Introduction

This technical brief gives a solution for a Manchester code transceiver. It is implemented in Digital Addressable Lighting Interface (DALI-2) systems, in which it serves as an encoder and decoder for data transmission on the physical layer. The transceiver is implemented using PIC16F1779, a Microcontroller Unit (MCU) with several Core Independent Peripherals (CIPs). These peripherals can be used to perform an important part of the tasks in hardware, thus reducing the Central Processing Unit (CPU) load and obtaining a faster response.

The solution presented here is applicable to any other 8-bit PIC® microcontroller that offers the same minimal set of CIPs. DALI-2 is an IEC standard (known as IEC62386).

This document describes the modulation implementation in hardware and the data transmission by software encapsulation. For a proper understanding of the process, the technical brief also covers the following:

• Manchester Coding Convention
• DALI-2 Forward and Backward Frames
• Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART), Configurable Logic Cell (CLC) and Timer (TMR) Functionality
• EUSART, TMR and CLC Merged Solution for Manchester Encoder
• EUSART and TMR with Hardware Limit Timer (HLT) Merged Solution for Manchester Decoder