OESF Portables Forum

Model Specific Forums => Sharp Zaurus => Zaurus - Hardware discussion => Topic started by: Varti on June 12, 2017, 09:41:01 am

Title: USB/serial cable for debugging?
Post by: Varti on June 12, 2017, 09:41:01 am
Hi,

I'd like to find a cable for serial debugging for my Akita, to be connected on the user port on the rear. There are some different user port cables around, most of them are USB ones, but I don't know which ones can be used for serial debugging (I'm thinking especially for kexecboot debugging). The only one that I have been told to work is the CE-170TS, which is very difficult to find:

http://www.penguin.cz/~utx/hardware/Sharp_CE-170TS/ (http://www.penguin.cz/~utx/hardware/Sharp_CE-170TS/)

I have never been able to find one on the japanese Auction site, while many other cables are usually sold there:

CE-175TU: https://buyee.jp/item/yahoo/auction/j403797862 (https://buyee.jp/item/yahoo/auction/j403797862)
CE-UC1: https://buyee.jp/item/yahoo/auction/f214752315 (https://buyee.jp/item/yahoo/auction/f214752315)

Does anybody know if those can be used as well, or if they are only used for syncing, and if they are compatible with an Akita?

Varti
Title: USB/serial cable for debugging?
Post by: HoloVector on June 15, 2017, 12:10:22 pm
Quote from: Varti
Hi,

I'd like to find a cable for serial debugging for my Akita, to be connected on the user port on the rear. They are some different user port cables around, most of them are USB ones, but I don't know which ones can be used for serial debugging (I'm thinking especially for kexecboot debugging). The only one that I have been told to work is the CE-170TS, which is very difficult to find:

http://www.penguin.cz/~utx/hardware/Sharp_CE-170TS/ (http://www.penguin.cz/~utx/hardware/Sharp_CE-170TS/)

I have never been able to find one on the japanese Auction site, while many other cables are usually sold there:

CE-175TU: https://buyee.jp/item/yahoo/auction/j403797862 (https://buyee.jp/item/yahoo/auction/j403797862)
CE-UC1: https://buyee.jp/item/yahoo/auction/f214752315 (https://buyee.jp/item/yahoo/auction/f214752315)

Does anybody know if those can be used as well, or if they are only used for syncing, and if they are compatible with an Akita?

Varti
The Akita's serial port doesn't provide enough power to run those USB cables. Trisoft confirmed that as well. Only the CE-170TS can work with the 3.3v that it puts out.  There is one on eBay at the moment (http://m.ebay.ca/itm/Sharp-Serial-Cable-for-Zaurus-SL-5500-6000L-RS-232C-Port-4-9-Ft-CE-170TS-/162526376510?hash=item25d753b23e%3Ag%3A4VkAAOSw42JZJEa4&_trkparms=pageci%253Ac7e92281-51e3-11e7-92d5-74dbd1804dac%257Cparentrq%253Aac7c389715c0a9c4dff6ddf6fffef7bc%257Ciid%253A2).  It has a make offer so you be able to get it for cheaper than that.
Title: USB/serial cable for debugging?
Post by: Varti on June 16, 2017, 02:41:06 pm
Thanks for the info. Does this limited support of cables apply to Akitas only, or to the SL-C3xxx as well? Thanks also for the Ebay link, 99 pounds (=113 euros!) is way too much for such a cable, that's the price of a full Zaurus... I have made him an offer of 15 euros, I don't think he'll accept it though...

Varti
Title: USB/serial cable for debugging?
Post by: HoloVector on June 16, 2017, 03:45:13 pm
Yes, this applies to the entire Cxxxx series.  During the system board redesign, the 5V lines used for the serial port on the Cxxx were redirected to the USB host port instead thus leaving the Cxxxx series serial port with only 3.3V lines and it being downgraded to a diagnostic port only.  

I seem to remember that the fellow who added internal wifi and Bluetooth to his Akita used the second cf port 5V power traces to run these added devices and he theorized that they could be used to up the power to the diagnostic port.
Title: USB/serial cable for debugging?
Post by: Dromede on October 17, 2017, 03:57:43 pm
I most probably have one lying in a drawer somewhere, PM or email me.
Title: USB/serial cable for debugging?
Post by: Varti on October 18, 2017, 04:58:42 am
Quote from: Dromede
I most probably have one lying in a drawer somewhere, PM or email me.
Thanks Dromede, PM sent. And welcome back

Varti
Title: Re: USB/serial cable for debugging?
Post by: DiTBho on January 30, 2021, 11:42:12 am
are you going to use "kgdb" (kernel gdb stub) through serial?
Title: Re: USB/serial cable for debugging?
Post by: Varti on January 31, 2021, 12:07:09 pm
My plan was to dump the debug messages during kexec's boot, but I believe a debug version of it is required, I tried with the public version and only a "debug" string was sent on the serial port.

Varti
Title: Re: USB/serial cable for debugging?
Post by: DiTBho on January 31, 2021, 12:28:09 pm
I have already done something similar for an embedded PPC40x board, and I am going to "copy" my previous idea to bootstrap my Zaurus.

I want to support tftboot, a way to transfer files over the ethernet, u-boot uses it to bootstrap devices. Unfortunately, the only available versions of "u-boot" for the PXA chip used in Zaurus don't support the usb frame required to support a usb-ethernet driver for tftpboot. Adding it it would require too much work, so I prefer to modify a Linux kernel for this.

Pretty like in kexecboot, but i don't want to support the LCD and keyboard, my final application will redirect the console to the serial port for everything.

bootlader -> serial console
kernel -> serial console + vterm on screen/keyboard