nRF52840 peripheral_uart low power NCS 1.3.0

[Vojislav]

Hi,

I am working with nrf52840dk and using a peripheral_uart example from NCS v1.3.0. and the problem that I am currently having is that I cannot get it to low power. At the moment I have power consumption ~500nA and I suppose this is from UART and Jlink programming pins. 
In the previous release of NCS v1.2.0, I have managed to turn off UART with the Power Management module, but for some reason, this is not working in the new release. More about my previous development is in this issue: nRF52 NCS power consumption. 

A also noticed that on the master branch of ncs-sdk peripheral_uart example has changed a lot.

My question is what is the best way to configure peripheral_uart example to low power?

Best regards,
Vojislav. 

[Amanda Hsieh]

Hi Vojislav, 

I am investigating the issue and need more time to answer. The support staff is reduced during the summer holidays, and you may experience delayed answers.

-Amanda H.

[Vojislav]

Hi Amanda,

Please let me as soon as you know. 

Best regards,
Vojislav

[Vojislav]

Hi Amanda,

I am back on this issue and still having problems with power consumption. My current setup is nrf52840dk and PPK on top. SB40 is cut and I am measuring current with nRF Connect Power Profiler APP. 

My current profile looks like this:

As you can see from the picture the average current between advertising packets is ~530uA. 

My main file has:

static void led_blink_thread(void)
{
	int    blink_status       = 0;
	int    err                = 0;

	LOG_INF("Starting Nordic UART service example\n");

	// err = init_uart();
	// if (err) {
	// 	error();
	// }
	
	int rc = STATS_INIT_AND_REG(smp_svr_stats, STATS_SIZE_32,
	    "smp_svr_stats");

	if (rc < 0) {
		LOG_ERR("Error initializing stats system [%d]", rc);
	}

	/* Register the built-in mcumgr command handlers. */
#ifdef CONFIG_MCUMGR_CMD_FS_MGMT
	rc = fs_mount(&littlefs_mnt);
	if (rc < 0) {
		LOG_ERR("Error mounting littlefs [%d]", rc);
	}

	fs_mgmt_register_group();
#endif
#ifdef CONFIG_MCUMGR_CMD_OS_MGMT
	os_mgmt_register_group();
#endif
#ifdef CONFIG_MCUMGR_CMD_IMG_MGMT
	img_mgmt_register_group();
#endif
#ifdef CONFIG_MCUMGR_CMD_STAT_MGMT
	stat_mgmt_register_group();
#endif
#ifdef CONFIG_MCUMGR_SMP_BT
	//start_smp_bluetooth();
#endif
#ifdef CONFIG_MCUMGR_SMP_UDP
	start_smp_udp();
#endif


	configure_gpio();

	bt_conn_cb_register(&conn_callbacks);

	if (IS_ENABLED(CONFIG_BT_GATT_NUS_SECURITY_ENABLED)) {
		bt_conn_auth_cb_register(&conn_auth_callbacks);
	}

	err = bt_enable(NULL);
	if (err) {
		error();
	}

	LOG_INF("Bluetooth initialized\n");
	k_sem_give(&ble_init_ok);

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

	err = bt_gatt_nus_init(&nus_cb);
	if (err) {
		LOG_ERR("Failed to initialize UART service (err: %d)\n", err);
		return;
	}
	
	/* Initialize the Bluetooth mcumgr transport. */
	smp_bt_register();

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

	/* using __TIME__ ensure that a new binary will be built on every
	 * compile which is convient when testing firmware upgrade.
	 */
	LOG_INF("build time: " __DATE__ " " __TIME__);

	// uart_irq_rx_disable(uart);
	// device_set_power_state(uart, DEVICE_PM_OFF_STATE, NULL, NULL);


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

void ble_write_thread(void)
{
	/* Don't go any further until BLE is initailized */
	k_sem_take(&ble_init_ok, K_FOREVER);

	for (;;) {
		/* Wait indefinitely for data to be sent over bluetooth */
		struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,
						     K_FOREVER);

		if (bt_gatt_nus_send(NULL, buf->data, buf->len)) {
			LOG_ERR("Failed to send data over BLE connection\n");
		}

		k_free(buf);

		if (rx_disabled) {
			rx_disabled = false;
			uart_irq_rx_enable(uart);
		}
	}
}

And my prj.conf:

CONFIG_NCS_SAMPLES_DEFAULTS=y

CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_UART_0_NRF_FLOW_CONTROL=y
CONFIG_SERIAL=n
CONFIG_GPIO=y

# Make sure printk is not printing to the UART console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

CONFIG_HEAP_MEM_POOL_SIZE=2048

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=1

# Enable the NUS service
CONFIG_BT_GATT_NUS=y

# Enable bonding if one of this four is enabled the application wont build with mcuboot
CONFIG_BT_SETTINGS=y
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y
CONFIG_NVS=y
CONFIG_SETTINGS=y

# Enable DK LED and Buttons library
CONFIG_DK_LIBRARY=y

# This example requires more workqueue stack
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

# Enable mcumgr.
CONFIG_MCUMGR=y

# Ensure an MCUboot-compatible binary is generated.
CONFIG_BOOTLOADER_MCUBOOT=y

# Required by the `taskstat` command.
#CONFIG_THREAD_MONITOR=y

# Enable statistics and statistic names.
CONFIG_STATS=y
CONFIG_STATS_NAMES=y

# Enable most core commands.
CONFIG_MCUMGR_CMD_IMG_MGMT=y
CONFIG_MCUMGR_CMD_OS_MGMT=y
CONFIG_MCUMGR_CMD_STAT_MGMT=y

# Enable logging
CONFIG_LOG=n

# Low power
CONFIG_SYS_POWER_MANAGEMENT=y
CONFIG_SYS_POWER_DEEP_SLEEP_STATES=y
CONFIG_SYS_PM_STATE_LOCK=y

So I think I disabled uart and consumption is still high... Do you have an idea what to do?

Best regards,

[Vojislav]

ping, have you think of what could be an issue?

[Heidi]

Hi!

Sorry about the delay! Amanda is currently on vacation so I'll be taking over the case. I will have to talk to some people and get back to you. :)

[Vojislav]

Ok, thanks. Let me know when you have some new information.

[Vojislav]

Heidi any news?

[Heidi]

Hi! I'm sorry, not yet. I'll have someone take a look at it today. 

[Vojislav]

Heidi what is the status of this issue?

[Amanda Hsieh]

Hi Vojislav, 

Sorry for the delay. This case is just reassigned back to me today. 

I need time to check with the internal. Sorry for the inconvenience.

-Amanda H.