Unable to access the nRF54L15-DK after all-erase operation

RE: Unable to access the nRF54L15-DK after all-erase operation

Kenneth — Thu, 15 May 2025 15:03:35 GMT

Hello,

The required sequence to allow debugging is to configure both DBGEN and SPIDEN in TAMPC from the application firmware. This is what the pre-programmed firmware does:

TAMPC.PROTECT.DOMAIN[0].DBGEN.CTRL = 0x50fa00f0; // clear write protection
TAMPC.PROTECT.DOMAIN[0].DBGEN.CTRL = 0x50fa0001; // enable signal

TAMPC.PROTECT.DOMAIN[0].SPIDEN.CTRL = 0x50fa00f0; // clear write protection
TAMPC.PROTECT.DOMAIN[0].SPIDEN.CTRL = 0x50fa0001; // enable signal

It's up to you why and when you choose the application to write to the above registers to allow debugging.

For details also see:
https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/tampc.html#register.PROTECT.DOMAIN.DBGEN.CTRL

Also see Figure 1. Debug and trace overview:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/debug.html

The mailbox consist of registers where the CPU and debugger exchange information. The debugger cannot instruct the device to do anything through the mailbox without a corresponding FW which acts upon data from the debugger in the mailbox.

Kenneth

RE: Unable to access the nRF54L15-DK after all-erase operation

Kenneth — Thu, 08 May 2025 18:37:37 GMT

Hello,

I will need to ask internally and get back to you.

Kenneth

RE: Unable to access the nRF54L15-DK after all-erase operation

KPA — Thu, 08 May 2025 06:22:00 GMT

Hii,
Could you kindly provide clarification on the following matters concerning access port protection.

Is it feasible to access the CPU registers through the Mailbox interface by utilizing the CTRL-AP (Control Access Port)? In other words, can I temporarily disable access port protection by modifying the TAMPC.PROTECT registers via the Mailbox interface?

RE: Unable to access the nRF54L15-DK after all-erase operation

Kenneth — Tue, 29 Apr 2025 13:16:19 GMT

Hi,

The chip will by default have access port protection (read back protection) enabled by design.

So it's only an eraseall operation that can clear the access port protection, when eraseall is executed the access port protection is disabled until next reset.

It's possible to disable access port protection by programming the chip with firmware that disable it from the inside (e.g. write appropriate values to the UICR and registers in RAM). This is for instance what happens when you program the chip during developing a project or if you execute a recover operation. The recover operation will program a small program in start of code space that disable access port protection.

Kenneth