Application Report
SPRABR8 – January 2013
DALI Communication on the AC LED Lighting and
Communications Developer’s Kit
Brett Larimore ..................................................................................................................................
ABSTRACT
The AC LED Lighting and Communications Developer’s Kit provides a great way to learn and experiment
with using a single MCU to accurately control a series of LED strings and efficiently control the power
stages needed to make the LEDs work. This application report explains how to use the
TMDSIACLEDCOMKIT to communicate via the DALI protocol. The accompanying Code Composer
Studio™ project enables the MCU to control the kit’s power stages, LED strings, and serves as a DALI
slave. The MCU used to perform all these tasks is a Piccolo™ F28027 microcontroller.
Figure 1. TMDSIACLEDCOMKIT
Code Composer Studio, Piccolo, C2000 are trademarks of Texas Instruments.
All other trademarks are the property of their respective owners.
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DALI Communication on the AC LED Lighting and Communications
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1
DALI Summary
www.ti.com
WARNING
This EVM is meant to be operated in a lab environment only and is
not considered by TI to be a finished end-product fit for general
consumer use.
This EVM must be used only by qualified engineers and
technicians familiar with risks associated with handling high
voltage electrical and mechanical components, systems and
subsystems.
This equipment operates at voltages and currents that can result in
electrical shock, fire hazard or personal injury if not properly
handled or applied. Equipment must be used with necessary
caution and appropriate safeguards employed to avoid personal
injury or property damage.
It is your responsibility to confirm that the voltages and isolation
requirements are identified and understood, prior to energizing the
board and or simulation. When energized, the EVM or components
connected to the EVM should not be touched.
1
2
3
Contents
DALI Summary .............................................................................................................. 2
Implementation .............................................................................................................. 3
References ................................................................................................................... 8
List of Figures
1
TMDSIACLEDCOMKIT..................................................................................................... 1
2
Manchester Encoding ...................................................................................................... 3
3
DALI Hardware Interface ................................................................................................... 3
4
Major Files in the DALI Project ............................................................................................ 5
5
Example of DALI Host GUI ................................................................................................ 6
6
AC LED Lighting and Communications Board Jumpers and Connectors Diagram ................................ 7
List of Tables
1
1
DALI Commands Supported ............................................................................................... 4
DALI Summary
Digital addressable lighting interface (DALI) is a common lighting standard that is used primarily to control
lighting in building and home networks. It is often used as a more feature rich alternative to 0 V - 10 V
dimmers. DALI has the ability to control up to 64 single units, control 16 groups and create 16 scenes.
DALI has a full set of more the 250 commands that can be used to do things from changing dimming
values, editing ballast addresses, and querying the status of various ballasts.
DALI is defined first in IEC 60929 Annex E and updated in IEC 62386. The major reason for the update
was to include support for LED modules and color control. The DALI software given in the application
report mentioned in Section 2 shows how to use DALI as specified in IEC 60929 Annex E and performs a
subset of the full instruction set.
2
DALI Communication on the AC LED Lighting and Communications
Developer’s Kit
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The DALI protocol is a half-duplex digital communications interface composed of forward and backward
frames. The forward frames consists of one start bit, one address byte, one data byte, and two stop bits.
The backward frame (the response) consists of one start bit, one data byte, and two stop bits.
DALI uses Manchester encoding, which means that within a bit frame, and low-to-high transition is defined
as a “1”, whereas, a high-to-low transition is defined as a “0” (see Figure 2).
0
1
Figure 2. Manchester Encoding
2
Implementation
A hardware interface and a Code Composer Studio project were developed to control the LLC resonant
stage, control the LED stages, and receive DALI commands on a F28027 device. The driver software for
DALI communications is found within the DALI folder of the Code Composer Studio project.
The DALI driver and project are meant to be used as an aid in developing a DALI system.
