2019-12-29 19:58:05 +00:00
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//! ## A Rusty interface for the RN2903 serial protocol
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//!
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//! The RN2903 is a LoRa and FSK transciever for the 915MHz ISM band, commonly used in USB
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//! devices like the LoStik.
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//!
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//! This crate provides a safe, idiomatic interface using cross-platform native serial
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//! functionality via `serialport`. This supports, for instance, a LoStik connected to a USB
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//! TTY or virtual COM port, or a RN2903 connected via a TTL serial interface.
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//!
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//! See the [`Rn2903` struct](struct.Rn2903.html) for the bulk of the crate's functionality.
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2019-12-28 16:29:09 +00:00
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// One of the critical aspects of this library is error handling. Because it is intended
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// to communicate with an external device, any operation could discover a disconnection
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// from the RN2903 serial link, so everything which does such communication will return
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// a `Result<T, rn2903::Error>`.
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2019-12-28 17:04:52 +00:00
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#[macro_use]
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extern crate quick_error;
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2019-12-28 16:29:09 +00:00
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use std::io;
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quick_error! {
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2019-12-29 19:58:05 +00:00
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/// The primary error type used for fallible operations on the RN2903.
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2019-12-28 16:29:09 +00:00
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#[derive(Debug)]
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pub enum Error {
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/// The connection to the RN2903 was impossible for some reason. Perhaps an
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/// invalid port was specified, or this program does not have permission to
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/// access the specified port.
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ConnectionFailed(err: serialport::Error) {
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cause(err)
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description(err.description())
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from()
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}
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/// The device to which the serial link is connected does not appear to be
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/// a RN2903, because it did not respond to `sys get ver` correctly.
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WrongDevice(version: String) {
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description("failed to verify connected module")
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display("Could not verify version string. Expected a RN2903 firmware revision, got '{}'",
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version)
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}
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2019-12-31 22:48:51 +00:00
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/// The device returned a response that doesn't make sense, given the command that
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/// was issued.
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BadResponse(expected: String, response: String) {
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description("bad response from module")
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display("Received a bad response from the module. Expected '{}', got '{}'.",
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expected, response)
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}
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/// The device is operating in a mode which prevents MAC functionality from being
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/// paused, but a pause was requested.
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CannotPause {
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description("the LoRaWAN MAC cannot be paused")
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display("The LoRaWAN MAC cannot be paused right now, but a pause was requested.")
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}
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2019-12-28 16:29:09 +00:00
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/// The program has become disconnected from the RN2903 module due to an I/O
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/// error. It is possible the device was physically disconnected, or that the
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/// host operating system closed the serial port for some reason.
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Disconnected(err: io::Error) {
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cause(err)
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description(err.description())
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from()
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}
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}
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}
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2019-12-31 22:48:51 +00:00
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impl Error {
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fn bad_response<S: Into<String>, T: Into<String>>(expected: S, response: T) -> Self {
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Self::BadResponse(expected.into(), response.into())
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}
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}
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2019-12-28 16:29:09 +00:00
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/// Universal `Result` wrapper for the RN2903 interface.
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2019-12-29 19:58:05 +00:00
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pub type Result<T> = std::result::Result<T, Error>;
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2019-12-28 16:29:09 +00:00
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// It's first necessary to actually connect to the module. To this end, the library
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// exports all the configuration information needed to configure a serial port to
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// communicate correctly with an RN2903.
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use core::convert::AsRef;
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2019-12-28 17:04:52 +00:00
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use core::time::Duration;
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use serialport::prelude::*;
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2019-12-28 16:29:09 +00:00
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use std::ffi::OsStr;
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2019-12-28 17:04:52 +00:00
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use std::io::prelude::*;
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2019-12-28 16:29:09 +00:00
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use std::thread;
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2019-12-29 19:58:05 +00:00
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/// Returns the `SerialPortSettings` corresponding to the default settings of
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/// an RNB2903.
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2019-12-28 16:29:09 +00:00
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///
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/// Information obtained from Microchip document 40001811 revision B. Timeout is by
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/// default set to a very long time; this is sometimes modified on the `SerialPort` itself
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/// during certain operations.
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2019-12-29 19:58:05 +00:00
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///
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/// # Examples
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///
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/// Opening a serial port with slightly modified settings. In this case, the baud rate
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2019-12-31 22:50:46 +00:00
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/// has been reduced.
