| ??? 01/24/06 14:24 Read: times |
#108177 - USB Configuration Responding to: ???'s previous message |
For a charger using USB VBUS, USB Configuration is the first check point to allocate as much current as possible.
USB Configuration "Is only one configuration descriptor supported?" http://www.usb.org/phpbb/viewtopic.php?t=7777 Guido Koerber said:
Windows just looks at the first configuration descriptor and decides wether or not to configure the device. So if you have two configurations, the first claiming 500mA the second 100mA then your device will get configured only if there is sufficient current for the 500mA available.
We recently developed a controller that allows power sourcing off the USB (IO-Warrior24PV). Our solution is that we reset the device if it does not get configured and then we reverse the position of the descriptors. That works for Windows since it does not configure the device if there is not enough current available. Re-enumeration "Windows doesn't re-enumerate Device after device re-starts" http://www.usb.org/phpbb/viewtopic.php?t=7642 if you want to emulate disconnect/re-connect on the device side, enable/disable the pull-up resister of D+ or D-. Disabling bus pull-up resistor is recognized as disconnection by hub. Enabling it means re-connection. As for timing, please see USB 2.0 Specification 7.1.7.3 Connect and Disconnect Signaling (p149) Cypress EZ-USB: DISCON/DISCOE(USBCS) Cypress EZ-USB FX1/FX2: DISCON(USBCS.3) Microchip PIC16C745/765: - external Microchip PIC18F245x/445x: UPUEN(UCFG.4) SiLabs 'F32x: PREN(USB0XCN.7) Philips ISP1161A DcMode(SOFTCT) Philips PDIUSBD12 SetMode SoftConnect (bit 4) Atmel DETACH(USBCON.4) "Software Replug" http://www.cygnal.org/ubb/Forum9/HTML/000504.html Tsuneo |
| Topic | Author | Date |
| More on 8051 + USB (low vs full speed) | 01/01/70 00:00 | |
| SiLabs F32x | 01/01/70 00:00 | |
| re deviates | 01/01/70 00:00 | |
| Atmel AT89C5131 or 5132 | 01/01/70 00:00 | |
| uPSD 3434A | 01/01/70 00:00 | |
| Microchip 18F4550 | 01/01/70 00:00 | |
| just on the off chance | 01/01/70 00:00 | |
confidence is low | 01/01/70 00:00 | |
| have you checked Cypress | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| low vs full speed | 01/01/70 00:00 | |
| usb charging circuit | 01/01/70 00:00 | |
| USB 2.0 spec | 01/01/70 00:00 | |
| USB Configuration | 01/01/70 00:00 |