NXP M.2 IEEE 802.15.4 SPI RCP Shield

Overview

This Zephyr shield exposes an IEEE 802.15.4 Radio Co-Processor (RCP) over a SPI transport, using an NXP M.2 module connected to the host platform through its M.2 interface slot. The RCP runs the 802.15.4 radio and communicates with the host using the Spinel protocol carried over an HDLC-framed SPI link (spi,hdlc-rcp-if). This makes the shield suitable for OpenThread host applications such as the OpenThread Border Router, where the host runs the OpenThread stack and the M.2 module provides the 802.15.4 radio.

The shield is tested with the following M.2 modules:

Embedded Artist 2EL module - uses Murata 2EL radio module with NXP IW612 chipset
Embedded Artist 2LL module - uses Murata 2LL radio module with NXP IW610 chipset

More information about the supported chipsets, radio modules and M.2 modules can be found in the links below:

Requirements

To use the shield, the requirements below must be satisfied.

An M.2 module with a SPI RCP interface and an NXP IW612 or IW610 SoC.
A host platform with a compatible M.2 interface slot and a free SPI controller exposing SCK, SDI, SDO, a chip-select GPIO and an interrupt GPIO.
The board overlay must enable the host SPI controller (for example &lpspi4 on the MIMXRT1060-EVK Rev-C) with cs-gpios and pinctrl, and instantiate the spi,hdlc-rcp-if device node with its int-gpios.

Integration Platform

This shield is validated and tested for use with the host platform listed below. While the shield can be used with other host platforms, other combinations are not actively tested or validated.

MIMXRT1060-EVK Rev-C (mimxrt1060_evk@C/mimxrt1062/qspi).

Fetch Binary Blobs

The M.2 module requires fetching binary blobs, using the following command:

west blobs fetch hal_nxp

Programming

Use the following shield name with --shield <option> when you invoke west build.

nxp_m2_2el_2ll_ieee802154: For IEEE 802.15.4 SPI RCP with NXP IW612 (Murata 2EL) or IW610 (Murata 2LL) M.2 modules.

This single shield supports both M.2 modules:

IW612 (Murata 2EL) module
IW610 (Murata 2LL) module

The choice of module is made through the module-specific configuration fragment passed on the command line (mimxrt1060_evkc_iw612.conf for IW612 or mimxrt1060_evkc_iw610.conf for IW610). The shield overlay and pin assignments are identical for both modules.

The OpenThread Border Router is a Wi-Fi + Thread application. It combines the Wi-Fi/Bluetooth M.2 shield (nxp_m2_2ll_wifi_bt) with this 802.15.4 RCP shield (nxp_m2_2el_2ll_ieee802154), and requires the RCP host overlay plus the board-specific and module-specific configuration fragments.

To build for the MIMXRT1060-EVK Rev-C with an IW612 (Murata 2EL) module:

west build -p -b mimxrt1060_evk@C/mimxrt1062/qspi \
    -d build_mimxrt1060_evk/border_router_iw612 \
    --shield "nxp_m2_2ll_wifi_bt nxp_m2_2el_2ll_ieee802154" \
    zephyr/samples/net/openthread/border_router \
    -- -DEXTRA_CONF_FILE="overlay-ot-rcp-host-wifi-nxp.conf \
    boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evk_mimxrt1062_qspi_C.conf \
    boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evkc_iw612.conf"

To build for the MIMXRT1060-EVK Rev-C with an IW610 (Murata 2LL) module, use the IW610 module fragment instead:

west build -p -b mimxrt1060_evk@C/mimxrt1062/qspi \
    -d build_mimxrt1060_evk/border_router_iw610 \
    --shield "nxp_m2_2ll_wifi_bt nxp_m2_2el_2ll_ieee802154" \
    zephyr/samples/net/openthread/border_router \
    -- -DEXTRA_CONF_FILE="overlay-ot-rcp-host-wifi-nxp.conf \
    boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evk_mimxrt1062_qspi_C.conf \
    boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evkc_iw610.conf"

The configuration fragments passed via EXTRA_CONF_FILE are applied in order:

overlay-ot-rcp-host-wifi-nxp.conf: base OpenThread RCP host + NXP Wi-Fi configuration (originally tuned for RW610).
boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evk_mimxrt1062_qspi_C.conf: RT1060 EVKC overrides for the M.2 IW612/IW610 RCP setup (disables RW610 specific options, sizes heap and network buffers, sets logging).
boards/mimxrt1060_evk_mimxrt1062_qspi_C/mimxrt1060_evkc_iw612.conf (or mimxrt1060_evkc_iw610.conf): module-specific settings selecting the IW612 or IW610 module respectively.

Note

The shield selects the HDLC RCP SPI interface and enables OpenThread L2 by default. The host SPI controller pinmux and GPIO assignments are provided by the board-specific overlay in boards/<board>.overlay.

Pin Assignments (MIMXRT1060-EVK Rev-C)

On the MIMXRT1060-EVK Rev-C the RCP link uses LPSPI4 with the following signals:

Signal	Pin	Notes
SPI SDI	GPIO_B0_01	LPSPI4 SDI
SPI SDO	GPIO_B0_02	LPSPI4 SDO
SPI SCK	GPIO_B0_03	LPSPI4 SCK
SPI CS	GPIO_B0_00 (GPIO2.00)	Chip select, active low
SPI INT	GPIO_B0_04 (GPIO2.04)	RCP host interrupt, active low

Note

The board overlay disables the LCD interface (&lcdif) to free the GPIO_B0_xx pins used by LPSPI4.