Creltek Video DAC

The Creltek Video DAC allows the conversion of 24-bit parallel RGB pixel data (sometimes called a "TTL" or "Parallel" interface) to a variety of analog video output formats, including VGA as well as S-Video and Composite video signals, which are commonly used in standard-definition television.

The board includes a high quality 24-bit RGB video DAC supporting a maximum pixel clock of 180 MHz. This DAC produces a very clean output that is far superior to what you can get from simple R2R resistor networks or other DACs that are not designed for video. Also included is a high-quality TV Encoder, which provides simultaneous S-Video and Composite video outputs and produces a beautiful picture on TV. A set of 3 jumpers allows you to route the DAC's video output to either the VGA port or to the onboard TV Encoder. (Please note that both VGA and TV Output cannot be used simultaneously; it wouldn't make sense anyway since there are no standard-definition TV modes that correspond with standard VGA timings.)

The onboard TV Encoder can be set to either PAL or NTSC encoding standards, with the installation of the appropriate crystal and jumper setting. PAL requires a 4.433618 MHz crystal with the "PAL" jumper closed, and NTSC requires 3.579545 MHz crystal with the "PAL" jumper open. The crystal is socketed, allowing it to be easily changed. The inclusion of either or both standard crystals is available as an option when ordering.

The onboard Video DAC operates on 3.3V power, while the onboard TV Encoder operates on 5V power. The board itself requires a single 5VDC power supply (an onboard linear regulator supplies 3.3V power to the Video DAC). NOTE: All digital inputs and control signals are specified for 3.3V CMOS levels, and should only be interfaced with 3.3V logic.

NOTE: This board is a "Video DAC + TV Encoder" ONLY. It does not include a frame buffer, and does not generate your pixel clock, pixel data stream, or sync pulses. It's up to you to supply the board with appropriate signals including parallel pixel data, pixel clock, and horizontal and vertical sync pulses. This can be accomplished with a sufficiently powerful microcontroller, FPGA, or other system providing parallel digital video output.

Features

• Single 5V power supply
• 3.3V digital I/O
• Onboard high-quality 24-bit RGB DAC (max. 180 MHz pixel clock)
• Onboard high-quality TV Encoder (supports both PAL and NTSC encoding)
• VGA connector
• S-Video connector
• Composite Video RCA connector
• NTSC or PAL TV output standard selectable by jumper (requires installation of appropriate crystal)
• Socketed FSC crystal allows for easy change
• Video output may be routed to VGA connector -OR- on-board TV Encoder via jumper block (not both simultaneously)
• When using the on-board TV Encoder, both S-Video and Composite outputs are driven and may be used simultaneously
• Proper termination and coupling of all output signals

CDK3404 Video DAC Datasheet

AD724 TV Encoder Datasheet

Board Pinout

• Pins 00-07: Red Data (pin 0 is LSB)
• Pins 08-15: Green Data (pin 8 is LSB)
• Pins 16-23: Blue Data (pin 16 is LSB)
• Pin 24: Pixel Clock
• Pin 25: /BLANK (DAC output Blank, active low, internally pulled up) - usually not used; may be left unconnected
• Pin 26: /CSYNC (DAC composite Sync-on-Green, active low, internally pulled down) - usually not used; may be left unconnected
• Pin 27: /HSYNC (Horizontal Sync, active low, internally pulled up) - connected to VGA port and TV Encoder
• Pin 28: /VSYNC (Vertical Sync, active low, internally pulled up) - connected to VGA port and TV Encoder
• Pin 29: ENC (TV Encoder Enable, active high, internally pulled up) - may be pulled low to disable TV Encoder and save power
• Pin 30: +5VDC (positive power supply)
• Pin 31: GND (negative power supply and digital ground)

Additionally, several small ground pads are provided along the edge of the board if additional ground connections are needed for shielding or noise reduction purposes. These are located to the left of pins 0, 8, 16, 24, and 25.

Be sure to check out our other awesome Creltek products on Tindie!