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nordic,nrf21540-fem
Vendor: Nordic Semiconductor
Description
This is a representation of the nRF21540 Radio Front-End module.
See the "nordic,nrf21540-fem-spi" binding to configure the SPI
interface. The SPI interface should be configured as a child node
of the SPI bus you have connected to the FEM. Then you "connect"
the FEM and SPI configurations using the spi-if property.
Here is an example nRF21540 configuration with a SPI interface
selected, using the SPIM0 peripheral found on several nRF5 SoCs:
&spi0 {
compatible = "nordic,nrf-spim";
status = "okay";
cs-gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;
/* ... MISO/MOSI/SCK pin configuration goes here ... */
my_spi_if: nrf21540-spi@0 {
compatible = "nordic,nrf21540-fem-spi";
reg = <0>;
spi-max-frequency = <8000000>;
};
};
nrf_radio_fem: nrf21540 {
compatible = "nordic,nrf21540-fem";
tx-en-gpios = <&gpio0 2 GPIO_ACTIVE_HIGH>;
rx-en-gpios = <&gpio0 5 GPIO_ACTIVE_HIGH>;
spi-if = <&my_spi_if>;
pdn-gpios = <...>;
ant-sel-gpios = <...>;
mode-gpios = <...>;
/* ... other nRF21540 properties go here ... */
};
&radio {
fem = <&nrf_radio_fem>;
};
In the above example, the nRF21540 is configured for use with:
- TX_EN on P0.2 (from 'tx-en-gpios')
- RX_EN on P0.5 (from 'rx-en-gpios')
- SPI communication via SPIM0 (the bus, or parent node, of
the 'my_spi_if' node
- CSN on P1.3 (from index 0 in the bus node's 'cs-gpios' property)
You must perform any additional required SPI pin configuration
(nRF21540 MISO, MOSI, and SCK pins) within the SPI bus node
('spi0' in the above example). See your SPI node's binding for
details on these pin mux properties. You can use any SPI node
available in your SoC's devicetree.
Configure any other nRF21540 pins as needed using 'pdn-gpios',
'ant-sel-gpios', and 'mode-gpios' properties. If unsure about the
format, use 'tx-en-gpios' as an example.
Finally, the nRF5 SoC's radio peripheral is set up for use with
the nRF21540 via the 'fem' property in the 'radio' node.
Properties
Properties not inherited from the base binding file.
Name |
Type |
Details |
|---|---|---|
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GPIO of the SOC controlling TX_EN pin of the nRF21540
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GPIO of the SOC controlling RX_EN pin of the nRF21540
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GPIO of the SOC controlling PDN pin of the nRF21540
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GPIO of the SOC controlling ANT-SEL pin of the nRF21540
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GPIO of the SOC controlling MODE pin of the nRF21540
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Reference to the nordic,nrf21540-fem-spi SPI bus interface.
This must be present to support SPI control of the FEM.
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Settling time in microseconds from state PG to TX.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: |
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Settling time in microseconds from state PG to RX.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: |
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Settling time in microseconds from state PD to PG.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: |
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Power-off time in microseconds when changing from RX or TX to PG.
Default value is based on Table 6 of the nRF21540 Product
Specification (v1.0), and can be overridden for tuned
configurations.
Default value: |
Deprecated properties not inherited from the base binding file.
(None)
Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “nordic,nrf21540-fem” compatible.
Name |
Type |
Details |
|---|---|---|
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indicates the operational status of a device
Legal values: See Important properties for more information. |
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compatible strings
This property is required. See Important properties for more information. |
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register space
See Important properties for more information. |
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name of each register space
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interrupts for device
See Important properties for more information. |
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extended interrupt specifier for device
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name of each interrupt
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phandle to interrupt controller node
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Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. |
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Clock gate information
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name of each clock
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number of address cells in reg property
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number of size cells in reg property
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DMA channels specifiers
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Provided names of DMA channel specifiers
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IO channels specifiers
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Provided names of IO channel specifiers
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mailbox / IPM channels specifiers
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Provided names of mailbox / IPM channel specifiers
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Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
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Power domain the device belongs to.
The device will be notified when the power domain it belongs to is either
suspended or resumed.
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