Gumstix User Wiki - User contributions [en]

User:Balzi

2009-07-10T05:18:43Z

Balzi: New page: I work for a company in Rural Victoria, Australia. We were using the basix200 for our data-concentrating hub. I first got connected to this wiki after finding the the basix line from gums...

I work for a company in Rural Victoria, Australia.
We were using the basix200 for our data-concentrating hub. I first got connected to this wiki after finding the the basix line from gumstix was being phased out.
I am still trying to find a clean alternative to the basix200. <br>
We bought a verdex-pro XM4 as it suited the same console-st motherboard, so we expected the same IO capabilities. We were wrong - USB client is different.

On top of this, we are struggling to quickly adapt all oru previous work to the OpenEmbedded devel environment. I'm slowly learning bitbake, but I'm an embedded C programmer, and the dynamics of a huge bitbake recipe which calls upon probably 100s of others, are hard to grasp for me.

Talk:USB

2009-07-07T01:17:16Z

Balzi: forgot to sign/date my discussion entry.

This looks like it should just be combined with the article "USB on the 24-Pin Flex Connector" (http://www.gumstix.net/wiki/index.php?title=USB_24_Pin). -jsarao

<br>
re: the small section informing users that USB client support is not available on verdex pro. I'm happy to discuss these changes. My motive for the update was to give a clear indication to people doing the same investigation that I am doing, that GUMSTIX Verdex Pro boards have no Client capabilities and point them to the sources of confirmation I have found.
This section should be updated :
* if I am just plain wrong.
* if the situation changes.
* perhaps to explain:
** why its not available,
** how they can hack to make it available (if possible),
** which other GUMSTIX computer modules have that ability.
--[[User:Balzi|Balzi]] 20:17, 6 July 2009 (CDT)

Talk:USB

2009-07-07T01:16:46Z

Balzi: Starting discussion about lack of USB Client section.

USB

2009-07-06T06:49:50Z

Balzi: Adding in details about USB Client support, which seems to be a common gripe among Verdex owners.

{| 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 [[24pin_connector|24-pin flex ribbon]] connector has '''USB Host port 1''' on it. '''USB Host port 2''' is on the [[60pin_connector|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 ===
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 Capabilites (nabble.com)]
* [http://docwiki.gumstix.org/Setting_up_USBnet#USBNet_.28not.29_on_Verdex USB not on Verdex (docwiki.gumstix.org)]

== Examples ==

[[image:24pin-connector-usb-example.png]]

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]

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