Application of FEM chip in ESB

RE: Application of FEM chip in ESB

ChrisRu — Thu, 27 Feb 2025 01:47:04 GMT

Sure,

Its here now:

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

RE: Application of FEM chip in ESB

Susheel Nuguru — Wed, 26 Feb 2025 14:19:12 GMT

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

RE: Application of FEM chip in ESB

ChrisRu — Wed, 26 Feb 2025 07:39:12 GMT

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.

RE: Application of FEM chip in ESB

ovrebekk — Wed, 11 Oct 2023 12:46:05 GMT

Hi Paul

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

Best regards
Torbjørn

RE: Application of FEM chip in ESB

pauleffect — Wed, 11 Oct 2023 01:27:31 GMT

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

RE: Application of FEM chip in ESB

ovrebekk — Fri, 17 Mar 2023 13:06:25 GMT

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

RE: Application of FEM chip in ESB

ovrebekk — Mon, 22 Aug 2022 13:32:33 GMT

You welcome 🙂

In the end ESB doesn't properly support FEM devices out of the box, and you would need to do some modifications to the ESB implementation itself to support this.

Best regards
Torbjørn

RE: Application of FEM chip in ESB

mingjkl — Mon, 22 Aug 2022 03:09:22 GMT

Thank you very much for your professional advice.

RE: Application of FEM chip in ESB

ovrebekk — Mon, 15 Aug 2022 13:09:55 GMT

In the ideal world you could just connect the TXREADY and RXREADY events of the radio to GPIO's using the DPPI and GPIOTE peripherals, but the problem then is that the pins would only be set very shortly before the packets are sent or received.

I assume the FEM chip requires this pins to be set a bit before the communication takes place, and possibly they should also be cleared a bit after?

Best regards
Torbjørn