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Board Bringup - No JTAG Response - What are the most basic requirements for JTAG response?

Question asked by Jeff Krupp on Jun 19, 2015
Latest reply on Jun 26, 2015 by Sinan Akman

Using a custom board very similar to the Sabre Lite using an IMX6 quad core, the board is not booting.  Taking a step back, JTAG does not have a response (see output below) and can not ID the chip.  Power supplies were confirmed to be sequenced properly, are at the proper DC level, and are clean DC for both input supplies and generated supplies VDDARM23_CAP, VDDARM_CAP, and VDDPU_CAP.  Reset circuit signals are also correct, toggling ON 600ms after the supplies are stable.  If the power supplies are ok and the jtag connections are ok, is there anything else that could prevent JTAG from working?

 

I've confirmed also that the jtag tool and cabling works ok by using it on a Sabre Lite board.

 

Thank you for any suggestions you can offer.

 

JTAG circuit:

jtag.png

 

 

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JTAG Output:

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SEGGER J-Link Commander V4.98e ('?' for help)

Compiled May  5 2015 11:01:31

DLL version V4.98e, compiled May  5 2015 11:00:52

Firmware: J-Link ARM / Flasher ARM V4 compiled Mar 31 2015 22:22:18

Hardware: V4.00

S/N: 164102666

Feature(s): JFlash, GDB

IP-Addr.: 255.255.255.255 (DHCP)

VTarget = 3.282V

Info: Could not measure total IR len. TDO is constant high.

Info: Could not measure total IR len. TDO is constant high.

No devices found on JTAG chain. Trying to find device on SWD.

No device found on SWD.

Failed to identify target. Trying again with slow (4 kHz) speed.

Info: Could not measure total IR len. TDO is constant high.

Info: Could not measure total IR len. TDO is constant high.

No devices found on JTAG chain. Trying to find device on SWD.

No device found on SWD.

No device found at all. Selecting JTAG as default target interface.

J-Link>

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