USB Serial Downloader mode - IMX6 Quad

[rajniks]

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.

[cameronmadsen]

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.

[igorpadykov]

Hi Raj

iROM code does not check OTG_ID.

Best regards

chip

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[rajniks]

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.

[igorpadykov]

Hi Raj

you can check what boot mode is used by processor reading

SRC Boot Mode Register (SRC_SBMR2), SRC_SBMR1.

Best regards

chip

[rajniks]

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 

[igorpadykov]

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

[rajniks]

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.

[igorpadykov]

Two boards among what "N" ?

I think you can change processor from good board to

problem board (and vice versa) and check.