 About Intel Pxa27x-processor And Usb-capabilities |
OESF Forums > Distros, Development, and Model Specific Forums > Model Specific Forums > C1000/3x00 Hardware
 Mar 21 2005, 04:22 PM
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#1
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Group: Members Posts: 23 Joined: 8-December 04 From: Koblenz, Germany Member No.: 5,837  |
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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Mar 22 2005, 01:00 PM
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#2
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 Group: Members Posts: 1,284 Joined: 31-January 04 From: Vancouver, BC -> NYC, NY Member No.: 1,633 |
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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Mar 22 2005, 01:04 PM
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#3
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Group: Members Posts: 23 Joined: 8-December 04 From: Koblenz, Germany Member No.: 5,837 |
Without power supply.
The battery is 3.7 V too. |
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Posts in this topic
ChrisZ About Intel Pxa27x-processor And Usb-capabilities Mar 21 2005, 04:22 PM
barbjfox2000 Chris,
Thanks for illuminating. Since I don't... Mar 22 2005, 09:53 AM omega If you look around, wasn't there something men... Mar 22 2005, 10:16 AM bluedevils It shouldn't surprise you that a desktop HDD... Mar 22 2005, 11:02 AM
ChrisZ QUOTE(bluedevils @ Mar 22 2005, 07:02 PM)It s... Mar 22 2005, 12:33 PM bluedevils My error. I did not realize the 1.8 inch's po... Mar 22 2005, 12:42 PM ChrisZ Errors everywhere:
I've taken my Z and meassu... Mar 22 2005, 12:49 PM |
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