IMXRT1166 custom board : MCU-link-pro SWD connection

Dee_m · ‎08-16-2023

Hi,

We are stuck with SWD connection to a custom board with iMXRT1166.

We are using mcu-link-pro. Thus J7 of the mcu-link-pro is our SWD interface.

We have designed a target header shown below. The JTAG pins should be read by their SWD functionalities. JTAG_MOD (GPIO_LPSR_13) is connected to GND through a 4k7 resistance.

However, we have a doubt regarding the pin 10 connection. As we learnt, for JTAG this should be connected to JTAG_TRSTB (GPIO_LPSR_10), but for SWD this should be connected to POR_B (POR_B has an R-C) through a schottky diode.

1. As the default debug mode is SWD, POR_B should be the default connection for pin 10. Is it correct?

2. Should pin 8 (TDI) be unconnected in SWD mode? Will there be any issue if this is left connected to JTAG_TDI (GPIO_LPSR_12) in SWD mode?

Please correct, if we are doing anything incorrect.

3. Besides, what is to be connected to pin 7 and 9. pin 9 being GND(detect) should be connected to GND, as we guessed. PIn 7 is labeled IF_ISPEN, what should be connected here?

Please help.

The MCU-Link_pro debug header schematic is attached.

Pavel_Hernandez · ‎08-17-2023

Hello, my name is Pavel, and I will be supporting your case, I suggest reviewing the information in the Hardware development guide. Chapter 5. Debugging and programming.

Best regards,
Pavel

Dee_m · ‎08-17-2023

Extremely sorry. But, that was more confusing.

I could not match the pinout of 20-pin debug-header J21 of IMXRT1050-EVKB with J8 of mcu-link-pro. Moreover, it being a JTAG, we will not be able to access that without burning the JTAG fuse, as the default debug mode is SWD.

Besides, mcu-link-pro J7 being the effective debug header, we would like to connect to that. We would try to keep both SWD and JTAG debug option while designing the board.

My questions are:

For debugging with J7 of the mcu-link-pro:

1. What should be the target connection to pin 10 of J7? Should it be JTAG_TRSTB (GPIO_LPSR_10) as required in JTAG? or POR_B (POR_B has an R-C) through a schottky diode as required in SWD?

As the default debug mode is SWD, POR_B should be the default connection for pin 10. Is it correct?

2. Should pin 8 (TDI) be unconnected in SWD mode? Will there be any issue if this is left connected to JTAG_TDI (GPIO_LPSR_12) in SWD mode?

Please correct, if we are doing anything incorrect.

3. Besides, what is to be connected to pin 7 and 9. pin 9 being GND(detect) should be connected to GND, as we guessed. PIn 7 is labeled IF_ISPEN, what should be connected here?

Please help me on these points.

Thank you.

Pavel_Hernandez · ‎08-21-2023

Hello, I reviewed your information, the J8 is not a JTAG interface is SWD with 20 pins, for that you may need this adapter to use the J21 of the RT1050 as the SWD interface.

However, the default communication is SWD and if you want to switch to JTAG you must be the following steps on the document that I shared in the last message and burn some fuses, but if you do that there is no coming back.

1. What should be the target connection to pin 10 of J7? Should it be JTAG_TRSTB (GPIO_LPSR_10) as required in JTAG? or POR_B (POR_B has an R-C) through a Schottky diode as required in SWD?

As the default debug mode is SWD, POR_B should be the default connection for pin 10. Is it correct?

Yes, you could connect this to the POR_B with the RC and diode and the IC circuit as is show in the schematic of the evk.

2. Should pin 8 (TDI) be unconnected in SWD mode? Will there be any issue if this is left connected to JTAG_TDI (GPIO_LPSR_12) in SWD mode?

These are the primary pins for the interface.

3. Besides, what is to be connected to pin 7 and 9. pin 9 being GND(detect) should be connected to GND, as we guessed. PIn 7 is labeled IF_ISPEN, what should be connected here?

9 GND from the debugger.

Best regards,
Pavel