AN1465 datasheet(2/14 Pages) MICROCHIP

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AN1465

DS01465A-page 2

 2012 Microchip Technology Inc.

Electrical Specifications

The physical low level or active state for DALI has been

defined with the interface voltage of < 9.5V. The high-

level condition, or DALI idle, is an interface voltage

between 9.5V to 22.5V, most common being 16V.

Maximum system current is limited to 250 mA.

Response time of the current limiter circuit is < 10 µs.

Each component connected to the interface may

consume a maximum of 2 mA. Connectors are non-

polarized at the receiver. DALI is usually optically

isolated from the microcontroller and has a data

transfer rate of 1200 bits per second.

FIGURE 2:

DALI ELECTRICAL

SPECIFICATIONS

Connectors

There are no specific connectors dedicated for the

DALI interface. Two-wire connectors with common

screw terminals or push fit suffice (Figure 3).

FIGURE 3:

TWO-WIRE CONNECTORS

Cabling

Due to the transmission rate, there is no need for spe-

cial cables or wires. Two-wire standard electrical

cables can get the job done. 18 AWG, class 1 or 2

cables (solid or stranded) are commonly used on many

fixtures. They are often purple in color and usually

rated 600V. A maximum voltage drop of up to 2V is

allowed across the connecting wires from the interface

supply to each system component. The maximum

distance between two communicating units should be

300 meters (984 feet).

DALI CIRCUITS

There is no specification or recommendations on how

to implement the circuit design for DALI. The following

optically isolated circuit interfaces a PIC16F1947 to the

DALI bus.

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