LPC8N04 set SWD Pins as GPIO

[DDTD]

Hello everyone,

We are setting up a board with the LPC8N04 where the pins used for the SWD needs to be reassigned as GPIOs. Once the program is flashed and the SWD Pins reassigned, the MCU is not accessible through the SWD pins any more.

Is there a way to restore the configuration to reprogram this MCUs?

I saw the next post where a tool from P&E is needed to unbrick the Kinetis.

The pins in SWD are inadvertently set to normal GPIO 

Regards

[ZhangJennie]

Hi DDTD 

Please try to connect the board in ISP mode. In ISP mode, do mass erase. then try again if you can connect the board then.

( We can bypass application in ISP mode)

Thanks,

Jun Zhang

[DDTD]

Hi @ZhangJennie , thanks for your reply

Did you mean ISP as In-System Programming?

If yes, I look on to the LPC8N04 datasheet and User manual and couldn't find some pin functionality that allows to get into this mode. I'm aware that some MCUs could be entered in this mode setting a pin to desired level and perform a reset.

Do you know how this can be performed for LPC8N04?

Regards.

[ZhangJennie]

Yes LPC8N04 doesn't have ISP mode. (Most of new LPCs has ISP mode but LPC8N04 is a exception)

I currently don't have LPC8N04 to test. But I tested other LPC8xx device, for example LPC824, I set SWD pin as GPIO, next time I can connect board without issue with MCUXpresso IDE.

Best Regards

Jennie

[DDTD]

Hi Jennie, 

Have you been able to test this behavior in a LPC8N04?

We have not been able to recover the Bricked MCUs yet.

Regards

[ZhangJennie]

Hi DDTD 

No, I don't have LPC8N04 board. But I tested it on LPC802 and LPC824 board. I can't reproduce this issue.

Are you sure the problem was caused by setting SWD as GPIO? How many boards have this problem?

If you failed connect SWD, you need also consider other possibilities, for example,  SWD design，boot design,etc.

Thanks,

Jun Zhang