How to turn off Access Protection?

RE: How to turn off Access Protection?

Einar Thorsrud — Fri, 12 Apr 2024 13:26:19 GMT

[quote user="Shahin97"]Rev 3 on the latest ncs release, [/quote]

I see. That should be no problem then. Do you have updated nRF Command Line tools? If so, and you still see issues, can you share details on how you program the application? (if you for isntance do a eraseall after the recover operation, that would erase the magic word in UICR.APPROTECT that is needed in order to open the debug port (in addition to the SW part).

[quote user="Shahin97"]am I correct in saying nrfjprog --recover" will allow debugger access without erasing the chip? [/quote]

No. The recover operation will first do an erase all operation (which erase all the flash and RAM and opens the debug port for the rest of that debug session). Then it writes to UICR.APPROTECT and writes a small firwmare piece that that writes to APPROTECT.DISABLE after reset. (The latter is overwritten when you flash your application, but by default, nRF Connect applications will write to this on startup unless configured otherwise).

RE: How to turn off Access Protection?

Shahin97 — Fri, 12 Apr 2024 13:09:36 GMT

Rev 3 on the latest ncs release,
am I correct in saying nrfjprog --recover" will allow debugger access without erasing the chip?

RE: How to turn off Access Protection?

Einar Thorsrud — Fri, 12 Apr 2024 13:06:18 GMT

Hi Shahin,

Which SDK version are you using?

The latest revision of the nF52 series devices, including rev 3 of the nRF52832, has an improved access port protectin mechanism that use both hardware and software. This is described in IN142 and in the product specification under Debug and trace. If you use updated SDK and tools, this is handled automatically for you, so that the debug port is opened by or instance a "nrfjprog --recover" operation, and the firmware by default keeps debugger access enabled. However, if you use older SDKs(?) or explicitly lock the access bort (Enabling access port protection mechanism), it will be enabled.

Einar