What is the nPM1100 Evaluation Kit
Installing nRF Connect and the SEGGER Embedded Studio
The code
Connecting the hardware
Evaluating power consumption
Next steps

Published January 31, 2023 © GPL3+

Getting Started with the nPM1100 Evaluation Kit

Use the nPM1100 EK and an nRF52840 to create a BLE project that can be easily charged and powered efficiently.

BeginnerProtip1 hour308

Getting Started with the nPM1100 Evaluation Kit

Things used in this project

Hardware components

Nordic Semiconductor nPM1100 EK

Nordic Semiconductor nRF52 Development Kit

nRF52840 variant

Nordic Semiconductor Power Profiler Kit

Software apps and online services

Nordic Semiconductor nRF Connect SDK

Story

What is the nPM1100 Evaluation Kit?

All too often, the circuitry required for both charging a device's battery and efficiently regulating it down takes up much of a PCB's limited real-estate, so finding ways to combine these functions in a tiny footprint is vital. This is where the nPM1100 from Nordic Semiconductor can help, as it's a single 2x2mm integrated circuit that holds advanced functionality for charging LiPo batteries at charging currents between 20 through 400mA and stepping down their voltage from 3.7v to either 1.8, 2.1, 2.7, or 3v at up to 92% efficiency. The IC is also intelligent since it can automatically switch the charging mode.

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Installing nRF Connect and the SEGGER Embedded Studio

In order to easily program the nRF52840 and view the power draw with the PPK II, Nordic Semiconductor's nRF Connect and the nRF Command Line Tools must first be installed. To do so, simply find the platform and version you need for your development machine from this page and click the installer to download it. If your machine is Linux or macOS based, you'll have to install the SEGGER J-Link Software separately. Make sure to also install all of the drivers so your board can communicate with your machine. The CLI tools can be found here. Once nRF Connect for Desktop is finished installing, go down the list of software packages an click "Install" for the following:

Bluetooth Low Energy
Getting Started Assistant (if you're new to the platform)
Power Profiler
Programmer
Toolchain Manager

This last one is a bit more involved. Upon opening it, click on the "Install" button next to "nRF Connect SDK v2.1.2" under the "SDK Environments" tab, then click on "Open VS Code" to start the environment. If the required extensions aren't already present, they can be installed by clicking the "Install missing extensions" button.

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The code

Opening a short example project was quite simple. I started by creating a new application in the nRF Connect extension tab wherein I chose the newly installed SDK/toolchain version and the nrf/bluetooth/peripheral_lbs example. The peripheral_lbs sample project sets up the nRF52840 DK's four LEDs and two buttons to interact with a user via Bluetooth Low Energy. In addition to creating a new project, I also added a new build configuration for the project under the "Applications" tab.

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My first modification to the sample project involved turning off the advertising services of the BLE radio when a user connects since this device will have just one at most. Second, the device will go into the PM_STATE_SOFT_OFF state when button 3 is pressed to demonstrate potential power savings of different sleep modes.

Connecting the hardware

This project utilizes the nPM1100 Evaluation Kit (EK) in order to easily expose its pins. Additionally, it uses the Power Profiler Kit II (PPK II) and nRF52840 Development Kit (DK) from Nordic Semiconductor. To begin, connect the VOUT pin on the PPK II to the nPM1100 EK's VBUS pin, as well as attaching both of their GND pins together. Next, attach a jumper wire from the nPM1100 EK's VOUTB pin to the nRF52840 DK's VIN pin on the External supply header. And again, connect the GND pins of both boards together.

From https://infocenter.nordicsemi.com/pdf/nPM1100_EK_User_Guide_v0.8.0.pdf

Evaluating power consumption

With the hardware all connected, I connected the PPK II to my PC via USB and selected it from the "Select Device" menu within the Power Profiler app.

I set the output voltage to around 4.5V and made sure to enable the power output on the PPK II.

