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serial for pogo pink?

Posted by sdmann 
serial for pogo pink?
November 08, 2010 03:53PM
Hi All,

First, thanks Jeff for all the great work and all the responses here. I would not have gotten this far this fast without it!

So, now for something really simple.

I've constructed a null modem cable. It has a DB-9 connector at one end and a USB-A connector at the other. I know this cable works, because I've tested it between two Linux systems - setting up one with *getty and the other using variously minicom and cu. It works at speeds from 9600 to 115200.

I have a pogo pink with Jeff's latest uboot image. It boots fine, but won't boot from the USB drive...I think that the drive/controller may be too slow. But that's ok, I have this fabulous serial cable, so I should be able to see what's going on.

OK. Now, I connect the cable to the pogo pink (with or without the USB drive attached - behavior is the same except with the drive attached it takes longer to boot). On the linux system, I either run cu or minicom on /dev/ttyS0. Then I reboot the pink pogo. All I get are a few non-printable characters. In the past, when I've seen this, it usually ends up being a baud rate or flow control issue...but I've played with all of that and nothing seems to work. I get these non-printable characters when I use the configuration described at http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.1. Basically, it is 115200, 8N1, and no hardware flow control.

Any ideas? I suppose I could just try the nc stuff, but I would really like to get this working - it seems that I must be missing something really simple. Does it matter which USB port on the pink I use?

Re: serial for pogo pink?
November 08, 2010 04:51PM
U-Boot doesn't know how to use a USB-serial adapter, only a true serial port. I don't have a Pink Pogoplug, but if it's sufficiently like the DockStar then that means finding the on-board connector and attaching a modified USB-to-3.3V cable (like the Nokia CA-42 clones that you can find cheaply on eBay) -- not a regular one like you describe (because that will probably use 5V and fry the onboard serial circuit).

There's a long thread about which cables and connectors people have used on the plugapps.com hardware forum.

Now, having said all that, you probably can configure Linux to use the USB-serial adapter as its console, so you can see the early boot messages that way, but that's not your problem. If you don't want to mess with connecting a cable, then netconsole is your best alternative.
Re: serial for pogo pink?
November 08, 2010 05:06PM
Well, that explains a lot! Thanks!

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