1. DMX512 Programmable Theater Lighting Controller Jeff Sand and Kris Kopel Advisor: Dr. Don Schertz May 8, 2001

2. Outline Objectives Digital Lighting Control Overview System Block Diagram (Hardware) Firmware Software Results

3. Objectives Generate DMX512 output to control lighting devices Enable PC control to change dimmer levels Develop USB platform for future use Write commercial quality firmware, driver, and windows software In short, Design a complete marketable system using a top down approach

4. Digital Theatrical Lighting Console Lights Dimmers Intelligent Luminaries DMX512

5. DMX512 Protocol United States Institute for Theatre Technology (USITT) standard Controls up to 512 dimmers/devices Serial and asynchronous bitstream 250 kbits/s RS-485 physical implementation 32 nodes on one chain

6. System Block Diagram Motorola 68376  Controller Personal Computer Input Blocks RS485 Driver MAX483 DMX512 Output USB Transceiver Philips PDIUSBD12

7. Microcontroller Interfaces Data bus, chip selects, and external IRQ used for USB transceiver Queued Serial Module (QSM) –Serial Communication Interface (SCI) for DMX output –Queued Serial Peripheral Interface (QSPI) for input blocks Internal RAM for data storage EPROMs for program code Background Debug Mode (BDM) for development without a monitor program

8. Input Block Serial A/D MAX148 Serial Shift Register 74166 Fader Inputs Momentary Push Buttons Out to  Controller QSM Module QSPI Control Lines Latch 74373

9. Firmware Written in assembly language Interrupt driven DMX512 output Fader/Button data acquisition USB Communication over data bus Main program loop for standalone mode only

10. DMX Output Stream

11. DMX Output Status? Last Channel? End Break DMX Output Status <- Data DMX Output Status <- Start DMX Output Status <- Break DMX Output Status <- Mark Output Start Code Output Data Byte Exit ISR Start Break Set Timer noyes break data markstart SCI Interrupt Routine

12. QSPI Interrupt Routine Read/Clear Status Register Read all Buttons Read 8 Faders Buttons Faders Reprogram QSPI for Faders Reprogram QSPI for Buttons Increment Chip Selects Re-Enable QSPI Exit ISR Faders or Buttons? Last Fader Block? yes no

13. Read interrupt register Bus Reset Suspend Change Data Endpoint In Data Endpoint Out Exit ISR Control Endpoint In Control Endpoint Out Handle Reset Handle Change Data left to send? no Send it yes Read Data into Buffer Data left to send? Send it yes Set Address String Descriptor Get Descriptor Device Descriptor Configuration Descriptor USB Interrupt Routine

14. Windows Driver Windows kernel mode USB driver Recognizes and initializes device Registers device with Windows to be accessed by user applications Handles reads from/writes to device Plug n Play and Windows power management compatible

15. Windows Device Detection

16. Windows Software Three modes of operation –Direct fader control –Software dimmer “patching” –Programmed lighting queues Uses Windows common controls Uses Windows timers

17. Windows Software

18. Results Completed DMX512 Output (Hardware and Firmware) –Adjustable number of channels –Proper output frequency Completed Input Blocks (Hardware and Firmware) –Buttons, Faders, and control circuitry wire wrapped onto panel –One master block and two 8 channel scenes –Firmware capacity for 128 faders and buttons

19. DMX Output Result

20. Results Wrote a firmware routine for direct external fader control with master control, two scenes, and crossfade Implemented USB firmware (all functions necessary for this device) Interfaced USB peripheral chip with microcontroller on data bus Master power switch

21. Results Wrote functional Windows kernel mode driver Wrote windows user application –Currently does not properly interface with driver Tested complete unit with DMX light and it worked perfectly We plan to test the device in the Bradley theater in the near future