Then I sampled the current consumption for 121 seconds at 100, 000 samples per second, thus generating this nice chart:

The first section is simply the nRF52840 sending BLE advertising packets whilst blinking LED1, and that continues nearly the entire time, hence the 1-second large "bumps" in the graph. The second portion is when the client device has connected and is actively sending data to the DK and receiving acknowledgement packets back. The highest level of current consumption came from turning on the third LED with the client device. As mentioned before, the third button causes the DK to enter into the PM_STATE_SOFT_OFF power state which causes many of the peripherals to shut off and therefore giving the lowest power consumption. Assuming there were a device with a 1200mAh battery, it could last for around 5 days without needing to be charged, but because of the great features in the nPM1100 EK, the battery can be trickle charged when not in use or provide constant voltage when it is.

Next steps

Whether it's the desire to add efficient voltage boosting or a charge controller with a tiny footprint to a small, portable device, the nPM1100 EK is a great choice for building one. And when combined with the ability to charge at up to 400mA with automatic USB port detection, the 2x2mm IC looks even better. For more information about the nPM1100 PMIC or its evaluation kit, you can view it on Nordic Semiconductor's site here.

Code

peripheral_lbs_modified.c

/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

#include <zephyr/types.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include <pm/pm.h>
#include <zephyr/sys/printk.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>
#include <soc.h>

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/hci.h>
#include <zephyr/bluetooth/conn.h>
#include <zephyr/bluetooth/uuid.h>
#include <zephyr/bluetooth/gatt.h>

#include <bluetooth/services/lbs.h>

#include <zephyr/settings/settings.h>

#include <dk_buttons_and_leds.h>

#define DEVICE_NAME             CONFIG_BT_DEVICE_NAME
#define DEVICE_NAME_LEN         (sizeof(DEVICE_NAME) - 1)


#define RUN_STATUS_LED          DK_LED1
#define CON_STATUS_LED          DK_LED2
#define RUN_LED_BLINK_INTERVAL  1000

#define USER_LED                DK_LED3

#define USER_BUTTON             DK_BTN1_MSK
#define SLEEP_BUTTON            DK_BTN3_MSK

static bool app_button_state;

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

static const struct bt_data sd[] = {
	BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_LBS_VAL),
};

static void connected(struct bt_conn *conn, uint8_t err)
{
	if (err) {
		printk("Connection failed (err %u)\n", err);
		return;
	}

	printk("Connected\n");

	dk_set_led_on(CON_STATUS_LED);

    err = bt_le_adv_stop();
	if (err) {
		printk("Advertising failed to start (err %d)\n", err);
		return;
	}
}

static void disconnected(struct bt_conn *conn, uint8_t reason)
{
	printk("Disconnected (reason %u)\n", reason);

	dk_set_led_off(CON_STATUS_LED);

    int err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad),
			      sd, ARRAY_SIZE(sd));
	if (err) {
		printk("Advertising failed to start (err %d)\n", err);
		return;
	}
}

#ifdef CONFIG_BT_LBS_SECURITY_ENABLED
static void security_changed(struct bt_conn *conn, bt_security_t level,
			     enum bt_security_err err)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	if (!err) {
		printk("Security changed: %s level %u\n", addr, level);
	} else {
		printk("Security failed: %s level %u err %d\n", addr, level,
			err);
	}
}
#endif

BT_CONN_CB_DEFINE(conn_callbacks) = {
	.connected        = connected,
	.disconnected     = disconnected,
#ifdef CONFIG_BT_LBS_SECURITY_ENABLED
	.security_changed = security_changed,
#endif
};

#if defined(CONFIG_BT_LBS_SECURITY_ENABLED)
static void auth_passkey_display(struct bt_conn *conn, unsigned int passkey)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	printk("Passkey for %s: %06u\n", addr, passkey);
}

static void auth_cancel(struct bt_conn *conn)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	printk("Pairing cancelled: %s\n", addr);
}

static void pairing_complete(struct bt_conn *conn, bool bonded)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	printk("Pairing completed: %s, bonded: %d\n", addr, bonded);
}

static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	printk("Pairing failed conn: %s, reason %d\n", addr, reason);
}

