Alan Stern said: > On Wed, 4 Jun 2003, David Brownell wrote: > >> Have a look at the EZ-USB doc to see the details, which >> I fudged a bit. It initiates re-enumeration, I forget >> exactly how, and clearly can't lose power since that'd >> mean the firmware got lost. (It's all detailed in one >> of the earlier chapters in the technical reference manual, >> which is a big PDF doc you can download from Cypress.)
So you don't have to go digging, the EZ-USB Tech Reference Manual is here: http://www.cypress.com/cfuploads/support/developer_kits/ez-usb_trm.pdf The EZ-USB FX TRM is a little harder to find: http://www.cypress.com/cfuploads/support/developer_kits/FF8EFAB3-2E98-4448-92418D0EA786766D_doc_1.pdf but the end effect seen by the host should be the same. > I'll check it out at some point. But it still sounds strange. For > the time being, let's try to ignore it. It sounds strange to me as well :-) Here's how I understand it: The EZ-USB chip does not really "reset", it just sends a disconnect signal (by temporarily disconnecting power to the 1.5K pull-up resistor on D+ that signifies that a full-speed device is attached). This is basically done by setting a few bits, busy-waiting for a bit, and resetting the bits. David is right in saying that the chip does not lose power, and in fact, the chip does not have to reset its microcontroller core, either-- it can just respond to the control messages it gets after the host sees the "new" device reattaching to the bus. See page ~81 in the non-FX TRM for details. HTH, -- Charles Lepple <[EMAIL PROTECTED]> http://www.ghz.cc/charles/ ------------------------------------------------------- This SF.net email is sponsored by: Etnus, makers of TotalView, The best thread debugger on the planet. Designed with thread debugging features you've never dreamed of, try TotalView 6 free at www.etnus.com. _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
