Clarification on APPROTECT for nRF52832 revision 3

[pawpec]

Hello!

One of our projects will have nRF52832 replaced in EMS with revision 3 silicone and we wonder if description in Working with the nRF52 Series' improved APPROTECT is valid.

It states that:

In factory state, the [new version of this device] comes with the access port protection enabled. An ERASEALL command via the control access port (CTRL-AP) is required to enable access.

Since we don't have brand new nRF52 revision 3 chips but have them on nRF52DK, we set up access port protection by:

nrfjprog --eraseall
nrfjprog --memwr 0x10001208 --val 0x00

then did power reset to enable access protection and tried to unlock it using:

nrfjprog --eraseall

but that didn't work.

Using

nrfjprog --recover

enabled access towards nRF52832.

So question is - does factory/brand new nRF52832 revision 3 chips have access port protection enabled in a different way compared to 'nrfjprog --memwr 0x10001208 --val 0x00' and 'nrfjprog --eraseall' command can remove it?

[Amanda Hsieh]

Hi,

does factory/brand new nRF52832 revision 3 chips have access port protection enabled in a different way compared to 'nrfjprog --memwr 0x10001208 --val 0x00' and 'nrfjprog --eraseall' command can remove it?

The new nRF52832 revision 3 chips from build codes Gx0 have access port protection (APPROTECT) enabled by default in hardware. This is a change from earlier revisions, where APPROTECT was disabled by default. To disable access port protection on these chips, you must use  nrfjprog command: " nrfjprog --recover " to unlock the device or CTRL-AP ERASEALL operation via Segger J-Link drivers with SWD interface as instructed in the Working with the nRF52 Series' improved APPROTECT.

Regards,
Amanda H.