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UM1632

Structure of final user application

The final user application uses the DALI slave library and consists of the following three

layers:

•

Main user application

•

DALI stack layer

•

I/O pin driver layer

2.1

User application

The structure of the user application is entirely comprised of IAR project files. The

application code is in one source file, "main.c", in which the whole user ballast control is

implemented. This code calls the DALI slave library functions.

The user application example included in the DALI slave library package is designed to work

with "STM8L1526-EVAL" and "STEVAL_ILM001V1 (DALI transceiver board)". The

STM8L1526-EVAL is a small printed circuit board (PCB) with an integrated STM8L152C6

device which demonstrates the STM8L capabilities. The DALI transceiver board is

connected to the STM8L1526-EVAL as a physical layer extension. It provides voltage level

conversion and optical isolation between the DALI bus and the STM8L1526-EVAL

(according to the DALI specification requirements).

The main task of the user application is to initialize the DALI stack and implement the light

intensity control function (callback function); this function is ballast dependent. The user

application also periodically controls some event flags: if the DALI slave library sets an

event flag and it indicates a pending event, the user application must call the appropriate

service routines (from the DALI slave library) to execute the necessary commands.

The user application example uses timer 3 to control the light intensity of the LED diode

present on the STM8L1526-EVAL. Timer 3 generates the pulse-width modulation (PWM) for

the LED diode (using the callback function). The main program loop checks event flags,

executes actions for active flags, and provides power management (Low power state if the

DALI bus is quiet) and error management (reports hardware errors). For all these activities,

the user application calls functions from the DALI slave library.

Figure 3. Structure of DALI stack layer

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