0 available SWD Devices detected - LPC55s69 OKDO E1

[maciek21]

Hi, Today, by mistake, I'm accidentally disconnect USB cable while uploading program to OKDO E1 eval board with LPC55s69.After that, device has stoped working and just keept red LED ON all the time (Image 0). I tried uploading again a new program "LED blink" from SKD example, but I can't do that beacons I'm getting empty SWD select core window (image 1) and keep getting errors in console (image 2).

I tried some example solutions from this forum, such as accessing DEBUG mode (no result), accessing an ISP (no result) or using the J-LINK command (no result, picture 3).

Also used NXP MagicFlesh tool, tried to mass erased all sectors, and uploading .afx LED blink example file - this time with success but example dosn't work on board, any led doesn't blink (image 4).

I don't have any more ideas what to do with that, so i would like to ask fo your help or any advise. Just hopes that mikrokontroler is still alive.

Best regards.

[maciek21 · Accepted solution]

Solved - but i don't exactly know why, but this worked for me: Pressing RESET button while holding ISP button (no visible effect) and after that i just hold all four button about second ~ red rgb led start blinking. From now i can upload program again.

Taked me some time, but it work so i wille leave this ansewer here.

From user manual: "ISP/User button
When pressed, this button connect sport pin P0_5 to ground. Hold this
button down while pressing and releasing Reset (S4) to force the
LPC55S69 into ISP mode." 

[ZhangJennie]

Your device SWD interface should be disturbed by on chip applications you ever programed. For example, this happens if download low power mode applications which causes SWD disabled.

when LPC is in ISP mode, it bypass user application impact.Thus PC can communicate LPC via SWD interface.