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dmx-rdm-rs

Rust library for communicating DMX512 (ANSI E1.11) and DMX-RDM (ANSI E1.20) over a RS485 bus by using interchangeable drivers. This library features no-std as well as no-alloc support (no heap allocation) to target embedded as well as os platforms.

Please refer to the official specifications published by the ESTA.

This library is wip, it has not yet received extensive testing and the api might not be final.

Currently available drivers

Platform Driver OS Embedded
FTDI Uarts with RS485 Transceiver dmx-rdm-ftdi ✅ ❌
Enttec DMX Pro dmx-rdm-enttec-pro ✅ ❌
RP2040 (Raspberry Pi Pico) dmx-rdm-rp2040 ❌ ✅

Usage

These examples show the basic usage using the dmx-rdm-ftdi driver. These examples work together.

Controller

use dmx_rdm::dmx_controller::{DmxController, DmxControllerConfig};
use dmx_rdm::unique_identifier::{PackageAddress, UniqueIdentifier};
use dmx_rdm::utils::run_full_discovery;
use dmx_rdm_ftdi::{FtdiDriver, FtdiDriverConfig};

fn main() {
  let dmx_driver = FtdiDriver::new(FtdiDriverConfig::default()).unwrap();
  let mut dmx_controller = DmxController::new(dmx_driver, &DmxControllerConfig::default());

  let mut devices_found = vec![];

  // Unmute all dmx responders.
  dmx_controller
          .rdm_disc_un_mute(PackageAddress::Broadcast)
          .unwrap();

  let mut uid_array = [UniqueIdentifier::new(1, 1).unwrap(); 512];
  loop {
    // Search for devices.
    let amount_devices_found = run_full_discovery(&mut dmx_controller, &mut uid_array).unwrap();

    // Add found devices to vector.
    devices_found.extend_from_slice(&uid_array[..amount_devices_found]);

    // Have all devices been found and muted?
    if amount_devices_found != uid_array.len() {
      break;
    }
  }

  for device in devices_found {
    match dmx_controller.rdm_set_identify(PackageAddress::Device(device), true) {
      Ok(_) => println!("Activated identify for device_uid {device}"),
      Err(error) => {
        println!("Activating identify for device_uid {device} failed with {error}")
      },
    }
  }
}

Responder

use dmx_rdm::command_class::RequestCommandClass;
use dmx_rdm::dmx_receiver::{DmxResponderHandler, RdmResponder};
use dmx_rdm::rdm_data::RdmRequestData;
use dmx_rdm::rdm_responder::{DmxReceiverContext, RdmResponderConfig, RdmResult};
use dmx_rdm::types::{DataPack, NackReason};
use dmx_rdm::unique_identifier::UniqueIdentifier;
use dmx_rdm_ftdi::{FtdiDriver, FtdiDriverConfig};

struct RdmHandler {
  identify: bool,
}

const PID_IDENTIFY_DEVICE: u16 = 0x1000;

impl RdmHandler {
  fn handle_get_identify(&self) -> RdmResult {
    RdmResult::Acknowledged(DataPack::from_slice(&[self.identify as u8]).unwrap())
  }

  fn handle_set_identify(&mut self, parameter_data: &[u8]) -> Result<RdmResult, std::fmt::Error> {
    // Check if the parameter data has the correct size
    if parameter_data.len() != 1 {
      return Ok(RdmResult::NotAcknowledged(
        NackReason::DataOutOfRange as u16,
      ));
    }

    // Convert identify flag to bool and set that in the state.
    self.identify = parameter_data[0] != 0;

    println!("Current identify is {}", self.identify);

    // Acknowledge request with an empty response.
    Ok(RdmResult::Acknowledged(DataPack::new()))
  }
}

impl DmxResponderHandler for RdmHandler {
  type Error = std::fmt::Error;

  fn handle_rdm(
    &mut self,
    request: &RdmRequestData,
    _: &mut DmxReceiverContext,
  ) -> Result<RdmResult, Self::Error> {
    match request.parameter_id {
      PID_IDENTIFY_DEVICE => match request.command_class {
        RequestCommandClass::GetCommand => Ok(self.handle_get_identify()),
        RequestCommandClass::SetCommand => {
          self.handle_set_identify(&request.parameter_data)
        },
        _ => Ok(RdmResult::NotAcknowledged(
          NackReason::UnsupportedCommandClass as u16,
        )),
      },
      _ => Ok(RdmResult::NotAcknowledged(NackReason::UnknownPid as u16)),
    }
  }
}

fn main() {
  let dmx_driver = FtdiDriver::new(FtdiDriverConfig::default()).unwrap();

  // Create rdm_responder with space for 32 queued messages.
  let mut dmx_responder = RdmResponder::<_, 32>::new(
    dmx_driver,
    RdmResponderConfig {
      uid: UniqueIdentifier::new(0x7FF0, 1).unwrap(),
      // Won't add PID_IDENTIFY_DEVICE since this is a required pid.
      supported_pids: &[],
      rdm_receiver_metadata: Default::default(),
    },
  );

  let mut rdm_handler = RdmHandler { identify: false };

  loop {
    // poll for new packages using our handler
    match dmx_responder.poll(&mut rdm_handler) {
      Ok(_) => (),
      Err(error) => println!("'{error}' during polling"),
    }
  }
}

Drawbacks/Issues

If you have any ideas on how to improve on the current state, please contribute.

  • The controller currently blocks until the response to a request is received
    • maybe this should be separable in the future
  • Discovery has to be implemented by people themselves for now
    • I am currently considering a polling system on the Controller
  • No sub device / proxy device support yet
  • SUPPORTED_PARAMETERS are hard to evaluate.
  • Lacking unit test coverage
  • polling, lots of blocking functionality
  • AckTimer is hard to handle
    • If an Enttec DMX Pro is used as a slave this has to be supported
    • ola solved this by using callbacks, this is not an option because we can't use threading
    • maybe will attempt a similiar approach, but instead of threading we will use polling
      • this could make the library considerable harder to use
  • Lots of memory copying because of the heavy use of heapless::Vec
  • weird heapless datatypes (in order to support no-alloc)
  • end-to-end testing is hard to and has not been done for the most part
    • as of now there is no proper standard verification
  • there are two types of devices, those that need the computer to repeat the dmx packages as often as required (rp2040, ftdi) and those that have this functionality built in (enttec dmx pro)
    • this is not handled at all, instead the send_dmx functions do something different depending on the driver

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in dmx-rdm-rs by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.