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2019-12-29 19:58:05 +00:00
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///
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/// ```no_run
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/// let settings = serialport::SerialPortSettings {
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/// baud_rate: 9600,
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/// ..rn2903::serial_config()
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/// };
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///
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/// serialport::open_with_settings("/dev/ttyUSB0", &settings)
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/// .expect("Could not open serial port. Error");
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/// ```
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2019-12-28 16:29:09 +00:00
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pub fn serial_config() -> SerialPortSettings {
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SerialPortSettings {
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baud_rate: 57600,
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data_bits: DataBits::Eight,
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flow_control: FlowControl::None,
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parity: Parity::None,
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stop_bits: StopBits::One,
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2019-12-29 19:58:05 +00:00
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timeout: Duration::new(65535, 0),
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2019-12-28 16:29:09 +00:00
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}
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}
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// Once connected to a serial port, the library needs to verify that it is actually
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// connected to a RN2903 and not some other serial device. To this end, the `Rn2903`
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// wrapper struct's `::new()` function checks the output of the `sys get ver` command,
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// which is well-specified.
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2019-12-29 19:58:05 +00:00
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/// Turn the raw bytes into a String for display.
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pub fn bytes_to_string(bytes: &[u8]) -> String {
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2019-12-28 18:48:12 +00:00
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(&*String::from_utf8_lossy(bytes)).into()
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2019-12-28 17:04:52 +00:00
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}
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2019-12-28 16:29:09 +00:00
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/// A handle to a serial link connected to a RN2903 module.
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///
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2019-12-29 19:58:05 +00:00
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/// This library guarantees safety regardless of the state of the RN2903. Refer to the
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/// documentation for sections and individual associated functions for specifics.
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///
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/// # Examples
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///
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/// Basic functionality can be obtained just by using `::new_at()` and `::transact()`.
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/// For instance, blinking the LoStik's LED:
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///
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/// ```no_run
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/// # use rn2903::Rn2903;
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/// # use std::time::Duration;
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/// # use std::thread;
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/// let mut txvr = Rn2903::new_at("/dev/ttyUSB0")
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/// .expect("Could not open device. Error");
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/// loop {
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/// txvr.transact(b"radio set pindig GPIO10 0").unwrap();
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/// thread::sleep(Duration::from_millis(1000));
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/// txvr.transact(b"radio set pindig GPIO10 1").unwrap();
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/// thread::sleep(Duration::from_millis(1000));
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/// }
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/// ```
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2019-12-28 16:29:09 +00:00
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pub struct Rn2903 {
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2019-12-28 17:04:52 +00:00
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port: Box<dyn SerialPort>,
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2019-12-28 16:29:09 +00:00
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}
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2019-12-31 22:50:46 +00:00
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/// # Meta (type) Functions
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2019-12-29 19:58:05 +00:00
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///
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/// These functions deal with the type `Rn2903`, providing ways to create and manipulate
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2019-12-31 22:48:51 +00:00
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/// the structure itself.
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2019-12-29 19:58:05 +00:00
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/// ## Creating an `Rn2903`
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/// There are several ways to create a `Rn2903` wrapper for an RN2903 serial connection.
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/// `::new_at()` is the recommended method, but `::new()` can be useful if the platform
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/// does not support named serial ports, or some extra configuration is needed.
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2019-12-28 16:29:09 +00:00
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impl Rn2903 {
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2019-12-29 19:58:05 +00:00
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/// Opens a new connection to a module at the given path or port name, with the
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/// default (and usually correct) settings from
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/// [`serial_config`](fn.serial_config.html).
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///
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/// # Example
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2019-12-31 22:50:46 +00:00
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///
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2019-12-29 19:58:05 +00:00
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/// Connecting to a module accessible over the USB0 TTY.
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/// ```no_run
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/// # use rn2903::Rn2903;
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/// let txvr = Rn2903::new_at("/dev/ttyUSB0")
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/// .expect("Could not open device. Error");
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/// ```
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2019-12-28 16:29:09 +00:00
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pub fn new_at<S: AsRef<OsStr>>(port_name: S) -> Result<Self> {
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let sp = serialport::open_with_settings(&port_name, &serial_config())?;
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Self::new(sp)
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}
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2019-12-29 19:58:05 +00:00
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/// Open a new connection to a module over the connection described by the given
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/// `SerialPort` trait object.
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2019-12-28 17:04:52 +00:00
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pub fn new(port: Box<dyn SerialPort>) -> Result<Self> {
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2019-12-29 19:58:05 +00:00
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let mut new = Self::new_unchecked(port);
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2019-12-28 17:04:52 +00:00
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let version = new.system_version()?;
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if &version[0..6] != "RN2903" {
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Err(Error::WrongDevice(version))
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2019-12-28 16:29:09 +00:00
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} else {
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2019-12-28 17:04:52 +00:00
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Ok(new)
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2019-12-28 16:29:09 +00:00
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}
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}
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2019-12-29 19:58:05 +00:00
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/// Open a new connection to a module over the connection described by the given
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/// `SerialPort` trait object without performing a `sys get ver` check.
