I use nrf9160 to develop a product for customers. The modem is also set to PSM and the log is turned off. However, I find that when the modem is connected to the Internet, it needs to use UART0. When I turn off UART0 or set it to low power consumption, the system will crash. Why? Why does the communication between modem and 9160 need UART0? Even if I have closed the log.
This is my proj.conf file:
#
# Copyright (c) 2019 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
#
# General config
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_ASSERT=y
CONFIG_REBOOT=y
CONFIG_GPIO=y
CONFIG_TRUSTED_EXECUTION_NONSECURE=y
# Log
CONFIG_LOG=n
CONFIG_LOG_IMMEDIATE=y
CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_DEFAULT_LEVEL=4
CONFIG_LOG_MODE_OVERFLOW=y
CONFIG_LOG_BACKEND_RTT_MODE_DROP=y
CONFIG_LOG_BACKEND_SHOW_COLOR=n
CONFIG_LOG_BACKEND_FORMAT_TIMESTAMP=n
# watch dog
CONFIG_WATCHDOG=y
CONFIG_WATCHDOG_TIMEOUT_MSEC=10000
# Modem info
CONFIG_MODEM_INFO=y
# BSD library
CONFIG_BSD_LIBRARY=y
CONFIG_BSD_LIBRARY_TRACE_ENABLED=n
# Flash
CONFIG_FLASH=y
CONFIG_IMG_ERASE_PROGRESSIVELY=y
# NVS
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_NVS=y
CONFIG_NVS_LOG_LEVEL_DBG=y
CONFIG_MPU_ALLOW_FLASH_WRITE=y
# GPS
CONFIG_NRF9160_GPS=y
#CONFIG_GPS_USE_SIM=y
CONFIG_GPS_USE_EXTERNAL=y
CONFIG_GPS_DEV_NAME="NRF9160_GPS"