This project can be found at www.ti.com/controlsuite:
development_kits\IsoACLighting_vX.X\IsoACLighting-F28027-DALI
2.1
Hardware interface
Optoisolators and a schmitt-trigger inverter convert the DALI signal into unipolar signals, which can be
converted to DALI commands by the Piccolo C2000™ microcontroller (see Figure 3).
DAL I
3V3
R8
10K
3V3
3V3
C7
DAL I-TX
DAL I+
U5
74AC14
12V0
1
2
3
4
5
6
7
TP3
TB7
Trm-2
R6
DNP
U4
ASSR
3
1
2
2
1
4
DAL I-
R9
R7
DNP
1A
1Y
2A
2Y
3A
3Y
GND
100n
Vcc
6A
6Y
5A
5Y
4A
4Y
14
13
12
11
10
9
8
R11
10K
2
DAL I-RX
R10
2
TP4
1
4
2
3
10K
2
3V3
U6
SFH615
200R
2
2
DAL I+
DAL I-
Figure 3. DALI Hardware Interface
The DALI-RX net terminal in Figure 3 connects to GPIO-19 on the F28027 device. GPIO-19 is then
configured to be an eCAP peripheral input in the initialization phase of the device startup. The C2000
microcontroller’s eCAP capture unit is able to count cycles between transitions, which allows the C2000
device to translate the Manchester encoding to DALI commands (with the help of software).
DALI-TX is attached to GPIO-18, which is used directly as a GPIO. The state of the GPIO is governed by
software and the timing is governed by a counter within the eCAP peripheral. Note that the above TX and
RX are relative to the fixture controlled by the Piccolo F28027.
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Implementation
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Although the DALI standard recommends allowing incorrect connection of + and -, it has not been done in
this version of hardware. To resolve this, one would need to add a diode bridge at the input to U6, such
that U6 will only ever see a unipolar input.
Although not tried by TI, R6 and R7 could be populated with 10K resistors if the TMDSIACLEDCOMKIT is
to be used as a DALI master. This provides the pull-up and pull-downs needed such that the two signals
are made differential.
2.2
DALI Software Driver
The DALI.c file primarily defines the DALI driver, whereas, the DALI_command.c and
DALI_special_command.c define what each specific command should do.
The software driver assumes that the C2000 device (and light device) is the slave in a DALI network. The
software driver uses the C2000 device’s eCAP peripheral to decode the DALI communication input as well
as to give the timing for the DALI transmissions that are needed to answer the master’s query commands.
The reason that the eCAP can be used in this way is because the eCAP has two modes of operation.
In capture mode, the eCAP triggers on a particular edge and records the timestamp of a given transition.
In this way, the eCAP can be used to measure the time between two edges. Knowing that the DALI bit
period is about 416 µs long, a Manchester encoded bitstream can be interpreted in 1s and 0s to find the
correct DALI command. This DALI bitstream is then translated into changing the actual_level, which is the
light output for the DALI slave.
The other mode of the eCAP peripheral is APWM mode. In this mode, a certain period is defined and the
eCAP peripheral fires an interrupt when the period value is reached. The eCAP peripheral’s timer then
restarts at 0. This allows the DALI transmit function to have a known timebase from which to transmit a
DALI packet.
The C2000 device’s GPIO18 is used as a GPIO to transmit DALI and GPIO19 is configured as an eCAP
to receive DALI commands.
Table 1. DALI Commands Supported
Commands Fully
Supported
Commands That are
Partially Supported (1)
Commands Not
Supported
0-8
42-47
16-33
64-128
144-155
194-197
237-241
48-63
160-165
224-227
242-251
130-143
252-255
158-159
Commands Not Tested
Reserved Commands
129
9
10-15
156-157
228
34-41
Standard Commands
176-193
166-175
198-223
229-236
Special Commands
256-258
259
260-261
264-266
267
269
268
271
270
273-275
262-263
272
(1)
2.3
Commands listed as partially supported do work, but do not store data to non-volatile memory as required.
