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> About Intel Pxa27x-processor And Usb-capabilities
ChrisZ
post Mar 21 2005, 04:22 PM
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Hi!

I've just read in the Intel PXA27x-specification. And there are some interesting things about the USB-capabilities of the processor:

USB-client: USB 1.1 with max. 12 Mbps

USB-host: USB 1.1 with max. 12 Mbps. The host provides 3.3 V to clients but the normally necessary 5 V for HDD or something "bus-powered" are not provided. And, the 3.3 V output is combined with a max. current of 25 mA and therefore 82.5 mW. That's much too less for a harddisk. According to Toshiba, Hitachi, Seagate and Fujitsu, current 1.8 inch harddisks need at least 1.2 W for spin-up.

Intel (see ftp://download.intel.com/design/pca/appli...als/2800002.pdf and ftp://download.intel.com/design/pca/appli.../28000502.pdf):
QUOTE
The +5 V VBUS source from USB host controller, which must be available for bus-powered peripherals, must be supplied from an external source, but it is not part of the PXA27x processor silicon.


I don't think Sharp added some additional USB functions which were not provided by the PXA270.

It's too bad, I really thought I could use an external HDD without power supply.
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bluedevils
post Mar 22 2005, 01:00 PM
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Did you measure that with the Z plugged in or when it is using battery power? I ask this because external power is 5v, but my 760's and 6000's batteries are 3.7v (is the 3000 different?).
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ChrisZ
post Mar 22 2005, 01:04 PM
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Without power supply.

The battery is 3.7 V too.
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