MC144144

Features:

• Conforms to FCC Report and Order as Amended by the Petition for Reconsideration on Gen. Doc. 911
• Conforms to EIA608 for XDS Data Structure
• Supports Four Different Data Channels for Field 1 and Five Different Data Channels for Field 2, Time
   Multiplexed  within the Line 21 Data Stream: Captions Utilizing Languages 1 and 2, Text Utilizing Languages 1
   and 2 and XDS Support
• Output Logic Provides Hardware Underline Control and Italics Slant Generation
• Single Supply, Operating Voltage Range: 4.75 to 5.25 V
• Supply Current: 20 mA (Preliminary)
• Operating Temperature Range: 0 to 70
• Composite Video Input Range: 0.7 to 1.4 V _pp
• Horizontal Input Polarity: Either Positive or Negative
• Internal Timing and Sync Signals Derived from OnChip VCO


Pinout




Specifications

Symbol	Characteristic	Value	Unit
VDD(A)	Analog DC Supply Voltage	0.5 to 6.0	V
VDD(D)	Digital DC Supply Voltage	0.5 to 6.0	V
Vin	DC Input Voltage Analog Section Digital Section	0.5 to VDD(A) + 0.5 0.5 to VDD(D) + 0.5	V
Vout	DC Output Voltage, Digital Section	0.5 to VDD(D) + 0.5	V
Iin	DC Input Current, per Pin	+ 10	mA
Iout	DC Output Current per pin	+ 20	mA
IDD	DC Supply Currentper	+30	mA
PD	Power Dissipation per Package	300	mW
Tstg	Storage Temperature	65 to + 150
TL	Lead Temperature, 1 mm from Case for 10 Seconds	260

* Maximum ratings are those values beyond which damage to the device may occur. Functional operation should
   be  restricted to the limits in the Electrical Characteristics tables or Pin Description section.

This device contains protection circuitry to guard against damage due to high static voltages or electric fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated voltages to
this highimpedance circuit.


Description

The MC144144 is a Line 21 closedcaption decoder for use in television receivers or settop decoders conforming to the NTSC standard. Capability for processing and displaying all of the latest standard Line 21 closedcaption format transmissions is included. The MC144144 requires a closedcaption encoded composite video signal, a horizontal sync signal, and an external keyer to produce captioned video. RGB and box signal outputs are provided, which along with the mode select, allow simple interfacing to either color or blackandwhite TV receivers.

Display storage is accomplished with an onchip RAM. A modified ASCII character set, MC144144 includes several non English characters, is decoded by an onchip ROM. An onscreen character appears as a white or colored dot matrix on a black background.

Captions MC144144 (videorelated information) can be up to four rows appearing anywhere on the screen and can be displayed in two modes: rollup, painton, or popon. With rollup captions, the row scrolls up and new information appears at the bottom row each time a carriage return is received. Popon captions work with two memories. One memory is displayed while the other is used to accumulate new data. A special command causes the information about MC144144 to be exchanged in the two memories, thus causing the entire caption to appear at once.

When text (nonvideo related information) is displayed, the rows contain a maximum of 32 characters over a black box which overwrites the screen. Fifteen rows of characters are displayed in the text mode.

An onchip processor controls the manipulation of data for storage and display. Also controlled are the loading, addressing, and clearing of the display RAM. The processor transfers the data received to the RAM during scan lines 21 through 42. The operation of the display RAM MC144144, character ROM, and output logic circuits are controlled during scan lines 43 through 237. The functions of the MC144144 are controlled via a serial port which may be configured to be either I²C or SPI.