USB

2011-10-06T05:13:12Z

Jordg: /* USB Client */

{| border="1" cellpadding="5" cellspacing="0"
|-
| style="width:100px;background:limegreen;" | USBH_PWR1 || colspan="2" | Over-current fault indicator (input, active low)
|-
| style="background:limegreen;" | USBH_PEN1 || colspan="2" | Power enable USB port (output)
|-
| style="background:limegreen;" | USBH_P1 || rowspan="4" align="center" | USB port || USB D+
|-
| style="background:limegreen;" | USBH_N1 || USB D-
|-
| style="background:tomato;" | V_BATT || USB VBUS
|-
| style="background:grey;" | GND || USB DGND
|}

The [http://www.gumstix.net/Hardware/view/I/O-connectors-cabling/Gumstix-Verdex-Pro-24-pin-flex-connector/112.html 24-pin flex connector]] connector has '''USB Host port 1''' on it. '''USB Host port 2''' is on the [http://www.gumstix.net/Hardware/view/I/O-connectors-cabling/Gumstix-Verdex-Pro-Verdex-Connex-Basix-60-pin-connector/112.html 60-pin Hirose connector].

The pinouts you need for USB Host port 1 are:

* V_BATT (pin 24) - USB power
* USBH_N1 (pin 18) - USB D-
* USBH_P1 (pin 17) - USB D+
* GND (pin 8) - USB Ground

In addition, you need to pull USBH_PWR1 (pin 20) up to 3.3 volts to enable the port (this is a hack, USBH_PEN1 and USBH_PWR1 should be routed to a power switch IC -for example [http://www.ti.com/lit/gpn/tps2041b TPS2041B]- to power the USB port and monitor over-current/short-circuit conditions). You need to provide a stable 3.3 volt supply, which is fairly simple to do by adding a small SOT23 package voltage regulator (like the [http://www.national.com/mpf/LM/LM3480.html LM3480]), with the power input coming from V_BATT (pin 24) and the output going to USBH_PWR1 (pin 20).

USBH_N1 and USBH_P1 (D-/D+) require 15K pull-down resistors each, 10-25 ohm series resistors and 68-75pF capacitors. ESD protection/transient suppression is recommended (example: [http://www.ti.com/lit/gpn/sn65220 SN65220 single port transient suppressor]).

Refer to the PXA270 Design Guide, P. 202 (link on the bottom of this page) for more information.

=== USB Client ===
USBNet is working on the Verdex Pro<BR>
See: [http://old.nabble.com/PXA270-USB-Client-Working!-td25484211.html PXA270-USB-Client-Working (old.nabble.com)]

The following is obsolete:<BR>
For those users attempting to get USB Client capability on their verdex-pro computer, it appears that the right signals are not brought out on any expansion.
I cannot verify this absolutely for myself - but the docomentation appears to agree with my experience. I have been testing with a console-st I/O board.
Here's the details being discussed as recently as January 2009.
* [http://www.nabble.com/USB-Client-Capabilities-%2B-Driver--td21084353.html USB Client Capabilities (nabble.com)]
* [http://docwiki.gumstix.org/Setting_up_USBnet#USBNet_.28not.29_on_Verdex USB not on Verdex (docwiki.gumstix.org)]

== Examples ==

[http://www.gumstix.net/wiki/images/3/39/24pin-connector-usb-example.png 24-pin connector USB example]

USB Host example without ESD and over-current protections (not fully USB-compliant)

== Related ==

[http://pubs.gumstix.com/documents/PXA%20Documentation/PXA270/PXA270%20Design%20Guide%20%5b280001-002%5d.pdf PXA270 Design Guide, P. 202]

[http://www.usb.org/developers/docs/usb_20_092407.zip Universal Serial Bus Revision 2.0 specification]

[ftp://ftp.compaq.com/pub/supportinformation/papers/hcir1_0a.pdf Open HCI—Open Host controller Specification for USB]

[http://www.fairchildsemi.com/an/AN/AN-5052.pdf Implementing the Physical Layer in a USB 2.0 Compliant System, AN-5052, Fairchild Semiconductor]

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[[Category:Literature]]
[[Category:How_to_-_usb]]

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