Mathematical logarithm function in nrf9160 M33 core

[Praveen katari]

Hi

I am using nrf9160 device and in my application and have to use mathematical logarithm function in my application.

Could you please help me how I can use mathematical logarithm function and also point me to the libararies if any.

I have included math.h but didnt helped me.

The equation which I want to compute in nrf9160 to calculate temperature:

1/t = (ln(Rt/10000)/3434)+1/25

where t is temperature

Rt is Thermistor resistance

with regards

Praveen K

[Martin Lesund]

Hi Praveen,
What are the configurations set in your application?

I would recommend that you set this in prj.conf:

CONFIG_NEWLIB_LIBC=y
CONFIG_MAIN_STACK_SIZE=2048
CONFIG_FPU=y
CONFIG_SSE=y

Please share any error logs etc. when building if you have any issues.

[Praveen katari]

Hi Martin,

When i use above mentioned configuration in project i am getting below error message.

C:/Git-Repos/Mercury_NRF/hwTests/prj.conf:12: warning: attempt to assign the value 'y' to the undefined symbol SSE
Parsing C:/Git-Repos/Mercury_NRF/hwTests/Kconfig
Loaded configuration 'C:/Git-Repos/Nordic/Master/nrf/zephyr/boards/arm/nrf9160_cl5gm/nrf9160_cl5gmns_defconfig'
Merged configuration 'C:/Git-Repos/Mercury_NRF/hwTests/prj.conf'

error: Aborting due to Kconfig warnings

Thanks

Praveen K

[Martin Lesund]

Please share your full prj.conf file

best regards,
Martin L.

[Praveen katari]

Here is my prj.conf

# General config
#CONFIG_ASSERT=y
#CONFIG_LOG=y
#CONFIG_LOG_DEFAULT_LEVEL=3
#CONFIG_STACK_SENTINEL=y
#CONFIG_CP_LOG_LEVEL_INF=y

#Match operations
#CONFIG_NEWLIB_LIBC=y
CONFIG_FPU=y
#CONFIG_SSE=y

# enable console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

# Segger RTT
CONFIG_USE_SEGGER_RTT=n
CONFIG_RTT_CONSOLE=n
CONFIG_UART_CONSOLE=n
CONFIG_LOG_BACKEND_RTT=n
CONFIG_LOG_BACKEND_UART=n


# enable to use thread names
CONFIG_THREAD_NAME=y

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

# LTE link control
CONFIG_LTE_LINK_CONTROL=y
CONFIG_LTE_AUTO_INIT_AND_CONNECT=n

# BSD library
CONFIG_BSD_LIBRARY=y

# AT host library
CONFIG_AT_HOST_LIBRARY=y
CONFIG_UART_INTERRUPT_DRIVEN=y

# Stacks and heaps
CONFIG_MAIN_STACK_SIZE=2048
CONFIG_HEAP_MEM_POOL_SIZE=1024

# Disable native network stack to save some memory
CONFIG_NET_IPV4=y
CONFIG_NET_IPV6=n
CONFIG_NET_UDP=n
CONFIG_NET_TCP=y

###gpio related###
CONFIG_GPIO=y

###UART CONFIGURATION###
#Enables serial driver
CONFIG_SERIAL=y

#Needed for enabling ISRs
CONFIG_UART_INTERRUPT_DRIVEN=y

#UART RAM buffer allocation, see TXD.MAXCNT on nRF9160
CONFIG_UART_0_NRF_TX_BUFFER_SIZE=1024
CONFIG_UART_1_NRF_TX_BUFFER_SIZE=1024

###power management###
CONFIG_DEVICE_POWER_MANAGEMENT=y

###RTOS###
#enables polling
CONFIG_POLL=y

#PP---???
#CONFIG_DYNAMIC_OBJECTS=y

#enables ring buffer
CONFIG_RING_BUFFER=y

#this macro enabled for u8_t to work
CONFIG_DEPRECATED_ZEPHYR_INT_TYPES=y


CONFIG_NRFX_UARTE=y
CONFIG_NRFX_UARTE0=y
CONFIG_NRFX_UARTE1=y


CONFIG_ADC=y
#CONFIG_ADC_0=y
#CONFIG_ADC_NRFX_SAADC=y

#SPI
CONFIG_SPI=y
CONFIG_SPI_3=y
CONFIG_SPI_NRFX=y
#CONFIG_MAIN_STACK_SIZE=4096

#I2C
CONFIG_I2C=y
CONFIG_I2C_NRFX=y
CONFIG_I2C_2=y

[Martin Lesund]

Remove the CONFIG_SSE, but keep the configurations:

CONFIG_NEWLIB_LIBC=y
CONFIG_MAIN_STACK_SIZE=2048
CONFIG_FPU=y

That should work.