nrf5340 spi power consumption

RE: nrf5340 spi power consumption

Menon — Thu, 17 Jul 2025 20:08:21 GMT

Hello,

Glad to hear that it resolved your issue and thank you for sharing the solution here.

Kind Regards,

Abhijith

RE: nrf5340 spi power consumption

th8d — Thu, 17 Jul 2025 17:34:46 GMT

The pin that is drawing the current is p0.0b which is the chip select line for the mx25r64 external flash on the nrf7002dk board. Configuring this pin as an input is useful for tracking down the problem. However it is problematic for a long term solution. Is there a way to configure zephyr to put this pin into low power mode using the existing drivers ?

RE: nrf5340 spi power consumption

th8d — Thu, 17 Jul 2025 15:48:45 GMT

Thanks Abhijith that was a useful suggestion.

configuring the gpio0 pin11 (chip select for mx25r64) as an input reduced the current down to 3 uA.

this was achieved with this overlay:

/{
inputs {
compatible = "gpio-keys";
mx_cs: mx_cs {
gpios = <&gpio0 11 (GPIO_ACTIVE_LOW)>;
label = "mx cs";
};

};
};

and this code:

static const struct gpio_dt_spec mx_cs = GPIO_DT_SPEC_GET(DT_NODELABEL(mx_cs), gpios);

gpio_pin_configure_dt(&mx_cs, GPIO_INPUT);

changing the sck, mosi or miso pins did not make any difference to the current

RE: nrf5340 spi power consumption

th8d — Thu, 17 Jul 2025 14:09:39 GMT

can you provide an example of configuring a GPIO pin to low-power state

RE: nrf5340 spi power consumption

Menon — Thu, 17 Jul 2025 13:39:23 GMT

Hello,

Can you check if its associated with GPIO pins (SCK, MOSI, MISO, CS) remaining in an active state though you have suspended the SPI. Try reconfiguring these GPIOs to low-power states to confirm if they are the sources of the excess current you are seeing.

Kind Regards,

Abhijith

RE: nrf5340 spi power consumption

th8d — Tue, 15 Jul 2025 09:17:22 GMT

Hi Menon

Thankyou for your response.

The academy link you provided uses driver level code. If possible, I would like to resolve the problem using my simple application level example before I move into drivers.

I updated my code to create a pointer to the SPI device and then called pm_device_action_run() with PM_DEVICE_ACTION_SUSPEND. I expected this to suspend the SPI device.

I confirmed that the spim_suspend function was getting called inside the spi_nrfx_spim.c driver. However the current remained at 130 uA.

I am not sure why the current is at 130 uA if the spi is suspended. Is there a step I am missing ?

Here is the updated code and prj.conf files:

static const struct device* const SpiDev = DEVICE_DT_GET(DT_NODELABEL(spi4));
int main(void)
{
pm_device_action_run(SpiDev, PM_DEVICE_ACTION_SUSPEND);
while(1) { k_msleep(1000); }

return 0;
}

CONFIG_SERIAL=n
CONFIG_SPI=y

CONFIG_PM=y
CONFIG_PM_DEVICE=y
CONFIG_PM_DEVICE_RUNTIME=y

RE: nrf5340 spi power consumption

Menon — Fri, 27 Jun 2025 14:05:35 GMT

Hello,

Yes, this could be because the peripheral remains active. I recommend suspending the SPI device when it's not needed. See the Device Power Management section from the Academy.

Kind Regards,

Abhijith