NTSC Video Using the 68HC908QY4
 

Jed Margolin



This project  was done for the Motorola Flash Innovation 2003 Contest run by Circuit Cellar Magazine (www.circuitcellar.com) and won one of the First Place Prizes.
 

The Motorola 68HC908QY4 is used to produce an NTSC video signal which can be used in several applications. By using 28.63636 MHz for the clock, the QY4 bus speed is 7.15909 MHz. which is twice the chroma frequency of 3.579545 MHz. The Interrupt Timer is used to generate an interrupt every 455 bus cycles resulting in an interrupt rate of 15.734 KHz. which is precisely the frequency of NTSC sync. Because interrupts that occur in the middle of a multi-cycle instruction are not recognized until the instruction is completed, the main line consists of a table of NOPs; all of the sync functions are performed during the interrupt, and the interrupt routine is returned to the start of the NOP table.
 

One application using the QY4 to produce NTSC sync is an NTSC Test Pattern Generator which produces simple test patterns in order to evaluate a TV's geometric distortion, high voltage regulation, and interlace quality.




Another application is a VCR Pacifier to allow a VCR to record an audio-only signal such as from a radio. The VCR Pacifier also includes a real-time clock which is displayed either in video or by using the TV's closed captioned decoder. Low-bandwidth data from the 68HC908QY4's A/D inputs can be displayed the same way, turning the VCR into a two-channel data logger.




Since we will need to program the 68HC908QY4, a Programmer/Emulator is included at no extra charge.




And as a bonus, a Video Line Trigger is presented which counts video lines from an external NTSC video source and produces a pulse to trigger an oscilloscope at the selected line(s). (This was built on a protoype board that already contained another project. The circuitry used in the Video Line Trigger is outlined in red. If you build it you can leave out the other stuff.)



The project is available in two forms:
 
 

HTML (Good for viewing online, contains active links)
Microsoft Word (Zipped with schematics, code, and references)

Jed Margolin
San Jose, CA
September 30, 2003

Here is a list of all the contest winners.
 

Grand Prize Winner
 
 Name  Country  Project Name  Prize 
 Richard Dreher  USA   Remote Observation Station  Grand Prize

 

DOMESTIC US, NORTH and SOUTH AMERICA
 
 Name  Country  Project Name  Prize
 Jed Margolin   USA  NTSC Video Using the 68HC908QY4  First
 Bruce Pride  USA  Smart-E-Touch  First
 Cheng-Yang Tan  USA  Wireless, Solar-Powered, Acoustic Wave Soil &
 Moisture Detection System		  First
 Sitti Amarittapark  USA  Servo Digitizer  Dist. Excel
 Matthew Bieker  USA  Laser Spirograph  Dist. Excel
 Thomas Dvorak  USA  PCB Drill Platform  Dist. Excel
 Charles Edmondson  USA  Intelligent Humidity Compensated Thermostat  Dist. Excel
 Themi Kotsiras  Canada  Martial Arts Digital Simulator  Dist. Excel
 Kenneth Lumia  USA  Enviro-Alarm  Dist. Excel
 James McGuire &
 Thomas Burke		  USA  Peak Power Controller  Dist. Excel
 Colin O'Flynn  Canada  Flow Rate Failure Detector  Dist. Excel
 Bruce Pride  USA  Nitro-Debugger  Dist. Excel
 Robert Schmidinger  USA  Boost Pump Control  Dist. Excel

 

FOREIGN - EUROPEAN and AFRICA
 
 Name  Country  Project Name  Prize
 Victor Kremin  Ukraine  Low-cost Intelligent Sensors Network  First
 Robert Lacoste  France  Smart Tracker 2: An Innovative Wire Tracker  First
 Radek Vaclavik  Czech Republic  Gas Alarm  First
 Jens Altenburg  Germany  Magic Lamp  Dist. Excel
 Andreas Bartelmus  Germany  Rear Muffler Actuator Control  Dist. Excel
 Damien Bataille &
 Menassa Degaule		  France  4I4O Option Board  Dist. Excel
 Victor Kremin  Ukraine  Artificial Vision System for the Blind  Dist. Excel
 Grzegorz Mazur  Poland  Low Cost Evaluation Board/Programmer  Dist. Excel
 Salvador Perdomo  Spain  Radio Security System  Dist. Excel
 Alberto Ricci Bitti  Italy  DVD-Thermometer  Dist. Excel
 Alberto Ricci Bitti  Italy  Wireless Mousetrap Monitoring System  Dist. Excel
 Tito Smailagich  Yugoslavia  Counter  Dist. Excel
 Radek Vaclavik  Czech Republic  Tiny Altimeter  Dist. Excel

 

FOREIGN - ASIA and PACIFIC RIM
 
 Name  Country  Project Name  Prize 
 Mihai Tudosie  Japan  Programmable DC Power Supply  First
 Raymond Weisling  Indonesia  Acoustical Cellular Automata Parallel Processor  First
 Hua Zhou  China  Tilt Detector  First
 Virachat Boondharigaputra  Thailand  µTelemetry: The Micro Telemetry System
 for R/C Race Cars		  Dist. Excel
 Zhang Chongguang
 Zhou Haibo		  China  Intelligent Fishbowl  Dist. Excel
 Kamal Gendi  Australia   Mini Node  Dist. Excel
 Sunil Jha  India  i-Button based Personal Identification System  Dist. Excel
 Steven Wong Kai Juan  Singapore  Low-power Optical Smoke Detector  Dist. Excel
 Ganesh Raaja Maharajan  India  Blood Pressure Monitor  Dist. Excel
 Indranil Majumdar  India  Automobile Cruise Control  Dist. Excel
 Lindsay Meek  Australia  VGA Signal Probe  Dist. Excel
 H.N. Naveen  India  Intellistick: The Eye of the Blind  Dist. Excel
 Hua Zhou  China  RS232-RS485 Communication Multiplexer  Dist. Excel

 

Distinctive Merit
 
 Name  Country  Project Name
 Dave Barnard  USA  TV/VCR Remote Control Exterior Light Controller
 Radu Constantinescu  USA  The Internet Plug
 Timothy Crawford  USA  Spa Controller
 Ganesh Raaja Maharajan  India  Temperature Logger
 Jorge Andres Baena Osorio  Colombia  MiniRec Personal Voice Recording System
 Seenath  Punnakkal  & 
 Sameer Cholayil 		  USA  Touchscreen Controller
 Seenath  Punnakkal  & 
 Sameer Cholayil 		  USA  Micro Mini DAQ
 Seenath  Punnakkal  & 
 Sameer Cholayil		  USA  Tlogger
 Robert Schmidinger  USA  RV Refrigeration Control
 Hock Wei Soon   Singapore  Proximity Sensor for the Visually Handicapped

 

All of the projects can be downloaded from the Circuit Cellar Web site at: http://www.circuitcellar.com/fi2003 .