146 lines
4.9 KiB
YAML
146 lines
4.9 KiB
YAML
# Copyright (c) 2020, 2021 Nordic Semiconductor ASA
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# SPDX-License-Identifier: Apache-2.0
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description: |
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This is a representation of the nRF21540 Radio Front-End module.
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See the "nordic,nrf21540-fem-spi" binding to configure the SPI
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interface. The SPI interface should be configured as a child node
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of the SPI bus you have connected to the FEM. Then you "connect"
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the FEM and SPI configurations using the spi-if property.
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Here is an example nRF21540 configuration with a SPI interface
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selected, using the SPIM0 peripheral found on several nRF5 SoCs:
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&spi0 {
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compatible = "nordic,nrf-spim";
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status = "okay";
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cs-gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;
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/* ... MISO/MOSI/SCK pin configuration goes here ... */
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my_spi_if: nrf21540-spi@0 {
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compatible = "nordic,nrf21540-fem-spi";
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reg = <0>;
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spi-max-frequency = <8000000>;
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};
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};
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nrf_radio_fem: nrf21540 {
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compatible = "nordic,nrf21540-fem";
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tx-en-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
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rx-en-gpios = <&gpio0 5 GPIO_ACTIVE_HIGH>;
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spi-if = <&my_spi_if>;
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pdn-gpios = <...>;
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ant-sel-gpios = <...>;
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mode-gpios = <...>;
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/* ... other nRF21540 properties go here ... */
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};
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&radio {
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fem = <&nrf_radio_fem>;
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};
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In the above example, the nRF21540 is configured for use with:
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- TX_EN on P0.2 (from 'tx-en-gpios')
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- RX_EN on P0.5 (from 'rx-en-gpios')
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- SPI communication via SPIM0 (the bus, or parent node, of
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the 'my_spi_if' node
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- CSN on P1.3 (from index 0 in the bus node's 'cs-gpios' property)
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You must perform any additional required SPI pin configuration
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(nRF21540 MISO, MOSI, and SCK pins) within the SPI bus node
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('spi0' in the above example). See your SPI node's binding for
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details on these pin mux properties. You can use any SPI node
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available in your SoC's devicetree.
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Configure any other nRF21540 pins as needed using 'pdn-gpios',
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'ant-sel-gpios', and 'mode-gpios' properties. If unsure about the
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format, use 'tx-en-gpios' as an example.
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Finally, the nRF5 SoC's radio peripheral is set up for use with
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the nRF21540 via the 'fem' property in the 'radio' node.
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compatible: "nordic,nrf21540-fem"
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include: base.yaml
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properties:
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tx-en-gpios:
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type: phandle-array
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required: false
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description: |
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GPIO of the SOC controlling TX_EN pin of the nRF21540
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rx-en-gpios:
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type: phandle-array
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required: false
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description: |
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GPIO of the SOC controlling RX_EN pin of the nRF21540
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pdn-gpios:
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type: phandle-array
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required: false
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description: |
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GPIO of the SOC controlling PDN pin of the nRF21540
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ant-sel-gpios:
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type: phandle-array
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required: false
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description: |
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GPIO of the SOC controlling ANT-SEL pin of the nRF21540
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mode-gpios:
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type: phandle-array
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required: false
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description: |
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GPIO of the SOC controlling MODE pin of the nRF21540
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spi-if:
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type: phandle
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required: false
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description: |
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Reference to the nordic,nrf21540-fem-spi SPI bus interface.
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This must be present to support SPI control of the FEM.
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tx-en-settle-time-us:
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type: int
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default: 11
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description: |
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Settling time in microseconds from state PG to TX.
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Default value is based on Table 6 of the nRF21540 Product
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Specification (v1.0), and can be overridden for tuned
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configurations.
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rx-en-settle-time-us:
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type: int
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default: 11
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description: |
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Settling time in microseconds from state PG to RX.
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Default value is based on Table 6 of the nRF21540 Product
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Specification (v1.0), and can be overridden for tuned
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configurations.
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pdn-settle-time-us:
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type: int
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default: 18
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description: |
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Settling time in microseconds from state PD to PG.
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Default value is based on Table 6 of the nRF21540 Product
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Specification (v1.0), and can be overridden for tuned
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configurations.
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trx-hold-time-us:
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type: int
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default: 3
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description: |
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Power-off time in microseconds when changing from RX or TX to PG.
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Default value is based on Table 6 of the nRF21540 Product
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Specification (v1.0), and can be overridden for tuned
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configurations.
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supply-voltage-mv:
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type: int
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required: false
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description: |
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nRF21540 supply voltage in mV.
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This is used if compensation for nRF21540 supply voltage is supported
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by software.
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