XIAO BLE drawing 570uA with Zephyr

[sanadan]

I'm working on a project where we're planning to use XIAO BLEs on an OpenThread network, for that we need very low power consumption. I've been trying samples to get low consumption to verify we can use the XIAO on our project, however I just cannot get to lower the consumption on it.

I've been doing multiple tests on different codes, I've tried stuff on the nrf52840DK that uses around 6uA with nrfOnly moded, which is great, but the same code (for example the blinky)  on the XIAO consumes around 550uA. I've also used system_off with the same results, as well as some code some other fellows have posted on other threads.

When I tried sleeping the device using Arduino/bluefruit I was really happy yo see around 22uA consumption on the XIAO, however it just doesn't transfer when using Zephyr projects.

Here's my blinky (with the light off)

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>

/* 1000 msec = 1 sec */
#define SLEEP_TIME_MS   1000

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)

/*
 * A build error on this line means your board is unsupported.
 * See the sample documentation for information on how to fix this.
 */
static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

void main(void)
{
	// int ret;

	// if (!device_is_ready(led.port)) {
	// 	return;
	// }

	// ret = gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
	// if (ret < 0) {
	// 	return;
	// }

	while (1) {
		// ret = gpio_pin_toggle_dt(&led);
		// if (ret < 0) {
		// 	return;
		// }
		k_msleep(SLEEP_TIME_MS);
	}
}

And my prj.conf

CONFIG_GPIO=n
CONFIG_PM_DEVICE=y
CONFIG_SERIAL=n
# nRF board library
CONFIG_DK_LIBRARY=n
#FIX DEL DTS
CONFIG_USB_DEVICE_STACK=n
#LOW POWER CONFIGURATION RELATED
# #Power management
CONFIG_PM=y

Is there anything I'm missing? any XIAO or Zephyr specific configuration I might be missing?

[Einar Thorsrud]

Hi,

There is nothing that sticks out here, and you have disabled serial (logging) which is what I would check first. Which target board do you build for? Can you share the board files? Perhaps you enable something there?

Also, what about the HW? Have you added anything to the module? Or perhaps the module has an onboard regulator that consumes some power or something else?

[sanadan]

Thank you for the reply

I've used the target board xiao_ble, the only thing i've changed in the files is this line

CONFIG_SERIAL=n

Here's the complete file (apologies if its not the ones you're asking, I'm still kind of new)

xiao_ble_defconfig

# SPDX-License-Identifier: Apache-2.0

CONFIG_SOC_SERIES_NRF52X=y
CONFIG_SOC_NRF52840_QIAA=y
CONFIG_BOARD_XIAO_BLE=y

# Enable MPU
CONFIG_ARM_MPU=y

# Enable hardware stack protection
CONFIG_HW_STACK_PROTECTION=y

# enable GPIO
CONFIG_GPIO=y

# enable uart driver
CONFIG_SERIAL=n

# enable console
CONFIG_CONSOLE=y

# enable USB
CONFIG_USB_DEVICE_STACK=y

# Build UF2 by default, supported by the Adafruit nRF52 Bootloader
CONFIG_BUILD_OUTPUT_UF2=y
CONFIG_USE_DT_CODE_PARTITION=y

# additional board options
CONFIG_GPIO_AS_PINRESET=y

CONFIG_PINCTRL=y

xiao_ble.dts

/*
 * Copyright (c) 2022 Marcin Niestroj
 * Copyright (c) 2022 Peter Johanson
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/dts-v1/;
#include <nordic/nrf52840_qiaa.dtsi>
#include "xiao_ble-pinctrl.dtsi"
#include "seeed_xiao_connector.dtsi"

/ {
	model = "Seeed XIAO BLE";
	compatible = "seeed,xiao-ble";

	chosen {
		zephyr,console = &usb_cdc_acm_uart;
		zephyr,shell-uart = &usb_cdc_acm_uart;
		zephyr,uart-mcumgr = &usb_cdc_acm_uart;
		zephyr,bt-mon-uart = &usb_cdc_acm_uart;
		zephyr,bt-c2h-uart = &usb_cdc_acm_uart;
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
		zephyr,code-partition = &code_partition;
		zephyr,ieee802154 = &ieee802154;
	};

	leds {
		compatible = "gpio-leds";
		led0: led_0 {
			gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;
			label = "Red LED";
		};
		led1: led_1 {
			gpios = <&gpio0 30 GPIO_ACTIVE_LOW>;
			label = "Green LED";
		};
		led2: led_2 {
			gpios = <&gpio0 6 GPIO_ACTIVE_LOW>;
			label = "Blue LED";
		};
	};

	pwmleds {
		compatible = "pwm-leds";
		pwm_led0: pwm_led_0 {
			pwms = <&pwm0 0 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
		};
	};

	/* These aliases are provided for compatibility with samples */
	aliases {
		led0 = &led0;
		led1 = &led1;
		led2 = &led2;
		pwm-led0 = &pwm_led0;
		bootloader-led0 = &led0;
		mcuboot-led0 = &led0;
		watchdog0 = &wdt0;
		spi-flash0 = &p25q16h_spi;
	};
};

&adc {
	status = "okay";
};

&gpiote {
	status = "okay";
};

&gpio0 {
	status = "okay";
};

