TIDUFB0 July   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Input Devices (DALI 103)
    2. 1.2 Control Gear (DALI 102)
    3. 1.3 Control Devices (Application Controllers)
    4. 1.4 Introduction
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Manchester Encoding
      2. 2.2.2 Using Opto-Emulators Instead of Optocouplers
    3. 2.3 Highlighted Products
      1. 2.3.1 MSPM0G350x
      2. 2.3.2 ISOM8111
        1. 2.3.2.1 ISOM8111 Features
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
      1. 3.2.1 DALI Stack Layer
    3. 3.3 Test Setup
      1. 3.3.1 Configuring the PIR
    4. 3.4 Test Results
      1. 3.4.1 Event Message When PIR Detects a Motion
      2. 3.4.2 Event Message Generation Through Report Timer
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Layout Prints
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Authors

1.4 Introduction

The DALI protocol is a half-duplex digital communication composed of forward and backward frames. Forward frames consist of one start bit, one address byte, one data byte, and two stop bits. The backward frame (the response after reception of a query or memory command in the forward frame) consists of one start bit, one data byte, and two stop bits. DALI uses Manchester encoding, and the voltage of the interface power supply can vary from 11.5V to 22.5V per the standard.

DALI enables the easy installation of robust, scalable, and flexible lighting networks. DALI originated to enable digital control, configuration, and querying of fluorescent ballasts, replacing the simple, one-way, broadcast-like operation of 0/1–10V analog control.

With DALI, the broadcast option is also available; in addition, with simple configuration, each DALI device can be assigned a separate address, allowing digital control of individual devices.

Furthermore, the DALI devices can also be programmed to operate in groups. This provides excellent flexibility since the lighting systems can be reconfigured by software reprogramming, without the need to change the wiring. Different lighting functions and moods can be achieved in different rooms or areas of a building, and then easily adjusted and optimized.

Wiring is relatively simple; DALI power and data is carried by the same pair of wires, without the need for a separate bus cable. The polarity of the wires does not have to be observed, in contrast with 0/1–10V systems where wiring errors are common.

The system is comprised of Control Devices (application controller), Control Gears, and Input Devices:

  • Device Control Instructions
  • Device Configuration Instructions
  • Device Queries
  • Instance Control Instructions
  • Special Commands

Table 1-1 shows details of single-controller or multi-controller variants.

Table 1-1 Single- and Multi-controllers
SINGLE-CONTROLLERSMULTI-CONTROLLERS
Only one allowed on the DALI busMore than one can be used on the same bus
Receiver is optionalSupports event-driven operation of input devices
Can allow polling of input devices, or checking status of control gearUses a short address