Pavel Grancharov

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8 years, 6 months ago.

SWD Error on LPC800-MAX

Hi all,

I recently got a LPC800-MAX board - my first development board ever. I was trying to write some simple programs related to PWM. After my last reprogramming of the board I got a fail.txt with a SWD ERROR. The blue LED of the board is constantly on while the RED led is blinking continuously.

It seems that I can't reprogram the board anymore. I guess that I have defined unappropriate pins for the PWM output and the controller is stuck somewhere in my endless loop. I've also switched SJ1 and SJ4 jumpers to get the Virtual COM to work.

I tried some of the tricks mentioned in the forum - tried to drag-n-drop blinky.bin while holding the reset button, but it does't seem to help. I also tried connecting and reprogramming the board to multiple host computers but with no positive result. The last thing I tried was updating the firmware but again nothing happened - the error continued to occur.

Are there any other ways to erase the program from the controller or make some kind of 'factory reset'? Every advice will be helful for me. I can't believe that there is no way to return in to normal operation.

I dont actually have an LPC, I am used to use an FRDMKL25z. But this SWD ERROR happened to me a few times. One thing that worked was to instal an PE Micro firmware and then return to mbed firmaware, but i dont know why ...

posted by Thiago . 06 May 2016

2 Answers

Paul Staron
5 years, 11 months ago.

Old question, in case anyone arrives here.

I had this issue today. Holding p0_12 low during programming allowed re-flashing . Tried bricking it several times to be sure and got it working every time. Prior to that I was replacing the MCU.

Wim Huiskamp
8 years, 6 months ago.

Disabled pins can get you in trouble. Is anything connected to any of the lpc812 pins? Make sure they are all open. Depending on the revision of the chip it could enter ISP mode when p0_12 is low at reset. See here. In case this doesnt work you may need an external programmer like flashmagic to regain control of the bricked lpc812.