Questions about testing the coap_client and coap_server demo while using openthread network

[hyman]

Hello,

        I Use the nRF52840DK and nRF21540DK to test the coap_client and coap_server demo ,SDK is ncs-2.2.0 ,IDE is VS Code .

        1. I want to extend the communication distance, so I use the nRF21540DK ,when compile the program ,the board which I selected is nrf21540dk_nrf52840 ,when finished compile ,I check the .config file in build/zephyr folder. and the config item was all add ,so I think my operation is OK.

# CONFIG_MPSL_FEM_ONLY is not set
CONFIG_MPSL_FEM_ANY_SUPPORT=y
CONFIG_MPSL_FEM_NRF21540_GPIO_SUPPORT=y
CONFIG_MPSL_FEM_NRF21540_GPIO_SPI_SUPPORT=y
CONFIG_MPSL_FEM_NCS_SUPPORTED_FEM_USED=y
CONFIG_MPSL_FEM_API_AVAILABLE=y
CONFIG_MPSL_FEM=y
CONFIG_MPSL_FEM_NRF21540_GPIO=y
# CONFIG_MPSL_FEM_NRF21540_GPIO_SPI is not set
CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=10
CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB_POUTA=20
CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB_POUTB=10
CONFIG_MPSL_FEM_NRF21540_RX_GAIN_DB=13
# CONFIG_MPSL_FEM_NRF21540_RUNTIME_PA_GAIN_CONTROL is not set
# CONFIG_MPSL_FEM_POWER_MODEL is not set
CONFIG_MPSL_FEM_DEVICE_CONFIG_254=y
# CONFIG_MPSL_FEM_LOG_LEVEL_OFF is not set
# CONFIG_MPSL_FEM_LOG_LEVEL_ERR is not set
# CONFIG_MPSL_FEM_LOG_LEVEL_WRN is not set
# CONFIG_MPSL_FEM_LOG_LEVEL_INF is not set
CONFIG_MPSL_FEM_LOG_LEVEL_DBG=y
CONFIG_MPSL_FEM_LOG_LEVEL=4
CONFIG_MPSL_THREAD_COOP_PRIO=0
CONFIG_MPSL_WORK_STACK_SIZE=1024
CONFIG_MPSL_TIMESLOT_SESSION_COUNT=0
# CONFIG_MPSL_ASSERT_HANDLER is not set
# CONFIG_MPSL_LOG_LEVEL_OFF is not set
# CONFIG_MPSL_LOG_LEVEL_ERR is not set
# CONFIG_MPSL_LOG_LEVEL_WRN is not set
# CONFIG_MPSL_LOG_LEVEL_INF is not set
CONFIG_MPSL_LOG_LEVEL_DBG=y
CONFIG_MPSL_LOG_LEVEL=4

        To see the difference in transmission power ,I Use the nrf802154_sniffer and Wireshark to capture the packets of nRF52840DK and nRF21540DK ,I found the RSS display on Wireshark no difference ，the captured RSS are all -18dbm. 

        I tried to modify the tx power in conf as below ,but the captured RSS as the same .

CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=20

        My question is that why captured RSS is the same ?

        I found thers is no log in nRF21540 module , What should I do to verify that nRF21540 really works ?

        2、When I captured the CoAP packets ,I found unique send Only send packet once ，but mesh multicast send will send packet four times , Wireshark show that three times are Retransmission ,in the four times transmission ,some transmission's RSS is -18dbm ,and some is -65dbm .as below .

        My question is that the feature of four transmissions while multicast ,Does this feature belong to the coap protocol or the thread protocol or developed in user application ?

        Why the RSS of four transmission is not the same ?

        

        Best Regards,

        Hyman

[Jørgen Holmefjord]

hyman said:

I have seen the the retransmit messages while using UDP multicast .I want to know how to disable the characteristic of retransmission while using UDP multicast .

See this answer.

hyman said:

When I test coap_client and coap_server demo ,I use nRF21540DK(select nRF21540DK_nRF52840 ) and nRF52840DK((select nRF52840DK_nRF52840 ) ),I want to evaluate nRF21540 ,but I can't see any log about nRF21540. I put the two DK very close to sniffer board (<5cm),I see the RSS is the same ,when I modify the conf of  nRF21540DK(select nRF21540DK_nRF52840 )  CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB from 10 to 20 ,I found the RSS also the same .so I don't think it works properly.

        Colud you help me how to let the nRF21540DK work properly？

There have been some issues with this before, which is why I asked you to try with nRF Connect SDK v2.3.0. You may also try to include this fix if you do not want to upgrade the version.

[hyman]

Hi,

        I have download the NCS SDK v2.3.0 ,but I found the modification on github was not commit to the SDK v2.3.0 ,then I include the patch Manually . The test result is also incorrect .The RSSI is very weak ,nRF21540DK not work properly .

        Colud you help me how to let the nRF21540DK work properly？

        Thanks,

        Best Regards,

        Hyman