Front End Module control with nRF Connect (1.7.0)

RE: Front End Module control with nRF Connect (1.7.0)

Jackie Zamow — Thu, 16 Jun 2022 19:54:34 GMT

I finally solved this issue in v1.9.1! The REAL steps to turn on FEM are as follows, or at least what worked for me:

1) Add the following node to boards/nrf5340dk_nrf5340_cupapp.overlay file AND child_image/hci_rpmsg.overlay:

/ {
nrf_radio_fem: name_of_fem_node {
compatible = "nordic,nrf21540-fem";
tx-en-gpios = <&gpio0 3 GPIO_ACTIVE_HIGH>;
rx-en-gpios = <&gpio0 5 GPIO_ACTIVE_HIGH>;
pdn-gpios = <&gpio0 7 GPIO_ACTIVE_HIGH>;
};
};

2) Add the following file to your project child_image\hci_rpmsg\boards\thingy53_nrf5340_cpunet.conf:

# Copyright (c) 2021 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#

CONFIG_RPMSG_SERVICE=y
CONFIG_RPMSG_SERVICE_MODE_REMOTE=y

CONFIG_HEAP_MEM_POOL_SIZE=8192

CONFIG_MAIN_STACK_SIZE=512
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=512
CONFIG_BT=y
CONFIG_BT_HCI_RAW=y
CONFIG_BT_MAX_CONN=10
CONFIG_BT_CTLR_ASSERT_HANDLER=y
CONFIG_BT_HCI_RAW_RESERVE=1
CONFIG_BT_BUF_CMD_TX_COUNT=10

# Increase maximum data length of PDU supported in the Controller
CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_BT_BUF_ACL_TX_SIZE=251
CONFIG_BT_BUF_ACL_RX_SIZE=502

RE: Front End Module control with nRF Connect (1.7.0)

Jackie Zamow — Wed, 09 Feb 2022 17:46:25 GMT

Hi, I'm still working on this issue, but now in SDK version 1.8.0. Going back to the link you sent, the option that makes the most sense for our application is "Manually create a devicetree overlay file that describes how FEM is connected to the nRF5 SoC in your device." This is because we are not using the specific nRF21540 FEM, we just want to use the 2 wire FEM interface.

What is necessary to manually create the overlay file? Are there any Kconfig flags that I need to mention in my prj.config file to support the new node in my overlay file? Is the child image overlay file supposed to have a new node as well?

RE: Front End Module control with nRF Connect (1.7.0)

Jackie Zamow — Thu, 18 Nov 2021 18:59:46 GMT

So as far as I can tell, there are 4 main steps:

1) Add MPSL support by configuring the interrupts listed here: http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/mpsl/doc/mpsl.html#mpsl-lib

2) Enable MPSL with a config flag in the application core (CONFIG_MPSL = y)

3) Add a node to the application device tree, shown here: http://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_radio_fem.html

4) Add that same node to the child device tree

Right now, I'm struggling with #1. How am I supposed to configure the interrupts to be priority 0? Via a Kconfig flag, or a function call in the application?

RE: Front End Module control with nRF Connect (1.7.0)

Kenneth — Tue, 16 Nov 2021 12:09:50 GMT

[quote user=""]I'm wondering whether the steps listed in the linked documentation are the only steps I need to take to enable this feature.[/quote]

These are all the steps required yes, also see how to do this can be done for a specific BLE sample project (e.g. peripheral UART example):
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/peripheral_uart/README.html#fem-support