[SOLVED] Sabre-Lite I.MX6Q signal manipulation

RSpliet · Apr 24th 2014, 3:32pm

Dear sir/madam,

Before I decide to purchase a Segger J-Link, I would like to make sure it is usable for my particular use-case. In short, I want to manipulate one of the input signals of the Cortex A9 cores inside the I.MX6Q. I have been informed by Freescale that this can be done using JTag, hence my desire for such a device. I do however have a few concerns:

- Does the Segger J-link and/or software support the challenge/response mechanism for the implemented Secure JTAG implementation?
- Can I use the Segger software to assert a single pin, or do I need additional tools for this?
- How does the software understand which input signal is which? Are there some sort of "netlists" provided with the software? Or is this provided through the JTAG controller? Do I need to request these netlists somewhere else?
- Can I use the Segger J-Link with a 20-pin JTAG to 10-pin microJTAG convertor?

I hope someone can shed some light on this for me. Many thanks in advance. Yours,

Roy

SEGGER - Alex · Apr 29th 2014, 8:46am

Hello Roy,

J-link supports debugging via the standard JTAG interface on the i.MX6.
As far as I understand, the secure JTAG (SJTAG) is a special unit in the i.XM6 which, if enabled,
needs to be initialized with a security key to enable the TAP for regular JTAG debugging.

In general, you can write an application with the J-Link SDK which implements this "authentication" via the SJTAG unit and once this is done,
you should be able to perform operations via the regular debug interface via J-Link, until the unit is secured again (on reset? power-on reset?).

- Can I use the Segger software to assert a single pin, or do I need additional tools for this?

Could you please specify what exactly you mean here?
Of course, J-Link allows access to the peripheral registers of the CPU which of course then also allows toggling on GPIOs etc.
Otherwise, it would be a pretty useless debug tool...

- Can I use the Segger J-Link with a 20-pin JTAG to 10-pin microJTAG convertor?

Yes, why shouldn't you be able to do so?
The Sabre Lite Kit provides a 10-pin Cortex-M connector.

- Alex

hardware@quercus.biz · Nov 3rd 2016, 9:36am

Is it possible to implement the Secure JTAG authentication using J-Link Software and Documentation Pack commands? without J-Link SDK.

How could I read TDO line?
How could I write raw value to TDI? (Is it wjraw command? Can you put an example of use?)

I'm using J-Link Plus with iMX6 Solo.

Thanks in advance for your help.

Joan

SEGGER - Erik · Dec 16th 2016, 12:04pm

Hi Joan,

Is it possible to implement the Secure JTAG authentication using J-Link Software and Documentation Pack commands? without J-Link SDK.

Yes, this can be done using J-Link script files. Further information regarding J-Link script files can be found in the J-Link user manual (UM08001).

How could I read TDO line?
How could I write raw value to TDI? (Is it wjraw command? Can you put an example of use?)

Can also be done using J-Link script files. We do not have an example for the iMX6S device but there are examples for other devices in the J-Link Software and Documentation Package installation directory, which can be used as reference: %INST_DIR%\Samples\JLink\Scripts

Best regards
Erik

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