
receives control data on the USB, then broadcasts back it's digital
samples on the same USB, to be digitally mixed on a separate
(usb-controlled) digital mixing deck.  One cable for everything.  Swap in
and out components without having to reconfigure anything... (not that I
have any studio experience or anything).  (actually, that pipe-dream
pushes up against the usb bandwidth limit ... only 5 devices can transmit
24-bit samples at 96ksamps over a usb at once .. darn!). 

Many new motherboards currently have usb on-board (all boards that use an
intel VX or HX chipset have USB support).  I predict in a year or so all
new computers will have usb ports.

What I'm trying to do is build a simple USB application board for
homebrewers to use to control things like synths, robots, tester
equipment, the world, etc. :)

jm.

_____________________________________________________________________________
Jonathan Mayer         http://www.crystal.com       jmayer at crystal.cirrus.com