When using 10-pin ARM JTAG/SWD connector for MIMXRT1166, what is the proper way to connect pin 10 (system reset)?
- Connect via diode to POR? In this case, what to do with JTAG_nTRST?
- Connect to JTAG_nTRST?
I noticed that MIMXRT1024-EVK connects pin 10 of the JTAG connector directly to JTAG_nTRST
However JTAG_nTRST is not system reset pin.
The same board MIMXRT1024-EVK uses a reset button and external signal for asserting POR:
Can the external voltage supervisor be connected in the above configuration?
Hi @tbonkers
To me, the answer to all your questions is yes. Let me explain below.
I think that you can refer to the 20 pin J1 debug adapter on the i.MX RT1160-EVK.
The 20 connector, or 10 pin connector on your case (see adapter for segger here) connects JTAG_nRST, POR_B pin, and reset monitor IC directly, trought a diode.
I hope to understand well your question, let me know any comments or further questions you may have.
Diego
Hi @tbonkers
I am sorry I noticed that my previous response is not correct.
I confused by JTAG_nTRST and JTAG_nSRST on the EVK!
For the i.MX RT11xx JTAG_nTRST does not connect to the POR_B, it only connects to GPIO_LPSR_10.
On our the i.MX RT1160-EVK 20 pin J1 SWD/JTAG connector: JTAG_nSRST is connected to i.MX RT1160 POR_B (reset ) and reset IC, NOT JTAG_nTRST. This a correction to my previous comment. The same applies for the i.MX RT1170-EVK.
JTAG_nTRST and JTAG_nSRST are not the same and should not be mixed. See this post from ARM docu.
While writting and checking this I felt confused about the meaning of JTAG_nTRST and JTAG_nSRST, according to the above JTAG_nSRST is used for chip's soft and warm reset and JTAG_nTRST for internal JTAG Tap controller reset.
https://developer.arm.com/documentation/ka001367/latest/
So, now it comes the interesting part, I do not know if there is an standard about the 10 pin connector. But here you should check your debug probe matching your JTAG connection. Because for your application you are free to put JTAG_nTRST on pin 10 of your 10 pin connector. But as we saw, JTAG_nTRST does not goes to MCUs reset pin (POR_B).
Let me put the example of Segger. Segger's 10 adapter from 20 to 10 pin considers pin 10 of 10 pin header to be JTAG_nSRST ( blue), and JTAG_nTRST to be pin 9 (red). For them JTAG_nTRST is not connected by default.
Does this helps? Let me know more about your debugger. Are you going to use a third party debugger or one from us, like MCU-Link PRO?
All the best,
Diego
