RE: 52840 F version prgram

William.wei — Mon, 13 Dec 2021 08:18:14 GMT

yes, Einar,

Thanks for your quick reply, the root cause is the versions of command line tool, after i update it to the latest, it is working now!

Thanks again.

Regards,

William.

RE: 52840 F version prgram

Einar Thorsrud — Mon, 13 Dec 2021 07:41:51 GMT

Hi William,

The nRF52840 F version has the improved AP protection scheme. So to use that, you need both a recent MDK and recent versions of tools. SDK 17.1.0 includes this, but if using an older SDK, the customer needs to either migrate to SDK 17.1.0, or backport the new MDK (8.40.2 or later) to his old SDK.

The hex file is not actually lost on reset, but if the firmware does not actively disable APPROTECT, it will be enabled again after reset. And then the only way to regain debugger access is to do a recover operation, which deletes the firmware. The solution is to ensure that the firmware you write disable APPROTECT, which will be the case when using a new MDK.

Note that as it is the application that must enable debugging (disable APPROTECT), the SoftDevice can never do this. So you must actually program the application before the SoftDevice in this case, or alternatively together as a merged hex file (though that is not relevant from Keil).

You can point to the official documentation in IN-141.

Einar