DALI Project
Before working with this project, you should have already run and experimented with the IsoACLightingF28027 project found at www.ti.com/controlsuite:
development_kits\TMDSIACLEDCOMKIT_v1.0\IsoACLighting-F28027
4
DALI Communication on the AC LED Lighting and Communications
Developer’s Kit
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That project and its documentation thoroughly explain the TMDSIACLEDCOMKIT and how the F28027
controls the kit’s power stages. The IsoACLighting-F28027-DALI project builds on the knowledge found
there.
Hardware-wise, the only change that may need to be done to make the DALI project work is that the
jumpers at [Main]-J4 and [Main]-J5 both need to be moved and placed to connect positions 2 and 3.
The key software difference between the IsoACLighting-F28027 project and the IsoACLighting-F28027DALI project is that the IsoACLighting-Comms.c file has changed and now interfaces and calls functions in
the DALI.c file. The Comms.c file also initializes and turns on the resonant stage so that the DALI interface
can directly change the brightness of the LED strings without needing to do anything with the LLC
resonant stage. This DALI.c file contains the DALI driver. Figure 4 gives some details on the major files
used in the DALI project.
IsoACLighting-Main.c file
IsoACLighting-Comms.c
DALI.c
DALI_command.c
Initializes the power stages
Serves as a bridging file
between the Main.c file and
the DALI.c file
DALI-init() - Initializes DALI
interrupts
Provides support for
commands 1-255
Configures the power stage
interrupts
Initializes the DMX512
system by calling the
Comms_Init function in
IsoACLighting-Comms.c
Runs several periodically
called tasks such as
Comms_Run()
Initializes system variables
such as the DALI address
that the light should look at
Calls DALI_init() in DALI.c
Starts up the LLC
Resonant power stage
after some time has gone
passed
Calls the
DALI_updateBallast()
function in DALI.c
periodically.
DALI_updatesBallast() responsible for updating
the brightness of the light.
Provides fading
functionality as well. Calls
the DALI_translate function
periodically.
DALI_translate() - This
function is responsible for
taking the information
taken from the DALI
interrupts and turning these
into commands. Calls
DALI_command or
DALI_special_command
depending on the type of
command received.
DALI_special_command.c
Provides support for
commands 256-275
Figure 4. Major Files in the DALI Project
To run the project and have DALI communications work, you need a DALI master such as the Tridonic
DALI-BM RS-232 (with winDIM 4.0) or another DALI master.
1. Run the software and configure the hardware as instructed in build 1 and 2 of the
TMDSIACLEDCOMKIT-CCS guide.
2. Attach the USB cable to [M8]-JP1.
3. Ensure that [Main]-J3 is populated.
4. Put jumpers across positions 2 and 3 of [Main]-J4 and [Main]-J5.
5. Attach a DALI master to TB7. Attach the “+” terminal of the master to the “+” terminal of TB7.
6. Setup the DALI master and software as instructed in the master’s user manuals and guides.
7. Connect a 12 V DC supply to [M7]-JP1.
8. Switch [M7]-SW1 to the “Ext” position.
9. Open Code Composer Studio.
10. Import the IsoACLighting-F28027-DALI project found at www.ti.com/controlsuite:
development_kits\TMDSIACLEDCOMKIT_vX.X\ IsoACLighting-F28027-DALI
11. Compile the software.
12. Connect and Flash the code by clicking the “bug” button.
13. Reset the processor and then click restart (so that the program starts at the beginning of main) in
Code Composer Studio.
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14. Enable real-time mode and enable continuous refresh of the watch window in Code Composer Studio.
15. Click the green play button to run the software. (Step 16 should be done shortly after this step is
complete.)
16. Carefully plug the AC cable into the wall. Once this step is complete, the board will be dangerous to
touch.
Note that the LLC resonant power supply is automatically set to turn on about 10 seconds after the
board is powered.
17. Use the DALI master’s software to communicate brightness information to the kit. By default the
ballast has no group or scenes assigned to it. The controlCARD’s LED LD3 should toggle when any
DALI command is received by the F28027 MCU.
