[S32K146] mcu reset status is JTAG generated reset

[LGY]

I encountered a problem with MCU reset under no simulation conditions, it was found that the reset reason was JTAG generated reset by checking the register RCM>SRS .

What are the reasons for this reset?

Look forward to your reply.

[VaneB]

Hi @LGY 

As it is mentioned in the reference manual(25.2.5.1 JTAG reset): "The JTAG module generates a system reset when certain IR codes are selected. This functional reset is asserted when EXTEST, HIGHZ and CLAMP instructions are active.

The reset source from the JTAG module is released when any other IR code is selected."

B.R.

VaneB

[LGY]

Thanks @VaneB 

JTAG tool is not connected when MCU JTAG reset.
What causes the EXTEST HIGH CLAMP command to be activated without debugging with the JTAG tool?

B.R.

[VaneB]

Hi @LGY 

There is a possibility that a hardware problem is generating the reset.

Please be sure that you are considering good practices for the circuit and layout. In the following link, you can find the Hardware design guidelines recommendations about JTAG for S32K1.

AN5426: Hardware Design Guidelines for S32K1xx – Application Note

[LGY]

Thanks @VaneB
I want to  trigger JTAG RESET, But How to activate EXTEST or HIGHZ command in Jlink commander ?

[VaneB]

Hi @LGY 

Could you help me to clarify which issue you want to solve, so I can help you with it?

[LGY]

Thanks VaneB.

JTAG tool is not connected when MCU JTAG reset.
What causes the EXTEST HIGH CLAMP command to be activated without debugging with the JTAG tool?

B.R.