Application of FEM chip in ESB

[mingjkl]

My project uses ESB for communication. In our hardware design, nrf5340 + FEM is used. Nrf5340 uses two GPIO link FEM chips to switch between PA mode and LNA mode. May I ask where the switching signals of the two gpios should be added to the ESB driver?

[ovrebekk]

Hi again

Possibly you already noticed this, but in later versions of the nRF Connect SDK we finally have native support for FEM devices in the ESB library

Best regards
Torbjørn

[pauleffect]

Hello. Hate to bother, but just to confirm the ESB part. That also applies to nrf5340?

[ovrebekk]

Hi Paul

If you mean FEM with ESB then this is also supported on the nRF5340, yes.

Best regards
Torbjørn

[ChrisRu]

Good Day,

We build a custom board with nrf5340 & nrf21540, all looks OK for DTS & config and I see that the
esb_fem_for_rx_set() is available and called.
I have the GPIO-TX/RX/PDN + MODE & ANTSEL correct wired.

The ESB is working on the 5340DK board, so I'm sure there is something incoming. But the custom-board not receive anything.
The config for nmp1300 is OK, the 21540 and 5340 have 3v3 volt. I/O is 3v3.

Net-core UART0 disabled in favor for SPI0.

mpsl_fem_enable(); is called before the esb_start_rx()

What do I miss?

*** Booting nRF Connect SDK v2.7.99-cs2-d73b286ff6d9 ***
*** Using Zephyr OS v3.6.99-3d01dcc251bf ***
[00:00:00.002,105] <inf> esb_prx: Enhanced ShockBurst Receiver NetCore
[00:00:00.002,441] <dbg> esb_prx: clocks_start: HF clock started
[00:00:00.002,746] <dbg> esb_prx: esb_fem_init: Fem require receiver setup
[00:00:00.002,746] <dbg> esb_prx: esb_fem_init: Fem require sender setup
[00:00:00.002,838] <inf> esb_prx: ESB initialized
[00:00:00.002,929] <inf> esb_prx: IPC bound complete
[00:00:00.002,929] <inf> esb_prx: Setting up for packet receiption

CONFIG_DT_HAS_NORDIC_NRF21540_FEM_ENABLED=y
CONFIG_DT_HAS_NORDIC_NRF21540_FEM_SPI_ENABLED=y
..
CONFIG_MPSL_FEM_ONLY=y
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 is not set
CONFIG_MPSL_FEM_NRF21540_GPIO_SPI=y
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=y
CONFIG_MPSL_FEM_POWER_MODEL=y
CONFIG_MPSL_FEM_POWER_MODEL_NRF21540_USE_BUILTIN=y
CONFIG_MPSL_FEM_BUILTIN_POWER_MODEL_UPDATE_PERIOD=2000
CONFIG_MPSL_FEM_DEVICE_CONFIG_254=y
CONFIG_MPSL_FEM_INIT_PRIORITY=50
# 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_DEFAULT is not set
CONFIG_MPSL_FEM_LOG_LEVEL=4
..
CONFIG_FEM_AL_LIB=y
CONFIG_FEM=y
CONFIG_NRF21540_FEM=y
..
CONFIG_ESB=y
CONFIG_ESB_MAX_PAYLOAD_LENGTH=32
CONFIG_ESB_TX_FIFO_SIZE=8
CONFIG_ESB_RX_FIFO_SIZE=8
CONFIG_ESB_PIPE_COUNT=8
CONFIG_ESB_RADIO_IRQ_PRIORITY=1
CONFIG_ESB_EVENT_IRQ_PRIORITY=2
..
CONFIG_ESB_SYS_TIMER2=y
CONFIG_ESB_SYS_TIMER_INSTANCE=2

Can you help?

I measure the pins at nrf21540 after esb_start_rx()
RX = 3v
TX = 0v
PDN = 3v
CSN = 3v  <--- that should be 0V as described in the product specs 4446_194 v1.0 / 2020-08-20

Update: Product Spec 4446_194 v1.2 / 2022-01-28, download from the Web, show that the CSN is a non't care (striped out)


so I add a loop in the netcore's main()

bool rxon=false;
   for (;;) {
       if (rxon) {
         esb_stop_rx();
       }
       else {
         esb_start_rx();
       }
       rxon = !rxon;
       LOG_DBG("RX is %s", rxon?"on":"off" );
       k_sleep(K_MSEC(5000));
   }

RTT-Viewer:
[00:00:55.004,821] <dbg> esb_prx: main: RX is off      ----> and the CSN pin is 0V
[00:01:00.004,974] <dbg> esb_prx: main: RX is on     -----> and the CSN pin is 3V

This way never receive anything.

[Susheel Nuguru]

Please create a separate ticket for this as this is different with different custom board and different nrf connect sdk version.

[ChrisRu]

Sure,

Its here now:

119380/fem-nrf21540-soc-5340-esb-receiver-mode-not-working