mc44724 Freescale Semiconductor, Inc, mc44724 Datasheet - Page 16

• Manufacturer Part Number: mc44724
• Description: Digital Video Encoder
• Manufacturer: Freescale Semiconductor, Inc

Copy Generation Managment System (CGMS) Encoding
CGMS signals can be encoded by the DVE onto output video line 20 (525 / 60 for Japan).
CGMS identification signals also identify and control the TV screen presentation mode - wide screen,
letterbox and or normal -16:9 or 4:3.
(see figures 18 for sub-address register descriptions.)
Closed-Caption Encoding
Closed-Captioned or Extended Data Service signals can be encoded by the DVE onto output video line 21/284
(NTSC) and line 22/335 (PAL). The CC data is input through the serial bus interface. Two 8-bit byte data pairs
are encoded for each field. There are four registers for holding the data - two bytes per field. The serial data is
7bit US-ASCII MSB first, proceeded by an odd parity bit. Total 8-bits. (P-7-6-5-4-3-2-1-0)
The DVE automatically generates the required clock run in and start bit for CC encoding. (see figure 16.)
When Closed-Captioning is enabled, the system micro processor (uP) should update the CC data once each
frame. The system uP should also write NULL characters when there is no CC data to encode. It is also
recommended to write CC data only to the inactive frame. Field1 and Field2 data are double-buffered by the
Frame sync falling edge of previous Frame, updating Frame 2 data during Frame1 display and Frame1 data
during Frame2 display.
(see figures 20 for sub-address register descriptions.)
Wide Screen Signalling (WSS) Encoding
WSS signals can be encoded by the DVE onto output video line 23 (625 / 50 for Europe).
WSS identification signals also identify and control the TV screen presentation mode - wide screen,
letterbox and or normal -16:9 or 4:3.
(see figures19 for sub-address register descriptions.)
This document contains information on a new product. Specifications and information herein are subject to change without notice.
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MC44724/5 Rev 0.21 03/25/97