nRF52840 SWD download with nRESET

[Poki Huang]

Hi Nordic

A simple question

When using SWD download, do we need control nRESET(P0.18) pin?

Thank you~~

BR/Poki

[Turbo J]

Poki Huang said:

When using SWD download, do we need control nRESET(P0.18) pin?

Not really. You don't need it for production programming.

However, R&D is a different situation. You need the nRESET for the "recovery" in case you lock yourself out of the device - there are several ways to disable SWD communication. Re-enabling the chip (by a flash erase) has VERY tight timing requirements depending on the nRESET signal.