i.mx6 bare-metal JTAG openocd and SDK

[Zozobra]

Our board has NOR flash on EIM CS0.  I can JTAG program the SDK into the NOR flash using openocd.  However, once the SDK is programmed in and boots, it reconfigures some of the registers so that JTAG can no longer modify/erase/read the NOR flash.  I have checked all of the EIM_CS0* registers and they are fine.  I do not understand which other registers I need to modify in order to access the NOR flash vi JTAG again.

Can someone briefly explain what registers may be causing this?

Thanks

[Zozobra]

One more thing, it seems like being able to reset and halt immediately would also help.  That way openocd would not be dependent on what is loaded for access to the EIM NOR Flash.  I have been combing threads on this but have not been succesful yet.

[sinanakman]

Hi Zozobra

After you program the flash, how are you rebooting the image ?

You mention, once the image boots, you can not access NOR.

What response do you get when you issue HALT after the image

boots. Also, which openocd version are you running ? Are you

using one of the config files that came with openocd or do you

have your own config file.

Finally, you might want to post your question to openocd mailing

list or just ask at openocd chat room (#openocd).

Regards

Sinan Akman

[Zozobra · Accepted solution]

The problem was our design had the resets wrong.  JTAG TRST was resetting POR.  Once I rewired the design it worked fine.

[igorpadykov]

Hi Zozobra

one can check if JTAG can to access any other

registers/localtions on processor or memory. If not, then

add some loop in code, so that jtag could be able to connect

to board. Similar problem is described below:

http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka11528.html

Best regards

igor

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