topic Re: JLink cannot connect to MCU in LPC Microcontrollers

JLink cannot connect to MCU

wmp — Wed, 25 Dec 2019 15:18:12 GMT

I have made lpc55s69 pcb,and the debug interface on board is JTAG-SWD type.I placed an 100K Ohm pull-up resistor over the SWDIO pin and a same value pull-down resistor on SWCLK pin，referenced to the official EVK.

But when i tried to debug an example project on it with jlink,errors occured.It said:"JLink cannot connect to target"

The software i use is MCUXpressoIDE 11.0.1.

But it seems that my JLink has recognized the mcu,however , just cannot contact with it.

Could anybody tell me whether I made my circuit correct or not ?

Re: JLink cannot connect to MCU

bob_nayar — Tue, 31 Dec 2019 05:00:53 GMT

I recently spent some time getting my LPC55S66 up on my board.

Did you pull the RESET pin up with a resistor (any value from 10K to 100K should be fine)?

Re: JLink cannot connect to MCU

jeremyzhou — Tue, 31 Dec 2019 06:46:26 GMT

Hi ,

Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
1) But it seems that my JLink has recognized the MCU, however, I just cannot contact it. Could anybody tell me whether I made my circuit correct or not?
-- After having a review of the schematic and the command in J-link Commander, I think the schematic is right basically, however, I don't consider the J-link had already recognized the LPC55S66 actually.
I'd like to know whether you try to use the J-link to connect the LPCXpresso LPC55S69 board.

Have a great day,
TIC

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Re: JLink cannot connect to MCU

wmp — Tue, 31 Dec 2019 07:47:57 GMT

No, I don't have a LPCXpresso Board of LPC55S69，because by coincidence I got three samples of this chip ,but it seems no one in the community have ever made a custom board with that except me,which makes me frustrated.A good chip shall not be limited to perform its functions only by official eval board.It should be diy-friendly...

Re: JLink cannot connect to MCU

jeremyzhou — Thu, 02 Jan 2020 06:19:33 GMT

Hi,

Thanks for your reply.
I'd like to suggest you try to use the J-link to connect the LPCXpresso LPC55S69 board, it can help us to determinate the issue is caused by the firmware of Jlink out of date or hardware circuit.
The below figure demonstrates the process of J-link connecting the LPCXpresso LPC55S69 board.

Have a great day,
TIC

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