Jtag connection issue

[gauravverma]

Hello,

In our custom design(with out CPLD), there are two t1024 processor supplied by identical different power supplies.... I am able to connect jtag with corewarrior for one processor but not with other processor and getting error related to IR length.... What can be possible reason of this issue??.. I can see toggling of clk, tms and tdi.... But occasional toggling on tdo line....

What can be possible reason of this issue??.

Regards

Gaurav

[yipingwang]

The IR scan test uses the TCK and TMS pins to move the target into the Shift-IR state, and then sends a long
test pattern through the IR by holding TMS=0, clocking TCK, and feeding the test pattern bits in the TDI pin.
It captures the bits coming out on the TDO pin. If the connection is working correctly, the TDI bits pass through
the IR shift register (instruction register) and eventually show up on the TDO pin. The test compares the TDO
data it captures against the TDI test pattern it sent to see if TDO contains the test pattern. It expects to find the
test pattern in the TDO, but bit-shifted to the left by some number of bits (corresponding to the IR length).
If it fails to find the test pattern, then the test reports an error, Error testing IR scan.
If the test fails to measure the length of the instruction register, then an error, Error measuring IR length, is
thrown.

If there is no valid RCW on the target board, please use hard-coded RCW or JTAG configuration file in CodeWarrior, please refer to "8.4 Setting up a remote system to use a JTAG configuration file" in C:\Freescale\CW_PA_v10.5.1\PA\Help\PDF\Targeting_PA_Processors.pdf

[gauravverma]

Hello,

What could be possible reason for no event on TDO.... as per Gerber all lines are ok....power supply sequence n levels are as per datasheet....

I have set RCW in SPI boot mode and used 1200_800_1200 jtag file for initialization...

Does wrong RCW may cause non event on TDO line??

As I mentioned in previous post ... One T1024 on the board working fine.... Problem is getting in other one...

Thanks

Gaurav

[yipingwang]

Please try hard-coded RCW or use CodeWarrior JTAG configuration file overriding on the target board.

[gauravverma]

hello,

I tried this but no luck....

What should be the maximum trance length for JTAG lines ?.... in my design its between 7045 mills to 7818 mills ....

For the working processor, jtag trace length is  between 4504 mills to 5553 mills.

Regards

Gaurav

[yipingwang]

I do not think this is the cause of the problem. Please make sure that the two T1040 chips have identical schematics from JTAG/reset/supply/POR pin settings, etc. Also make sure that the two jatag connectors have same pinout, i.e, there is no mistake of layout to pin rows or columns or order, etc.  You might need to do so probing to the connector that does not work, search for opens, shorts, etc.

If this problem happen on all boards then there must be some real issue in the schematics/ manufacturing of the board.

[gauravverma]

Dear Yiping,

I removed all the peripherals for the second processor except DDR3 and SPI flash ... and now i am getting no error related to JTAG diagnostics...... 

But i am getting some other error  related to "core not responding ( detailed log is attached)... Some time i am getting error like "invalid parameters"

Any suggestion for this problem??

Regards

Gaurav

[gauravverma]

Hello,

I will recheck again.....

Can EMI/EMC be an issue?? .... The non-working processor is placed near to power supplies.... Though supplies looks stable on oscilloscope...

Regards

Gaurav

[sinanakman]

Hi Gaurav

Which JTAG probe are you using ? Also please make sure both T1024 on your board are powered properly.

Hope this helps.

Sinan Akman

[gauravverma]

Hello Akmal,

Power supply looks ok as per datasheet...

Our jtag connection is a bit different...

1. We have taken out jtag line on 20pin connector...

2. Then we have made piggybag module for voltage translation as per T1024RDB and given out to another 20 pin header as per jtag connection for debugger....

I tried to connect jtag at speed of 100kHz so does not look like integrity issue...

Regards

Gaurav