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2019-12-28 16:29:09 +00:00
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///
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2019-12-29 19:58:05 +00:00
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/// The results of operations on a `Rn2903` struct that does _not_ represent an
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/// actual connection to an RN2903 module are completely unpredictable, and may
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/// result in lots of badness (though not memory unsafety).
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pub fn new_unchecked(port: Box<dyn SerialPort>) -> Self {
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Self { port }
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}
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2019-12-31 22:50:46 +00:00
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2019-12-29 19:58:05 +00:00
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/// Acquires temporary direct access to the captured `SerialPort` trait object.
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///
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/// Use this access to, for example, reconfigure the connection on the fly,
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/// or set flags that will be used by devices this crate is unaware of.
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///
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/// # Example
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///
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/// Raising and then lowering the RTS signal, for example to signal a bus observer
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/// to switch on.
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/// ```no_run
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/// # use rn2903::Rn2903;
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/// # use std::thread;
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/// # use std::time::Duration;
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/// # let mut txvr = Rn2903::new_at("/dev/ttyUSB0")
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/// # .expect("Could not open device. Error");
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/// txvr.port().write_request_to_send(true)
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/// .expect("Could not set RTS. Error");
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/// thread::sleep(Duration::from_millis(25));
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/// txvr.port().write_request_to_send(false)
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/// .expect("Could not set RTS. Error");
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/// ```
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pub fn port(&mut self) -> &mut dyn SerialPort {
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&mut *self.port
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2019-12-28 18:48:12 +00:00
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}
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2019-12-29 19:58:05 +00:00
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}
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2019-12-28 18:48:12 +00:00
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2019-12-31 22:50:46 +00:00
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/// # Low-level Communications
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2019-12-29 19:58:05 +00:00
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impl Rn2903 {
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/// Writes the specified command to the module and returns a single line in response.
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2019-12-28 18:48:12 +00:00
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///
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/// This function adds the CRLF to the given command and returns the response without
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/// the CRLF.
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2019-12-29 19:58:05 +00:00
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///
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/// This is the preferred low-level communication method, since the RN2903 is supposed
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/// to respond with a single line to every command.
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pub fn transact(&mut self, command: &[u8]) -> Result<Vec<u8>> {
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self.send_line(command)?;
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self.read_line()
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}
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2019-12-31 22:48:51 +00:00
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/// Convenience function for situations where only one response is expected according
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/// to the module's documentation. Receiving another response means something wacky
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/// is going on.
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fn transact_expecting(&mut self, command: &[u8], expectation: &[u8]) -> Result<()> {
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let bytes = self.transact(command)?;
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if bytes != expectation {
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2019-12-31 22:50:46 +00:00
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Err(Error::bad_response(
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bytes_to_string(expectation),
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bytes_to_string(&bytes),
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))
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2019-12-31 22:48:51 +00:00
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} else {
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Ok(())
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}
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}
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2019-12-29 19:58:05 +00:00
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/// Writes the specified command to the module, adding a CRLF and flushing the buffer.
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///
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/// Using [`::transact()`](#method.transact) is preferred.
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pub fn send_line(&mut self, line: &[u8]) -> Result<()> {
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let bytes: Vec<u8> = line.iter().chain(b"\x0D\x0A".iter()).cloned().collect();
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let mut cursor = 0;
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while cursor < bytes.len() {
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cursor += self.port.write(&bytes[cursor..])?;
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2019-12-31 22:50:46 +00:00
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}
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2019-12-28 16:29:09 +00:00
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self.port.flush()?;
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2019-12-29 19:58:05 +00:00
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thread::sleep(Duration::from_millis(500));
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Ok(())
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2019-12-28 16:29:09 +00:00
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}
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2019-12-29 19:58:05 +00:00
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/// Reads bytes from the device until a CRLF is encountered, then returns the bytes
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2019-12-28 18:48:12 +00:00
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/// read, not including the CRLF.
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2019-12-29 19:58:05 +00:00
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///
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/// Using [`::transact()`](#method.transact) is preferred.
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2019-12-28 17:04:52 +00:00
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// This operation waits 12ms between each 32-byte read because the LoStick has
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// the hiccups.
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2019-12-29 19:58:05 +00:00
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pub fn read_line(&mut self) -> Result<Vec<u8>> {
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2019-12-28 17:04:52 +00:00
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let mut vec = Vec::with_capacity(32);
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loop {
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let mut buf = [0; 32];
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self.port.read(&mut buf)?;
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vec.extend_from_slice(&buf);
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// Check if crlf was added to the buffer.
