Disabling serial interface from nrf-9160: Cloud_Client for PSM current measurements

[harisahmed]

Hi,

I have been able to use the NRF-9160: Cloud_Client sample for sending data to my AWS IoT MQTT broker on PSM mode from my Thingy91 with a CLOUD_MESSAGE_PUBLICATION_INTERVAL set to 10. The code works fine and I can see the strings being received on AWS IoT console every ten seconds.

Now, I want to disable serial interface between the Thingy91 and the computer to measure actual current consumption on PSM mode. For this I set following configuration in my Cloud Client prj.conf file:

#
# Copyright (c) 2020 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
#

# General config
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_RESET_ON_FATAL_ERROR=n
# CONFIG_NCS_SAMPLES_DEFAULTS=y

# Log level
# For more verbose and detailed log output, set the log level to
# CONFIG_CLOUD_CLIENT_LOG_LEVEL_DBG=y instead.
CONFIG_SERIAL=n
CONFIG_LOG=n
# CONFIG_LOG_IMMEDIATE=y
# CONFIG_CLOUD_CLIENT_LOG_LEVEL_DBG=y
# CONFIG_CLOUD_CLIENT_LOG_LEVEL_INF=y

# Network
CONFIG_NETWORKING=y
CONFIG_NET_NATIVE=n
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_OFFLOAD=y

# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_NETWORK_MODE_NBIOT=y
CONFIG_LTE_LEGACY_PCO_MODE=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n
CONFIG_POWER_SAVING_MODE_ENABLE=y

# BSD library
CONFIG_BSD_LIBRARY=y

# DK
CONFIG_DK_LIBRARY=y

# AT commands interface
CONFIG_UART_INTERRUPT_DRIVEN=n
CONFIG_AT_HOST_LIBRARY=y

# Generic cloud API
CONFIG_CLOUD_API=y
CONFIG_CLOUD_PUBLICATION_SEQUENTIAL=y

# nRF Cloud
CONFIG_NRF_CLOUD=n

# AWS IoT library
CONFIG_AWS_IOT=y
CONFIG_AWS_IOT_PORT=8883
CONFIG_AWS_IOT_CLIENT_ID_STATIC=""
CONFIG_AWS_IOT_BROKER_HOST_NAME=""
CONFIG_AWS_IOT_SEC_TAG=
CONFIG_AWS_IOT_APP_SUBSCRIPTION_LIST_COUNT=2
CONFIG_AWS_IOT_TOPIC_UPDATE_DELTA_SUBSCRIBE=y
CONFIG_AWS_IOT_CONNECTION_POLL_THREAD=y

# Heap and stacks
# Extended memory heap size needed for encoding nRF Cloud messages to JSON
CONFIG_HEAP_MEM_POOL_SIZE=8192
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

# Modem information
CONFIG_MODEM_INFO=y

Also, I added CONFIG_SERIAL=n in nrf-9160:SPM sample as well.

But with this Cloud Client configuration my code doesn't run and I am not sure what is the problem as I can't debug it without serial interface. The same configuration works when I set the following settings to true:

CONFIG_SERIAL=y
CONFIG_LOG=y
CONFIG_LOG_IMMEDIATE=y
CONFIG_CLOUD_CLIENT_LOG_LEVEL_DBG=y
CONFIG_CLOUD_CLIENT_LOG_LEVEL_INF=y

So I am sure that my other settings are correct and only disabling serial interface makes my code block at some point and I am not sure where.

Is there some setting here which can block the execution of code if the serial is disabled? Can someone please help me debug this issue? I am attaching the full code as well. if that helps4137.cloud_client-psm.rar

Thank you.

Regards,

Haris Ahmed

[harisahmed]

I did try with 1.4.0 as well. I didn't see much of a difference.

Regards,

Haris Ahmed

[JONATHAN LL]

What modem version are you using? 

It is recommended to update to latest modem version. 

Are you sure you are getting a PSM from the network? if not then the current draw will be higher. You can check by trying the XMONITOR AT command. 

Regards,
Jonathan

[harisahmed]

I am on the latest modem version and I am able to switch on PSM as well because with logs enabled I see PSM timers received from the network.

I have managed to reach at current consumption of 6 micro amps in Cloud Client (v1.4.0) sample by doing some modifications.

I copied over all the configurations of modem and low power modes from the UDP sample. Also, for me staying connected with AWS MQTT server was not a big deal so I decided to disconnect from the server after sending a value and this seems to do the trick. After waiting for a few seconds after disconnection current goes to 6 micro amps with no major fluctuations. Before sending the next value I can reconnect again. I am attaching the modified sample code as it might help someone else

Thank you.

Regards,

Haris Ahmed

cloud_client.rar