&gpio1 {
	status = "okay";
};

&uart0 {
	compatible = "nordic,nrf-uarte";
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

&i2c1 {
	compatible = "nordic,nrf-twi";
	/* Cannot be used together with spi1. */
	status = "okay";
	pinctrl-0 = <&i2c1_default>;
	pinctrl-1 = <&i2c1_sleep>;
	pinctrl-names = "default", "sleep";
};

&pwm0 {
	status = "okay";
	pinctrl-0 = <&pwm0_default>;
	pinctrl-1 = <&pwm0_sleep>;
	pinctrl-names = "default", "sleep";
};

&spi0 {
	compatible = "nordic,nrf-spi";
	/* Cannot be used together with i2c0. */
	status = "okay";
	pinctrl-0 = <&spi0_default>;
	pinctrl-1 = <&spi0_sleep>;
	pinctrl-names = "default", "sleep";
};

&spi3 {
	status = "okay";
	pinctrl-0 = <&spi3_default>;
	pinctrl-1 = <&spi3_sleep>;
	pinctrl-names = "default", "sleep";
	cs-gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
	p25q16h_spi: p25q16h@0 {
		compatible = "jedec,spi-nor";
		reg = <0>;
		wp-gpios = <&gpio0 22 GPIO_ACTIVE_LOW>;
		hold-gpios = <&gpio0 23 GPIO_ACTIVE_LOW>;
		spi-max-frequency = <104000000>;
		jedec-id = [85 60 15];
		sfdp-bfp = [
			e5 20 f1 ff  ff ff ff 00  44 eb 08 6b  08 3b 80 bb
			ee ff ff ff  ff ff 00 ff  ff ff 00 ff  0c 20 0f 52
			10 d8 08 81
		];
		size = <16777216>;
		has-dpd;
		t-enter-dpd = <3000>;
		t-exit-dpd = <8000>;
	};
};

&ieee802154 {
	status = "okay";
};

&flash0 {
	partitions {
		compatible = "fixed-partitions";
		#address-cells = <1>;
		#size-cells = <1>;

		sd_partition: partition@0 {
			label = "softdevice";
			reg = <0x00000000 0x00027000>;
		};

		code_partition: partition@27000 {
			label = "code_partition";
			reg = <0x00027000 0x000c5000>;
		};

		/*
		 * The flash starting at 0x000ec000 and ending at
		 * 0x000f3fff is reserved for use by the application.
		 *
		 * Storage partition will be used by FCB/LittleFS/NVS
		 * if enabled.
		 */
		storage_partition: partition@ec000 {
			label = "storage";
			reg = <0x000ec000 0x00008000>;
		};

		boot_partition: partition@f4000 {
			label = "adafruit_boot";
			reg = <0x000f4000 0x0000c000>;
		};
	};
};

zephyr_udc0: &usbd {
	compatible = "nordic,nrf-usbd";
	status = "okay";

	usb_cdc_acm_uart: cdc-acm-uart {
		compatible = "zephyr,cdc-acm-uart";
	};
};

I saw a someone with the exact same issue but no solution in a different post.

About HW, I have been using the bare retail xiao, sometimes an expansion board for ease of flashing but when measuring consumption just the bare board, the expansion board ends up consuming like 2mA, just the Xiao consumes around 550 or 570uA.

[Einar Thorsrud]

I see. Are the samples functional or not (except for the current consumption)? I have been trying to find a schematic for the Seeed Studio XIAO nRF52840 without success, do you have it? Perhaps that could shade some light on things.

[Basti_Klein]

You can find the schematic here: https://files.seeedstudio.com/wiki/XIAO-BLE/Seeed-Studio-XIAO-nRF52840-Sense-v1.1.pdf

I found the link on this page: https://wiki.seeedstudio.com/XIAO_BLE/#resources 

[Einar Thorsrud]

Thanks. I don't see anything sticking out in the schematic.

Perhaps the next step should be to check with a debugger which peripherals is in use (start by checking the enable registers). Is anything enabled that you would not expect?

[sanadan]

Thank you Basti_Klein for the schematic.

I will try the debugger and see if anything sticks out, thank you for the help.

I did try measuring the same tests with a newer xiao board and got down to 250uA, however it started creeping up, so my first board might have had something strange. It's still not low enough though, we're already trying other nrf chip and see if we get better results.

[Basti_Klein]

Cool, thanks for checking with the debugger. I am also very much interested in a solution to this issue.
I found an open discussion similar to this issue here: https://github.com/zephyrproject-rtos/zephyr/pull/55199#issuecomment-1457102476
If true, it seems to be a zephyr issue. The open ticket is documented here: https://github.com/zephyrproject-rtos/zephyr/issues/55543

EDIT:

When including these three .config lines I am able to reduce deep sleep current to around 140uA:

CONFIG_FLASH=y

CONFIG_SPI=y

CONFIG_SPI_NOR_IDLE_IN_DPD=y

Einar Thorsrud  Besides some milliseconds to enter and exit deep sleep - does this have any other negative side effects?

[sanadan]

Would you mind sharing your .config file? I tried adding the 3 lines but get undefined reference to `__device_dts_ord_10' , so I couldn't replicate it.

Thank you for linking the Zephyr issue, I'll keep checking on it to see if there's a solution at some point.