i.MX RT685 EVK Configuration for external target

[leduclong]

Hi,
I am trying to use LPC-Link 2 debugger on i.MX RT685 EVK to debug an external RT685 MCU on a customized PCB. I have shorted JP3 and move JP2 to 2-3 position for off-board debug. SWD pin at J2 is connected with RT685 + its power line 1V8 on PCB. However, MCUExpresso cannot detect the MCU M33 core. 

May I have your advices about this? 

Thank you for your support!

[leduclong]

Hi XiangJun Rong,

Thank you for your reply.

May I check with you if voltage logic level used for RT685 SWD pins (SWCLK - PIO2_25 and SWDIO - PIO2_26) is corresponding to VDDIO_1 level of the off-board  RT685? In my design, it's 1V8.

Shorting Pin 2 and 3 of JP12 will bring on-board VDDIO1 level to 3V3 and will it damage the off-board RT685 PCB if connect?

Since the off-board has been fully powered (using PCA9420 as well), can I remove the JP2 and connect pin 1 of J2 SWD to the 1V8 power off-board to use it for level-transistor between Link2 and off-board RT685?

Thank you!

[xiangjun_rong]

Hi,

I have checked the data sheet, the RT685 SWD pins (SWCLK - PIO2_25 and SWDIO - PIO2_26) is powered by  VDDIO_1, on your off-board RT685, the two pins are powered by 1.8V, so you have to close pin1&2 of JP12 so that the SWD signals are 1.8V logic.

I think the jumper configuration is correct.

As a test, Pls check the following items:

1)on the Device Manager menu of PC, can you see the icon of LPC-LinkII?

On the RT685-EVK board, can you download application code and debug with correct jumper configuration?

BR

XiangJun Rong

[leduclong]

Hi Xiangjun,

Thank you for your replies. I have tried your recommended jumper configuration.
The PC can detect LPC-LinkII but when I start debug session on MCUExpresso, launch server cannot detect the core M33.

May I know if you have any advices on this case?

Thanks.

[xiangjun_rong]

Hi,

Pls make sure that the three SWD signals on J2 of EVK are connected to your target board: SWCLK, SWDIO and Reset and GND.

Hope it can help you

BR

XiangJun Rong

[xiangjun_rong]

Hi,

I have checked the schematics, if you want to to debug off-board mimxrt685, it is okay to configure the following jumper:

1)close pin2&3 for JP12 so that the VDDIO1 node is 3.3V and power your off-board

2)close JP3 as you have done

3)close pin2&3 of JP2

connect the J2 to off-board SWD connector.

Pls have a try

BR

XiangJun Rong