124 lines
3.9 KiB
Markdown
124 lines
3.9 KiB
Markdown
# ESP32 LoRa (SX127*)
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Provides SPI driver for SX1276/SX1278 LoRa radio
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## Install
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Designed to be used as an `esp-idf component`. Suggested usage is with `git submodule`
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```
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git submodule add https://gitlab.com/morganrallen/esp32-lora.git components/esp32-lora/
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git submodule init
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git submodule update
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```
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## Configure
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Uses built in KConfig for configuration.
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Run `make menuconfig` and find config under `Component config` -> `LORA32`.
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Defaults targeted to TTGO LoRa OLED boards.
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## Use
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This is the most basic usage. Setting up the LoRa instance, setting it's receive handler, running init then sending a message.
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```
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#include <stdio.h>
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#include <string.h>
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#include "esp32-lora.h";
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lora32_cfg_t lora;
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static void handle_lora_receive(uint8_t size) {
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char *message = malloc(size+1);
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lora32_read_data(&lora, message);
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// ensure null termination
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message[size] = '\0';
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printf("msg: %s\n", message);
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}
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void app_main() {
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lora = lora32_create();
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lora.receive = &handle_lora_receive;
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lora32_init(&lora);
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lora32_send(&lora, "Hello, LoRa", 11);
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}
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```
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## API
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### `static lora32_cfg_t lora32_create()`
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Creates a new LoRa instance.
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### `uint8_t lora32_init(lora32_cfg_t *config)`
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Initialized LoRa instance. This configures GPIOs, SPI, LoRa radio and receive handlers.
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Returns 1 on success.
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### `void lora32_set_bandwidth(lora32_cfg_t *lora, enum bandwidth bw)`
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Set operating bandwidth. Accepts enum bandwidth
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`B78`, `B104`, `B156`, `B208`, `B3125`, `B417`, `B625`, `B125`, `B250`, `B500` or `0`-`9`
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### `void lora32_set_coding_rate(lora32_cfg_t *lora, uint8_t d)`
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Set `Coding Rate`.
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Accepts `5`-`8`.
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### `uint8_t lora32_data_available(lora32_cfg_t *lora)`
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Returns number of bytes available in FIFO buffer.
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### `void lora32_send(lora32_cfg_t *config, uint8_t *data, uint8_t len)`
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Transmits data over the LoRa radio. Puts `DIO0` into `TXDONE` mode.
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### `void lora32_set_spreadfactor(lora32_cfg_t *lora, uint8_t factor)`
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Sets LoRa Spread Factor.
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Accepts `6`-`12`.
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### `double lora32_calc_datarate(lora32_cfg_t *lora);`
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Returns data rate in Bits Per Second (bps) for given `lora32_cfg_t` configuration.
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### `void lora32_dump_regs(lora32_cfg_t *lora)`
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Dumps all registers from SX1276.
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### `void lora32_read_data(lora32_cfg_t *lora, uint8_t *data)`
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Reads data out of FIFO buffer. This would typically be called after the callback `received` is triggered.
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### `void lora32_enable_continuous_rx(lora32_cfg_t *lora)`
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Enables continuous receive mode. If a receive callback has been setup, it will be trigger
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on any incoming data until either an `OP_MODE` or `DIO0` mode are change.
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### `void lora32_enable_single_rx(lora32_cfg_t *lora)`
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* **NOTE** This requires `DIO1` for complete functionality.
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* **NOTE** Implenentation incomplete.
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Enables single receive mode. Will either trigger `RXDONE` on `DIO0` or `RXTIMEOUT` on `DIO1`
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### `void lora32_enable_cad(lora32_cfg_t *lora)`
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Enables Channel Activity Detection. Will trigger callback `cad_done` with `bool detected` on completion.
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If activity was detected, it will also trigger `cad_detected`
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## Callbacks
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`lora32_cfg_t` provides several callbacks based on `DIO0` interrupts. Most functionality is provided through
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these, favoring async operations over syncronous polling.
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### `lora32_cfg_t->receive(uint8_t size)`
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Triggered from `RXCONTINUOUS` and `RXSINGLE` modes. Provides the number of bytes available. Should be followed
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up with a call to `lora32_read_data` to retrieve data from FIFO buffer.
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### `lora32_cfg_t->tx_done()`
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Triggers after call to `lora32_send` completes, as long as `DIO0` mode has not been changed.
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### `lora32_cfg_t->cad_done(bool detected)`
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Triggers after call to `lora32_enable_cad` completes (ie times out) or channel activity is detected.
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`bool detected` will reflect these two states.
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### `lora32_cfg_t->cad_detected()`
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Triggers after call to `lora32_enable_cad` successfully detects channel activity.
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