Re: [Gumstix-users] Overo Tide + Tobi board, Thumbo problems

[Bob C. <bco...@ve...>]

Hi,

Sorry for my earlier rushed reply with just my website address. What the 
photos are showing in that is how to gain console access to the Overo, 
using a host computer connected to the Gumstix over a 
USB-translated-to-serial connection.

Before I start out, let me tell you and everyone else that my 
understanding of USB is weak. I need to order some of Jan Axelson's 
books and do some serious study. So what I say below could be erroneous 
in part or whole.

USB OTG means that you can connect this connector to a powered hub with 
a special on-the-go USB cable, and the port will provide host 
communications to the hub. So the expansion board becomes the USB host. 
Just like your desktop computer is a USB host. You need a special cable 
for this to work and you need a hub that supplies enough current so that 
all the connected devices will have sufficient power from the hub.

I'm not real familiar with the functionality of the "USB host standard 
A" connector. I think with my Gumstix expansion boards, I've always used 
the console and USB OTG connectors and not connected the Standard A.

I have the Thumbo, obviously, and also the Pinto-TH, shown lower down on 
that web page. These two devices can't get console access except as 
documented by Steve Sakoman. The USB connector on the Thumbo is meant to 
supply power to a non-wireless Overo COM. You cannot ssh to the COM 
without networking in some form, so I'm not sure how you expect to ssh 
over USB.

You can ssh into a COM that uses the Tobi board and which is connected 
to a wired network. I have that too, and I'm able to network boot with 
this board thanks to Scott Ellis.

I am not certain of the options in the local.conf file, sorry. I can 
tell you that these options are probably "generic" options and are not 
tailored to what is possible for every specific expansion board. That is 
to say, the contents of the local.conf are probably not hardware 
specific to the Thumbo board, for example. At this point my 
understanding of the file stops...you will have to 'man local.conf' to 
learn more of it.

My advice is for you to start out with the Tobi board because you 
probably have a monitor that can take an HDMI or HDMI-to-DVI connection, 
and you can connect it to the Tobi's HDMI port, thus giving you easy 
video to play with. The networking is also very easy to start on the 
Tobi, just plug in a cable and get an IP address from your DHCP server 
which is probably a router box in your house. You can also run a console 
connection to your host desktop or laptop computer over kermit. Plug a 
hub into the OTG port using an USB "OTG" cable and plug your keyboard 
and mouse into the hub, and presto! You have a small running computer.

Later on, when you feel more confident, solder pin headers to your 
Thumbo and plug it into a breadboard, and get console access using the 
FTDI cable. Tis easy. I have not really used my Thumbo yet, but I have a 
7-segment serial display project (also documented originally by Steve 
Sakoman) that I very much want to do this weekend. I'll photograph and 
post the photos and a discussion of my resulting setup. I've been 
dragging my feet on this project because I know I need updated kernel 
and u-boot images for the Overo.

Using the signals provided by the Thumbo and Pinto-TH is the real reason 
for having these boards. It is very convenient to access the signals on 
a breadboard.

I hope this helps a bit.

Bob Cochran



On 6/30/11 6:26 PM, justynnuff wrote:
> Okay, I know I'm back pedalling but now I have even more questions.
>
> In the local.conf file you can change the mode from "host", "peripheral",
> and "otg."
>
> According to the Tobi's product description, it has
> a "USB OTG mini-AB" and
> a "USB host standard A" connections.  So what am I changing by changing the
> option in the local.conf file?  Clearly not those ports right?
>
> Then the Thumbo says it has
> a "USB standard A plug with OTG signals (wired as a device)**"  As in it has
> no console access..  But the Tobi's OTG port has "no console access", I can
> still ssh to it, which is ultimately what I want to do to that giant USB on
> the front of the Thumbo!  I'm not worried about console access.
>
> I guess I'm just a little confused on the definitions of "host" "peripheral"
> and "OTG", "wired as a 'device'", "OTG signals" etc.
>
>
>
> Bob Cochran wrote:
>> http://mysite.verizon.net/bcochran13/
>>
>> My grateful thanks to Steve Sakoman for the original blog post that got
>> me started.
>>
>> Bob Cochran
>>
>>