February 2018
10
M
icrocontrollers
& P
rocessors
DALI 2.0 software stack
for microcontrollers saves costs
By Marcelo Williams Silva and Georg Huba, Infineon Technologies
This article introduces a DALI 2.0
software stack for XMC1000
microcontrollers. This stack was
developed by Infineon in close
cooperation with Xenerqi and
accelerates design of
LED lighting applications.
Amongst other things, the XMC1000
microcontroller family with ARM-Cor-
tex-M0 offers optimised peripherals and
functionalities for smart lighting control. This
makes it possible to address a host of different
applications both indoors and in commercial
buildings. It is within this environment that
DALI (Digital Addressable Lighting Interface)
has established itself as a standardised inter-
face for controlling lighting control gear. With
DALI 2.0, interoperability between compo-
nents from different manufacturers has been
further improved, whilst the integration of
sensors significantly extends the possibilities
for smart lighting applications. Infineon has
partnered with Xenerqi to develop a DALI 2.0
software stack for its XMC1000 microcontrol-
lers. This significantly reduces development
time and costs.
Smart lighting solutions extend conventional
LED lighting with new functionalities such as
wired and wireless connectivity, programma-
bility, sensors, improved lighting quality and
intelligent colour mixing. With special periph-
erals and functionalities, XMC microcontrol-
lers are predestined for numerous modern
LED lighting systems. For instance, automatic
dimming and colour control for multi-chan-
nel LEDs is supported. In addition to the LED
control, the MCUs of the 1200, 1300 and 1400
series can also handle DALI or DMX commu-
nication. Furthermore, the XMC microcon-
trollers can be used to implement the power
supply for the LED driver, supporting all stan-
dard two-stage switched-mode power supply
topologies.
The key features of the XMC1000 family for
smart lighting systems are: automatic bright-
ness control (based on high-frequency pulse
modulation), flicker-free dimming via 9 out-
put channels, automatic exponential dim-
ming and linear intensity changes for natural,
eye-friendly brightness and colour changes,
high-speed integrated analog comparators for
current control, and closely coupled peripheral
functions for various digital power conversions.
The introduction of the LED into all areas
of lighting technology has led to extensive
changes in the control of lights.What was once
controlled in the past with phase dimmers or
an analog 1…10V interface is now digitally
connected. The most popular standardised
interface DALI – originally designed for dim-
ming fluorescent lamps – has established itself
as the standard for lighting design, driven
by the success of LED lights. With DALI 2.0,
interoperability has been further enhanced,
whilst the integration of sensors opens up
new possibilities for smart lighting applica-
tions. The XMC1000 family with the ARM
Cortex M0 core is available in the XMC1100,
XMC1200, XMC1300 and XMC1400 series
with flash versions up to 200 KB and enclo-
sures with up to 64 pins. Even the entry-level
XMC1100 series, with its basic feature set,
provides many industrial applications with
cost-effective access to the 32-bit world with
12-bit AD converters and powerful 16-bit tim-
ers of Capture/Compare Unit 4 (CCU4). The
XMC1200 series includes additional appli-
cation-specific features such as a peripheral
unit for capacitive touch applications and for
the control of LED displays (LEDTS), high-
speed analog comparators and an innovative
Brightness and Colour Control Unit (BCCU).
The BCCU permits flicker-free dimming and
colour control of LEDs with virtually no
processor load. What is more, versions are
available for the extended temperature range
from -40 °C up to 105 °C.
Last but not least, the XMC1300 series is
specifically designed for motor control and
digital power conversion applications. In
addition to a particularly powerful Capture/
Compare Unit 8 (CCU8) with two compare
channels and asymmetric PWM functionality
and a position interface (POSIF) for precise
detection of the motor position, it also offers
a mathematical coprocessor. The latter per-
mits efficient sensorless FOC (field-oriented
control) solutions for electric motors. The
XMC1300 series also offers variants for the
