Chip Startup Sequence

[Jing Luo]

Hello, I would like to inquire about some technical details regarding the internal module power supply ranges, power-up sequences, and reset voltages for the nRF54L05, nRF54L15, nRF52805, and nRF52820:

1. The startup sequence during a power ramp-up (increasing voltage).

2. The voltage threshold that triggers a reset during a power ramp-down (decreasing voltage).

3. The time from when the core starts until Flash operations or access is available during the startup phase.

4. If the Power-Fail Comparator (POF) is configured, the time from when the core starts until the POF becomes effective during the startup phase.

It has been confirmed that there is no relevant information available on the one we inquired about. If the above-mentioned chips differ under these circumstances, please explain them separately.

[Håkon Alseth]

Hi,

 

The startup sequence during a power ramp-up (increasing voltage).

 Please see here:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/_tmp/nrf54l15/autodita/RESET/parameters.startup_time.html

The voltage threshold that triggers a reset during a power ramp-down (decreasing voltage).

Brown-out reset (BOR) voltage levels is mentioned here:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/_tmp/nrf54l15/autodita/REGULATORS/parameters.power_fail.html

The time from when the core starts until Flash operations or access is available during the startup phase.

Once the system is executing its very first instruction; you are powered up.

Please see here: https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/_tmp/nrf54l15/autodita/CPU/parameters.cpu_wakeup_time.html

 

If the Power-Fail Comparator (POF) is configured, the time from when the core starts until the POF becomes effective during the startup phase.

The POF needs to be configured from the cpu, ie. you will need to have a running system in order to configure POF.

 

Kind regards,

Håkon

[Jing Luo]

Hi，
I encountered some issues enabling POFCON in NCS. Although I added the following configuration in the dts and it appears to be effective in output/zephyr.dts, during debugging I observed that the register did not take effect. Are there any required .config settings or other considerations I need to be aware of?

regulators: regulator@120000 {
	compatible = "nordic,nrf54l-regulators";
	reg = < 0x120000 0x1000 >;
	status = "okay";
	#address-cells = < 0x1 >;
	#size-cells = < 0x1 >;
	vregmain: regulator@120600 {
		compatible = "nordic,nrf5x-regulator";
		reg = < 0x120600 0x1 >;
		status = "okay";
		regulator-name = "VREGMAIN";
		regulator-initial-mode = < 0x1 >;
	};
	pofcon: pofcon@120530 {
		compatible = "nordic,nrf-pofcon";
		reg = < 0x120530 0x5 >;
		status = "okay";
		pofcon-name = "POFCON";
	};
};

debug record:

Kind regards,

Jing

[Håkon Alseth]

Hi,

 

Unfortunately, there is no yaml-bindings for "nordic,nrf-pofcon", so that snippet will not work.

I would recommend that you manually enable CONFIG_NRFX_POWER=y and include the appropriate header, then call "nrfx_power_pof_init(..)" with your wanted configuration and evt handler.

 

Kind regards,

Håkon