static struct bt_conn_auth_cb conn_auth_callbacks = {
	.passkey_display = auth_passkey_display,
	.cancel = auth_cancel,
};

static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
	.pairing_complete = pairing_complete,
	.pairing_failed = pairing_failed
};
#else
static struct bt_conn_auth_cb conn_auth_callbacks;
static struct bt_conn_auth_info_cb conn_auth_info_callbacks;
#endif

static void app_led_cb(bool led_state)
{
	dk_set_led(USER_LED, led_state);
}

static bool app_button_cb(void)
{
	return app_button_state;
}

static struct bt_lbs_cb lbs_callbacs = {
	.led_cb    = app_led_cb,
	.button_cb = app_button_cb,
};

static void button_changed(uint32_t button_state, uint32_t has_changed)
{
	if (has_changed & USER_BUTTON) {
		uint32_t user_button_state = button_state & USER_BUTTON;

		bt_lbs_send_button_state(user_button_state);
		app_button_state = user_button_state ? true : false;
	} else if (has_changed & SLEEP_BUTTON) {
        dk_set_led(RUN_STATUS_LED, 0);
        dk_set_led(CON_STATUS_LED, 0);
        dk_set_led(USER_LED, 0);

        bool sleeping = pm_state_force(0, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

        if (!sleeping) printk("ERROR: System off failed\n");
        while (true) {
            /* spin to avoid fall-off behavior */
        }
    }
}

static int init_button(void)
{
	int err;

	err = dk_buttons_init(button_changed);
	if (err) {
		printk("Cannot init buttons (err: %d)\n", err);
	}

	return err;
}

void main(void)
{
	int blink_status = 0;
	int err;

	printk("Starting Bluetooth Peripheral LBS example\n");

	err = dk_leds_init();
	if (err) {
		printk("LEDs init failed (err %d)\n", err);
		return;
	}

	err = init_button();
	if (err) {
		printk("Button init failed (err %d)\n", err);
		return;
	}

	if (IS_ENABLED(CONFIG_BT_LBS_SECURITY_ENABLED)) {
		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
		if (err) {
			printk("Failed to register authorization callbacks.\n");
			return;
		}

		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
		if (err) {
			printk("Failed to register authorization info callbacks.\n");
			return;
		}
	}

	err = bt_enable(NULL);
	if (err) {
		printk("Bluetooth init failed (err %d)\n", err);
		return;
	}

	printk("Bluetooth initialized\n");

	if (IS_ENABLED(CONFIG_SETTINGS)) {
		settings_load();
	}

	err = bt_lbs_init(&lbs_callbacs);
	if (err) {
		printk("Failed to init LBS (err:%d)\n", err);
		return;
	}

	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad),
			      sd, ARRAY_SIZE(sd));
	if (err) {
		printk("Advertising failed to start (err %d)\n", err);
		return;
	}

	printk("Advertising successfully started\n");

	for (;;) {
		dk_set_led(RUN_STATUS_LED, (++blink_status) % 2);
		k_sleep(K_MSEC(RUN_LED_BLINK_INTERVAL));
	}
}

Credits

Evan Rust

120 projects • 1054 followers

IoT, web, and embedded systems enthusiast. Contact me for product reviews or custom project requests.

Getting Started with the nPM1100 Evaluation Kit

Things used in this project

Hardware components

Software apps and online services

Story

What is the nPM1100 Evaluation Kit?

Installing nRF Connect and the SEGGER Embedded Studio

The code

Connecting the hardware

Evaluating power consumption

Next steps

Schematics

Wiring

Code

peripheral_lbs_modified.c

Credits

Evan Rust

Comments

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Getting Started with the nPM1100 Evaluation Kit

Getting Started with the nPM1100 Evaluation Kit

Things used in this project

Hardware components

Software apps and online services

Story

What is the nPM1100 Evaluation Kit?

Installing nRF Connect and the SEGGER Embedded Studio

The code

Connecting the hardware

Evaluating power consumption

Next steps

Schematics

Wiring

Code

peripheral_lbs_modified.c

Credits

Evan Rust

Comments

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