In message <7D4AB72251D4D949AB2732ABEABDA54F130054@PFSG-MX1.ap.p-f.biz> "Chen Xiao Fan" wrote: > http://www.usb.org check out the documents and the forum Eeek.. That's one long specification document... I've been scanning through - "USB in a Nutshell: Making Sense of the USB Standard". I've also been playing around with SnoopyPro (a USB bus-sniffer) - available for free from . It's neat seeing what happens when a device appears, right down to packet level. > http://www.microchip.com/usb download the USB firmware Got them - thanks. I'm looking at the PICDEM FS-USB demoboard code - I've flashed a chip with the bootloader, but the demo code keeps dropping off the USB and then reconnecting. I suspect that's got something to do with the fact I've torn the FS-USB down to the bare minimum of hardware necessary to get USB comms going. In other words, an 18F4550, a 20MHz crystal, a B-type USB connector, two switches, PURs and some decoupling caps. > http://forum.microchip.com check out the USB section Now THAT is useful. Or at least it would be if they didn't delete attachments on what appears to be a weekly cycle... > http://pe.ece.olin.edu/ece/ assmebly and C18 based USB firmware > http://pic18fusb.online.fr/wiki/ 18F USB PIC wiki That last one is a fantastic "get going FAST" type site - my current "USB devboard" is a breadboarded version of the stripped-down PICDEM FS-USB on the 18FUSB Wiki. OK, next steps: 1) Pick apart the 18F USB bootloader, learn how it works, change stuff, see what happens, try not to confuse the Win2k USB stack (too) badly :) 2a) Wire up an LED, write a simple "X sent over USB turns LED on / Y sent over USB turns LED off" firmware app and use LibUSB to test it. 2b) Make the LED example use interrupts instead of polling 3) Try and get some form of primitive GPIB stack up and running 4) Buy a block of VIDs/PIDs from VOTI 5) Debug, tweak and perfect the GPIB stack 6) Release it on an unsuspecting world :P Thanks. -- Phil. | Kitsune: Acorn RiscPC SA202 64M+6G ViewFinder philpem@dsl.pipex.com | Cheetah: Athlon64 3200+ A8VDeluxeV2 512M+100G http://www.philpem.me.uk/ | Tiger: Toshiba SatPro4600 Celeron700 256M+40G ... Pets just die on you, where's the fun in that? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist