This document summarizes the student's internship placement at Merlyn Electronics working on their Halo LED display system. The student improved the system's encoder to be compatible with the DMX512 lighting protocol. During debugging, the student fixed issues like flickering from timing problems, incorrect color formats, and colors changing with odd green values. The student gained work experience assessing and improving an unknown system as well as improving their English and experiencing living in England.

1. By Thibaut Pascual

2.  Introduction
 Merlyn Electronics
 The Halo system
 Placement assessment
 Conclusion

3. - Validate our degree in a two years
university diploma
- Put in practice the theoretical
knowledge acquired
- Improve my English and discover a
new country

4.  Introduction
 Merlyn Electronics
› Global presentation
› Merlyn’s work
 The Halo system
 Living in England
 Conclusion

5. Global presentation
- Created by Jonathan Eagle in 1987
- Small company specialized in interactive advertising system
- Works with the world leader in advertising street furniture JC Decaux

6. - Building innovate advertising campaign and integrating
them into bus shelters

7.  Introduction
 Merlyn Electronics
 The Halo system
› How does it work?
› My project
› The DMX512 protocol
› Halo software
 Placement assessment
 Conclusion

8. - Use to reinforce corporate images on billboard with a lightning
frame
- 1024 pixels individually controlled by 63 brightness levels and 16,7
million colours.

9. How does it works ?
3 1 1. Dual 7
2. Multimodem
3. Encoder board
4. Decoder board
5. LED board
4 2
5

10. How does the encoder work?
2 1
1. Serial Port
3 2. SD card reader
3. The manager
4 4. The controllers and
the flash memories
5. RS422 I/O
5

11. How does the encoder work?
The manager :
- Fetch the data from the
I2C serial port or from the SD card
- Fill the external/internal
SPI controller’s memories
The controllers :
- Send the data to the
decoder board in the correct order

12. How does the decoder work?
1 3
2
1. RS422 Input
2. µController 8051 Send the data to the different LED board
3. Serial output

13. How does the LED board work?
2
1
1. RGB LEDs
2. DM163
- Shift register
- create a PWM signal to drive the LED

14. My project
- Make the encoder compatible with the DMX512 protocol
- Fetch the data
from the serial
port
- Fetch the data
from the SD card
DMX512

15. The DMX 512 protocol
- Mainly use for stages lightning devices
- Control up to 512 devices with a data byte each
Mark Time After Break : 8µs – 1s
Mark Time Between Frame : 0 – 1s

16. The Halo software
- Assembly
- To read the code I use the Silicon Laboratories IDE

17. The Halo software
- Part of the DMX software already created
- DMX decoder
- Functions to send DMX512
- What I had to do :
- Fetch the data from the SD card and from the serial port
and send them to the decoder

18. The Halo software
Main functions :
- Start DMX
- Create the break and the MTAB
- PutDMXFrame
- Put the data byte to send in a Frame

19. The Halo software
1st software

20. The Halo software
- First bug : The flickering error
- Timing problem
Cause : No Mark Time Between Frame
Solution : Add Mark Time Between frame in the PutDMXFrame

21. The Halo software
The serial port commands
Example : [SCrrggbb]
The manager will fill the controller’s internal memory
Offset Values
100h RRh
101h GGh
102h BBh
103h RRh
104h GGh
105h BBh - Second bug : Wrong colour format
106h RRh
107h GGh
108h BBh
- GGRRBB instead of RRGGBB
109h RRh
10Ah GGh
… …
15Fh BBh

22. The Halo software

23. The Halo software
- Third bug : The colours changing with odd value for the
green byte
[SC00FE00] (FEh = 254)  Right colour
[SC00FF00] (FFh = 255)  Wrong colour
- Cause : The board changing when the decoder send the data to 4
different LED board.

24.  Introduction
 Merlyn Electronics
 The Halo system
 Placement assessment
› Work assessment
› Living in England
 Conclusion

25. Work assessment
- The serial commands are totally operational
- One LED still not working when fetching the data from the SD card
- Understand an unknown system and a big software
- Learned how to debug a software

26. Living in England
- Lived in Salford
- Improve my English by
earing different accents

27. - Good social and working experience
- I know now I really want to continue my studies
- Thanks to Jonathan Eagle for receiving me
- Thanks to David for the evening at the PUB
after a day work.