IMX6DL JTAG and Trace line clarification

[bryan_crouse]

Hi,

I will be using Lauterbach Trace32 that supports both JTAG and Trace debugging.  This debugger uses an ARM MIPI-38 to connect to the trace/JTAG lines or it can use both a MIPI-38 and separate JTAG connector for debugging and tracing.

My question is on the following debug lines:

JTAG_DE_B

ARM_EVENTI

ARM_EVENTO

I am not sure how these should be connected in hardware.  The documentation is not clear on what is needed.  I see some implementations where JTAG_DE_B is connected to the debugger DBGRQ pin and some were JTAG_DE_B is permanently pulled high.  What is the recommended practice?

Also, do ARM_EVENTI and ARM_EVENTO need to be connected?  Pulled high, low, left floating?

[Yuri]

Hello,

  The DE_B pad (JTAG Debug Enable) is dedicated for external debug request /acknowledge.

This pin is used to propagate a debug request to the core after programming of the JTAG.

Usually this pin is controlled by an external debugger using special hardware probe, therefore

this pin should not be directly connected to GND or VDD. That is, some pulling (thru resistor) is

recommended.

The EVENTI\O signals are specific ARM ones:

EVENTI - External coherent agent Event input for Cortex-A9 processor wake-up from WFE state.

EVENTO - Event output. This signal is active when one SEV instruction is executed.

For more details please refer to the following

ARM Information Center 

  If Your probe debug interface has these signals - just connect them.

Have a great day,
Yuri

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[bryan_crouse]

Hi Yuri,

From reading this ARM document, the ARM_EVENTI and ARM_EVENTO are not a part of the ARM MIPI-38 trace functionality and should not be connected, correct?  

I thought that ARM_EVENTI and ARM_EVENTO could be related to Mictor 38 interface pins "DBGRQ" and "DBGACK" but this not the case, it would seem.

Regards,

Bryan

[Yuri · Accepted solution]

Hello,

  You are right.

Regards,

Yuri.