nRF9151 sch design problem

RE: nRF9151 sch design problem

ketiljo — Thu, 09 Jan 2025 14:37:02 GMT

Hi Sean

[quote user="Sean zheng"]Is it possible to provide this?[/quote]

The device comes out of reset as soon as the voltage is stable. The best is to measure this. Set a pin and measure the time between reset release and pin set.

Depending on the requirement, you might find it better to just set the nRF9151 in PSM mode. See

https://docs.nordicsemi.com/bundle/ps_nrf9151/page/_tmp/alta.nRF9151/autodita/APPLICATION.CURRENT/parameters.id_current_modem_pc_3.html

You can estimate the power draw with this: https://devzone.nordicsemi.com/nordic/power/w/opp/3/online-power-profiler-for-lte

[quote user="Sean zheng"]Could you recommend the minimum RC reset circuit parameters for the nRESET pin?[/quote]

The reset circuitry are internal, the external components are just for noise decoupling see https://docs.nordicsemi.com/bundle/nwp_056/page/WP/nwp_054/nreset.html

[quote user="Sean zheng"]Additionally, what is the minimum duration that nRESET needs to be held to ensure a hardware reset of the chip?[/quote]

It's level trigged, timing doesn't matter

Cheers,

Ketil

RE: nRF9151 sch design problem

sean — Wed, 08 Jan 2025 01:05:38 GMT

Hi，

Thank you for your response. Regarding the third question, what we need here is a power-up sequence diagram for the power supply and nRESET. Is it possible to provide this?

Since we are turning off the power supply to the nRF9151 to save power, we need to quickly power up the chip and run the program. Could you recommend the minimum RC reset circuit parameters for the nRESET pin? Additionally, what is the minimum duration that nRESET needs to be held to ensure a hardware reset of the chip?

RE: nRF9151 sch design problem

ketiljo — Tue, 07 Jan 2025 13:00:01 GMT

[quote user=""]1.What are the main functions of the chip's COEX0, COEX1, and COEX2 pins? If they are used to enable/disable the GPS and cellular modules, which has higher priority: internal software control or COEX control?[/quote]

See https://docs.nordicsemi.com/bundle/nwp_056/page/WP/nwp_054/coex_if.html

The COEX pins are controlled directly by the modem.

[quote user=""]2.Due to the small size of the PCB, we plan to design the GPS with a passive antenna. Can we remove the SKY15943-11 chip? If SKY15943-11 chip is not used, what other impacts might arise?[/quote]

You need ether an active GPS antenna, or a passive antenna with a LNA. Using only a passive GPS antenna is not recommended. https://docs.nordicsemi.com/bundle/nwp_056/page/WP/nwp_054/antenna.html

[quote user=""]3.We need to understand the power-up sequence requirements for the chip and the timing requirements for nRESET; How soon after power-up can the chip start running to the main function?[/quote]

It highly depends on what firmware is running on your device, but in most cases it is in the hundreds of milliseconds range, depending on logging etc. in the secure-side image(s) running.

[quote user=""]4.Could you provide a brief description of what the AUX pin is used for? During product design, should we pay attention to it or reserve space for it?[/quote]

https://docs.nordicsemi.com/bundle/nwp_056/page/WP/nwp_054/aux_if.html. If you don't need it, you can leave it floating.