acassis commented on code in PR #15795: URL: https://github.com/apache/nuttx/pull/15795#discussion_r1969991230
########## Documentation/components/drivers/wireless/lpwan/sx126x.rst: ########## @@ -0,0 +1,65 @@ +================== +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 Review Comment: Please include the image in the repository, external links can disappear or be moved to other URL -- This is an automated message from the Apache Git Service. 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