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[Experimental]
This adds a driver for the SX126x (SX1261 and SX1262) LoRa chips.
All functions and definitions are coming directly from the DS SX1261-2 V2.1 datasheet.

Signed-off-by: Kevin Witteveen (MartiniMarter) <[email protected]>
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keever50 committed Feb 24, 2025
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==================
SX126x LoRa driver
==================
**Currently experimental. Changes can happen in the near future**

.. image:: https://www.thethingsnetwork.org/docs/lorawan/transceivers/SX1261.jpg

Short introduction SX126x
=========================
The SX126x is a LoRa chip by Semtech. Sometimes also found in chips with a different name but the same or similar sillicon underneath.
The older variant is the SX127x, even with its higher number. The SX126x series promises to improve the link budget. They also added extra spreading factors.

Userspace API
=============
This driver is controlled as a character device and using IOCTL commands. At the time of writing this 24 February, 2025, there is no common API **yet** for LoRa devices and other RF devices under ``/lpwan``.
Currently this driver is controlled using older and driver specific IOCTL commands.

Basic RF IOCTL
--------------
See ``nuttx/wireless/ioctl.h`` : ``WLIOC_x`` for setting the basic radio parameters such as frequency and power.
Please note that frequency and power may be limited by the lower driver part at board logic.

Driver dedicated IOCTL
----------------------
See ``nuttx/wireless/lpwan/sx126x.h`` : ``SX126XIOC_x`` for the commands.

* The packet type is set using ``SX126XIOC_PACKETTYPESET`` which takes ``sx126x_packet_type_e`` enums. **Currently only LoRa packet type is supported.**

* LoRa modulation and LoRa packets are configured using ``SX126XIOC_LORACONFIGSET`` which takes a pointer to a ``sx126x_lora_config_s`` struct. This struct contains two seperate structures for modulation and packet config. It is recommended to follow the SX126x datasheet at https://www.semtech.com/products/wireless-rf/lora-connect/sx1262 that gives more details about each parameter.

Reading / Writing
-----------------
Reading and writing is done with the ``read`` and ``write`` functions.

* ``write`` directly transmits the given bytes using the IOCTL configured parameters. **Does not support polling or timeout yet.**

* ``read`` takes a pointer to ``sx126x_read_header_s``, which contains information about the received packet. **RSSI and SNR aren't implemented yet**. *Note that packets are always received, even when the CRC (checked using ``.crc_error``) failed.*

Board implementation
====================
The driver can be registered in board logic using ``sx126x_register``, which takes an SPI bus, lower driver and the path.
More information about ``struct sx126x_lower_s`` parameters can be found in detail under ``nuttx/wireless/lpwan/sx126x.h`` : ``struct sx126x_lower_s``.

This driver supports multiple instances using ``dev_number`` found in ``sx126x_lower_s``. This is done so multiple channels of LoRa can work at the same time.

**Do not assign random numbers in get_pa_values. This can damage the device depending on model. Refer to the manual**

Testing
=======
A simple ping-pong test is made to test the device. This code can be used as an example. It is found here https://pastebin.com/71CdKZvm
It takes the following parameters:

* ``-f`` sets frequency in hz. The range is board depended.
* ``-b`` sets the bandwidth in kHz and automatically selects the closest sx126x supported bandwidth.
* ``-s`` sets the spreading factor between 5 and 12.
* ``-p`` sets the power in dBm. The range is board depended. Also PA setting depended.
* ``-t`` perform transmit. Transmit the following bytes.
* ``-r`` perform receive. Receives and print.
* ``-x`` perform transmit and receive. Transmits following bytes and attempts to receives immidiately. To be used with ``-e`` echo
* ``-e`` perform echo. Listen and repeat.

.. image:: https://private-user-images.githubusercontent.com/9679272/415904583-3a979608-6386-4b51-8d0e-acf09d918299.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.6JOsN_-uyyxnlxHg33Bt_WT5DFSO_i-Uh4coi-8xpEc
:alt: Running sx126x -f 869250000 -b 250 -s 10 -p 22 -x "HELLO"

9 changes: 9 additions & 0 deletions drivers/wireless/lpwan/Kconfig
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Expand Up @@ -12,6 +12,15 @@ config LPWAN_SX127X
---help---
This options adds driver support for the Samtech SX127X chip.

config LPWAN_SX126X
bool "SX126X Low Power Long Range transceiver support"
default n
select SPI
---help---
This options adds driver support for the Samtech SX126X chip.

source "drivers/wireless/lpwan/sx126x/Kconfig"

if LPWAN_SX127X

config LPWAN_SX127X_RFFREQ_DEFAULT
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1 change: 1 addition & 0 deletions drivers/wireless/lpwan/Make.defs
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ifeq ($(CONFIG_DRIVERS_LPWAN),y)

include wireless/lpwan/sx127x/Make.defs
include wireless/lpwan/sx126x/Make.defs

endif # CONFIG_DRIVERS_LPWAN
24 changes: 24 additions & 0 deletions drivers/wireless/lpwan/sx126x/CMakeLists.txt
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# ##############################################################################
# drivers/wireless/lpwan/sx126x/CMakeLists.txt
#
# SPDX-License-Identifier: Apache-2.0
#
# Licensed to the Apache Software Foundation (ASF) under one or more contributor
# license agreements. See the NOTICE file distributed with this work for
# additional information regarding copyright ownership. The ASF licenses this
# file to you under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy of
# the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under
# the License.
#
# ##############################################################################
if(CONFIG_LPWAN_SX126X)
target_sources(drivers PRIVATE sx126x.c)
endif()
28 changes: 28 additions & 0 deletions drivers/wireless/lpwan/sx126x/Kconfig
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#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#

if LPWAN_SX126X

config LPWAN_SX126X_RFFREQ_DEFAULT
int "SX126X default RF frequency Hz"
default 869252000

config LPWAN_SX126X_SF_DEFAULT
int "SX126X default spreading factor"
default 10

config LPWAN_SX126X_BW_DEFAULT
int "SX126X default bandwidth kHz"
default 125

config LPWAN_SX126X_CR_DEFAULT
int "SX126X default coding rate"
default 8

config LPWAN_SX126X_MAX_DEVICES
int "SX126X maximum devices"
default 1

endif # DRIVERS_LPWAN
35 changes: 35 additions & 0 deletions drivers/wireless/lpwan/sx126x/Make.defs
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############################################################################
# drivers/wireless/lpwan/sx126x/Make.defs
#
# SPDX-License-Identifier: Apache-2.0
#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership. The
# ASF licenses this file to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance with the
# License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#
############################################################################

# Include SX126X drivers into the build

ifeq ($(CONFIG_LPWAN_SX126X),y)

CSRCS += sx126x.c

# Include SX126X build support

DEPPATH += --dep-path wireless$(DELIM)lpwan$(DELIM)sx126x
VPATH += :wireless$(DELIM)lpwan$(DELIM)sx126x
CFLAGS += ${INCDIR_PREFIX}$(TOPDIR)$(DELIM)drivers$(DELIM)wireless$(DELIM)lpwan$(DELIM)sx126x

endif # CONFIG_LPWAN_SX126X
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