18. Look at the below variables (and many more) from a Code Composer Studio watch window . Each of
these is defined as a character, but should be viewed as an integer in the watch window:
(a) actual_level – the brightness value reference given by the DALI
(b) Gui_IsetLed[0-5] – the brightness level for each LED string (provided by the actual_level variable).
This variable is Q14.
(c) short_address – the address of the DALI light; 0xFF (broadcast only) by default
(d) min_level – the minimum value that the light can output; set as 90
(e) max_level – the maximum value that the light can output; set as 254
(f) group_0_7 and group_8_f – 8-bit variables in which each bit corresponds to whether the light is in a
particular group or not
(g) scene – an array that corresponds to the light’s defined value in a particular scene
19. Use the DALI master to turn off the LEDs on the TMDSIACLEDCOMKIT once done.
20. Unplug the power cable from the wall.
21. Wait at least 60 seconds before touching the board.
NOTE: This demo can also be run without the external DC/DC power supply connected and without
Code Composer Studio. However, it is safer to use the external power supply first. Once the
DALI code is Flashed into the device, which is done in the procedure above, you can rerun
the above with the following exceptions: remove the DC/DC supply, switch [M7]- SW1 away
from “Ext”, and skip steps 10 - and 16.
Figure 5. Example of DALI Host GUI
6
DALI Communication on the AC LED Lighting and Communications
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[Main] BS5
Banana Jack
for secondary
side GND
[Main] J16
+12V DC
header for fan
[Main] BS4
Banana Jack for
Resonant output
[M7] SW1 –
Low Voltage
Power Switch
[M7] JP1 –
12-15V external
power connector
[Main] BS6 –
Banana Jack for
LED Bus input
[Main] J2 –
400V-to-12V
enable jumper
[Main] J20 –
400V-to-18V
enable jumper
[Main] TB1-TB6 – LED
string connectors for
LED panel
[Main] BS2 –
Banana Jack for
primary side GND
[Main] BS3 –
Banana Jack for
Resonant Input
[Main] TB7 – DALI
communications
header
[Main] BS1 –
Banana Jack for
PFC output
[Main] J4-J7 –
Communications
selection
jumpers
[Main] J1 –
100-pin DIMM
controlCARD
connector
[Main] P1 –
Universal AC
Connector
(85-250Vac)
[Main] J3 – JTAG
TRSTn Jumper
[M8] JP1 –
USB Connection
for onboard
emulation
www.ti.com
Implementation
Figure 6. AC LED Lighting and Communications Board Jumpers and Connectors Diagram
DALI Communication on the AC LED Lighting and Communications
Developer’s Kit
7
References
3
References
•
•
•
8
www.ti.com
www.ti.com/controlsuite:
– TMDSIACLEDCOMKIT_CCS — provides detailed information on the IsoACLighting project within
Code Composer Studio. The document goes through the project in an easy to use labstyle format.
development_kits\TMDSIACLEDCOMKIT_vX.X\~Docs\ TMDSIACLEDCOMKIT_CCS.pdf
– TMDSIACLEDCOMKIT-HWdevPkg — a folder containing various files related to the hardware on
the AC LED Lighting and Communications Developer’s Kit board (schematics, bill of materials,
Gerber files, PCB layout, and so forth).
development_kits\TMDSIACLEDCOMKIT_vX.X \ ~TMDSIACLEDCOMKIT-HwdevPkg[R4]\
– TMDSIACLEDCOMKIT-HWGuide — presents full documentation on the hardware found on the AC
LED Lighting and Communications Developer’s board.
development_kits\TMDSIACLEDCOMKIT_vX.X\~Docs\ TMDSIACLEDCOMKIT -HWGuide.pdf
Digital Addressable Lighting Interface (DALI) Implementation Using MSP430 Value Line
Microcontrollers (SLAA422)
DALI Activity Group Manual — Provides an overview of the DALI standard.http://www.daliag.org/c/manual_gb.pdf
DALI Communication on the AC LED Lighting and Communications
Developer’s Kit
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