topic Re: USB Serial Downloader mode - IMX6 Quad in i.MX Processors

USB Serial Downloader mode - IMX6 Quad

rajniks — Fri, 05 Sep 2014 09:15:43 GMT

I have a custom board design in which USB Serial down-loader mode doesn't seem to work. I have been able to connect Lauterbach debugger directly but have not been successful with serial downloader mode.

On my board, I have connected USB_OTG_ID to pin T4 which has ALT3 functionality as OTG_ID. Will this create a problem as I can see on Sabre Smart OTG_ID is connected to Pin W23 which has ALT0 functionality as OTG_ID. Please let me know if the Freescale internal boot code looks only at one of these in order to decide to boot as USB device or host mode.

Re: USB Serial Downloader mode - IMX6 Quad

igorpadykov — Fri, 05 Sep 2014 09:55:28 GMT

Hi Raj

iROM code does not check OTG_ID.

Best regards

chip

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Re: USB Serial Downloader mode - IMX6 Quad

rajniks — Tue, 09 Sep 2014 10:34:12 GMT

Hello,

The problem on my custom board looks like the processor is not going into correct boot mode by switch setting. I initially had a 10K pull down and switch to connect 3.3V. While experimenting when I pull down both the lines to low which is actually "boot from fuses mode" my board gets detected as USB Device and I am able to connect DDR Tester software.

When I try to configure the serial downloader mode by setting boot mode pin 0 as 3.3V and pin 1 as pull down nothing happens.

Why would such a problem exists. I have checked the state of both the boot options and they seem to be at good level when the POR is deasserted. I am getting stuck with this issue and any pointers will be quite helpful.

Re: USB Serial Downloader mode - IMX6 Quad

igorpadykov — Tue, 09 Sep 2014 11:54:07 GMT

Hi Raj

you can check what boot mode is used by processor reading

SRC Boot Mode Register (SRC_SBMR2), SRC_SBMR1.

Best regards

chip

Re: USB Serial Downloader mode - IMX6 Quad

rajniks — Wed, 10 Sep 2014 05:18:45 GMT

Hi Igor,

I am trying to read both registers using lauterbach T32. I am able to see BMOD value changing in the SBMR2 as per my switch settings but SBMR1 remains 0. Is this okay or we are messing something up here?

Regards

Raj

Re: USB Serial Downloader mode - IMX6 Quad

igorpadykov — Wed, 10 Sep 2014 10:17:40 GMT

Hi Raj

in serial mode SBMR1 may be not read.

Probably boot signals are connected (shorted) on board internally to smth.

which causes this beahviour. Is it one board only ?

Is it possible to solder board with minimal set of components and check.

Best regards

igor

Re: USB Serial Downloader mode - IMX6 Quad

rajniks — Wed, 10 Sep 2014 11:24:38 GMT

I am seeing this behavior on two boards that we have built. I am not suspecting any inadvertent shorts as SBRM2 values changes as per the setting done by the switches.

Re: USB Serial Downloader mode - IMX6 Quad

igorpadykov — Wed, 10 Sep 2014 12:21:11 GMT

Two boards among what "N" ?

I think you can change processor from good board to

problem board (and vice versa) and check.

Re: USB Serial Downloader mode - IMX6 Quad

cameronmadsen — Wed, 25 May 2016 18:34:12 GMT

Raj, on the off chance you see this, did you ever resolve the issue? We have a custom Dual board and are seeing the exact same behavior.