Hotplugging with Debugger Circuit – Guidance Needed

[TEMCEFF]

I am working on a project where I need to hotplug a debugger into a running target circuit without resetting or powering down the system. My goal is to maintain the target’s operational state while connecting the debugger for diagnostics.

Could you please clarify:

1. Is hotplugging supported for LPC series?
2. What precautions should be taken to avoid damaging the target or debugger during hot plugging?
3. Are there recommended hardware design considerations (e.g., pull-ups, isolation circuits) for safe hot plugging?
4. Any software steps or debugger settings required to ensure a smooth connection?

If there are official guidelines or application notes on this topic, please share the links.

Thank you for your support!

[Alice_Yang]

Hello @TEMCEFF 

There is an Attach function in MCUXpresso IDE for debugging. When you make a debug connection using this feature, the target continues running until you manually pause it. I believe this can meet your requirement.

BTW, hot-plugging carries certain risks and is not a recommended standard practice. It is not advised.

BR

Alice

[TEMCEFF]

We are not using MCUXpresso IDE, and our focus is primarily on hardware design. Regarding hot-plugging, we would like to know if there are recommended design considerations to ensure reliable insertion and handling. We want to ensure the solution is robust for Code downloading during mass production.

Could you please clarify: Does the LPC series include built-in hot-plugging protection on the debugger interface pins?

[Alice_Yang]

Hello @TEMCEFF 

"Does the LPC series include built-in hot-plugging protection on the debugger interface pins?"

->> No, there is no specific “hot-plugging protection circuit” integrated into the silicon for the debug pins. The pins used for the Serial Wire Debug  interface on LPC microcontrollers (such as SWCLK, SWDIO)  are standard GPIO pins that are multiplexed to the SWD function.

Thank you.

BR

Alice

[TEMCEFF]

Thanks for the confirmation! That’s helpful.

I was specifically curious about whether there are recommended hardware design considerations for safe hot-plugging during mass code downloading? Any best practices you follow?  

[Alice_Yang]

Hello @TEMCEFF 

Which chip are you using? You can find an EVK board for your chip as a reference.

Thank you.

BR

Alice