CONFIG_GPS_CONTROL_PSM_ENABLE_ON_START=y
CONFIG_GPS_CONTROL_FIRST_FIX_CHECK_DELAY=10
CONFIG_GPS_CONTROL_FIX_CHECK_INTERVAL=30
CONFIG_GPS_CONTROL_FIX_TRY_TIME=360
CONFIG_GPS_CONTROL_PSM_DISABLE_ON_STOP=n
# AT_CMD
CONFIG_AT_HOST_LIBRARY=y
CONFIG_UART_INTERRUPT_DRIVEN=y
# Console
CONFIG_CONSOLE_SUBSYS=n
CONFIG_CONSOLE_HANDLER=n
CONFIG_CONSOLE_GETCHAR=n
CONFIG_CONSOLE=n
CONFIG_RTT_CONSOLE=y
CONFIG_UART_CONSOLE=n
# Enable SUPL client support AGPS
CONFIG_SUPL_CLIENT_LIB=n
# Network
CONFIG_NETWORKING=y
CONFIG_NET_NATIVE=n
CONFIG_NET_SOCKETS_OFFLOAD=y
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_POSIX_NAMES=y
# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n
CONFIG_LTE_NETWORK_USE_FALLBACK=y
CONFIG_LTE_NETWORK_TIMEOUT=60
CONFIG_LTE_NETWORK_MODE_LTE_M_GPS=n
CONFIG_LTE_NETWORK_MODE_NBIOT_GPS=y
CONFIG_LTE_LEGACY_PCO_MODE=y
# PSM
CONFIG_LTE_PSM_ENABLE=y
# Set Periodic-TAU timer to 10 minutes and Active-Time to 20 seconds.
CONFIG_LTE_PSM_REQ_RPTAU="10101010"
CONFIG_LTE_PSM_REQ_RAT="00001010"
# eDRX
CONFIG_LTE_EDRX_ENABLE=n
CONFIG_LTE_EDRX_REQ_VALUE="1001"
# RAI
CONFIG_LTE_RAI_ENABLE=n
# MQTT
CONFIG_MQTT_LIB=y
CONFIG_MQTT_LIB_TLS=n
CONFIG_MQTT_KEEPALIVE=300
CONFIG_MQTT_PUB_TOPIC="device/auri/pushdata"
CONFIG_MQTT_SUB_TOPIC="device/auri/"
CONFIG_MQTT_CLIENT_ID="my-client-id"
CONFIG_MQTT_USER_NAME="admin123"
CONFIG_MQTT_PASSWORD="admin123"
CONFIG_MQTT_DOMESTIC_BROKER_HOSTNAME="47.107.51.89"
CONFIG_MQTT_DOMESTIC_BROKER_PORT=1883
CONFIG_MQTT_FOREIGN_BROKER_HOSTNAME="18.135.53.53"
CONFIG_MQTT_FOREIGN_BROKER_PORT=1883
# Library for buttons and LEDs
CONFIG_DK_LIBRARY=y
CONFIG_DK_LIBRARY_INVERT_LEDS=n
# Heap and stacks
CONFIG_HEAP_MEM_POOL_SIZE=16384
CONFIG_MAIN_STACK_SIZE=8192
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_HW_STACK_PROTECTION=y
# SPI
CONFIG_SPI=y
CONFIG_SPI_NRFX=y
CONFIG_SPI_2=n
CONFIG_SPI_2_NRF_SPIM=n
CONFIG_SPI_3=y
CONFIG_SPI_3_NRF_SPIM=y
# I2C
CONFIG_I2C=y
CONFIG_I2C_NRFX=y
CONFIG_I2C_1=y
CONFIG_I2C_1_NRF_TWIM=y
CONFIG_I2C_2=n
CONFIG_I2C_2_NRF_TWIM=n
CONFIG_I2C_INIT_PRIORITY=60
# UART
CONFIG_SERIAL=y
CONFIG_UART_2_NRF_UARTE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
# ANIMATION
CONFIG_ANIMATION_SUPPORT=y
# PPG
CONFIG_PPG_SUPPORT=y
# IMU
CONFIG_IMU_SUPPORT=y
CONFIG_FALL_DETECT_SUPPORT=n
# WIFI
CONFIG_WIFI=n
# TP
CONFIG_TOUCH_SUPPORT=y
# AUDIO
CONFIG_AUDIO_SUPPORT=n
# Data Sync
CONFIG_SYNC_SUPPORT=y
# Temperature
CONFIG_TEMP_SUPPORT=y
# CRC Check
CONFIG_CRC_SUPPORT=y
# DEVICE POWER MANAGEMENT
CONFIG_DEVICE_POWER_MANAGEMENT=y
# Download client
CONFIG_DOWNLOAD_CLIENT=y
CONFIG_DOWNLOAD_CLIENT_TLS=y
CONFIG_DOWNLOAD_CLIENT_STACK_SIZE=4096
# DATA UPDATE
CONFIG_DATA_DOWNLOAD_SUPPORT=y
CONFIG_DATA_DOWNLOAD_HOST_HK="aug-fm-files-hk.oss-cn-hongkong.aliyuncs.com"
CONFIG_DATA_DOWNLOAD_HOST_CN="aug-fm-files-cn.oss-cn-shenzhen.aliyuncs.com"
# IMG
CONFIG_IMG_DATA_UPDATE=y
CONFIG_IMG_DATA_DOWNLOAD_FILE="E2/e2_img.bin"
# FONT
CONFIG_FONT_DATA_UPDATE=y
CONFIG_FONT_DATA_DOWNLOAD_FILE="E2/e2_font.bin"
# PPG
CONFIG_PPG_DATA_UPDATE=y
CONFIG_PPG_DATA_DOWNLOAD_FILE="E2/e2_ppg.bin"
# fota download
#CONFIG_FOTA_DOWNLOAD=y
#CONFIG_FOTA_DOWNLOAD_PROGRESS_EVT=y
#CONFIG_FOTA_DOWNLOAD_HOST_HK="aug-fm-files-hk.oss-cn-hongkong.aliyuncs.com"
#CONFIG_FOTA_DOWNLOAD_HOST_CN="aug-fm-files-cn.oss-cn-shenzhen.aliyuncs.com"
#CONFIG_FOTA_DOWNLOAD_FILE="E2/e2_update.bin"
#CONFIG_APPLICATION_VERSION=1
# Image manager
#CONFIG_IMG_MANAGER=y
#CONFIG_FLASH=y
#CONFIG_IMG_ERASE_PROGRESSIVELY=y
# DFU Target
#CONFIG_DFU_TARGET=y
# Modem key management
#CONFIG_MODEM_KEY_MGMT=y
# Application Upgrade support
#CONFIG_BOOTLOADER_MCUBOOT=y
n