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let mut found_lf = false;
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let mut found_crlf = false;
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for byte in vec.iter().rev() {
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if found_lf {
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if *byte == b'\x0D' {
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found_crlf = true;
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break;
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}
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} else {
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found_lf = *byte == b'\x0A';
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}
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}
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if found_crlf {
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break;
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} else {
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thread::sleep(Duration::from_millis(12));
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}
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}
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2019-12-28 18:48:12 +00:00
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// Remove zeroes and crlf
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while (b"\x00\x0D\x0A").contains(&vec[vec.len() - 1]) {
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vec.pop();
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}
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2019-12-28 17:04:52 +00:00
|
|
|
Ok(vec)
|
|
|
|
}
|
2019-12-29 19:58:05 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/// # System API Functions
|
|
|
|
impl Rn2903 {
|
|
|
|
/// Queries the module for its firmware version information.
|
|
|
|
///
|
|
|
|
/// Returns a `String` like `RN2903 1.0.3 Aug 8 2017 15:11:09`
|
|
|
|
pub fn system_version(&mut self) -> Result<String> {
|
|
|
|
let bytes = self.transact(b"sys get ver")?;
|
|
|
|
Ok(bytes_to_string(&bytes))
|
2019-12-31 22:50:46 +00:00
|
|
|
}
|
2019-12-29 20:56:44 +00:00
|
|
|
|
|
|
|
/// Queries the module for its firmware version information.
|
|
|
|
///
|
|
|
|
/// As `::system_version()`, but returns bytes.
|
|
|
|
pub fn system_version_bytes(&mut self) -> Result<Vec<u8>> {
|
|
|
|
self.transact(b"sys get ver")
|
|
|
|
}
|
2019-12-29 20:59:16 +00:00
|
|
|
|
2019-12-31 22:45:45 +00:00
|
|
|
/// Resets the CPU on the connected module. State in memory is lost and the MAC
|
|
|
|
/// starts up upon reboot, automatically loading default LoRaWAN settings.
|
2019-12-31 22:50:46 +00:00
|
|
|
///
|
2019-12-31 22:45:45 +00:00
|
|
|
/// Returns the system version, like `::system_version_bytes()`.
|
|
|
|
pub fn system_module_reset(&mut self) -> Result<Vec<u8>> {
|
|
|
|
self.transact(b"sys reset")
|
|
|
|
}
|
|
|
|
|
2019-12-29 20:59:16 +00:00
|
|
|
/// Performs a factory reset on the connected module. All EEPROM values are
|
|
|
|
/// restored to factory defaults. All LoRaWAN settings set by the user are lost.
|
2019-12-31 22:45:45 +00:00
|
|
|
///
|
2019-12-29 20:59:16 +00:00
|
|
|
/// Returns the system version, like `::system_version_bytes()`.
|
2019-12-31 22:45:45 +00:00
|
|
|
pub fn system_factory_reset(&mut self) -> Result<Vec<u8>> {
|
|
|
|
self.transact(b"sys factoryRESET")
|
2019-12-29 20:59:16 +00:00
|
|
|
}
|
2019-12-28 17:04:52 +00:00
|
|
|
}
|
2019-12-31 22:48:51 +00:00
|
|
|
|
|
|
|
/// # MAC API Functions
|
|
|
|
impl Rn2903 {
|
|
|
|
/// Pauses the LoRaWAN MAC functionality on the device, returning the number of
|
|
|
|
/// milliseconds for which the MAC can remain paused without affecting LoRaWAN
|
|
|
|
/// functionality.
|
|
|
|
///
|
|
|
|
/// This command can fail with `CannotPause`, meaning the device is operating in a
|
|
|
|
/// mode (like LoRaWAN Class C mode) in which pausing the MAC for any period of time
|
|
|
|
/// would result in degraded service.
|
|
|
|
pub fn mac_pause(&mut self) -> Result<u32> {
|
|
|
|
let val = bytes_to_string(&self.transact(b"mac pause")?);
|
|
|
|
let ms: u32 = match val.parse() {
|
|
|
|
Ok(v) => v,
|
2019-12-31 22:50:46 +00:00
|
|
|
Err(_) => return Err(Error::bad_response("<integer>", val)),
|
2019-12-31 22:48:51 +00:00
|
|
|
};
|
|
|
|
if ms == 0 {
|
|
|
|
Err(Error::CannotPause)
|
|
|
|
} else {
|
|
|
|
Ok(ms)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/// Resumes LoRaWAN MAC functionality on the device after being paused.
|
|
|
|
pub fn mac_resume(&mut self) -> Result<()> {
|
|
|
|
self.transact_expecting(b"mac resume", b"ok")
|
|
|
|
}
|
|
|
|
}
|