MC44725AVFU Freescale Semiconductor, MC44725AVFU Datasheet - Page 20

• Manufacturer Part Number: MC44725AVFU
• Manufacturer: Freescale Semiconductor

Specifications of MC44725AVFU

• Lead Free Status / Rohs Status: Not Compliant

Copy Generation Management 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,
letter box and or normal -16:9 or 4:3.
Data is Double-Buffered and is latched at the start of Field 1.
(see figures 24 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. This DVE will automatically NULL characters when there is no CC data to encoder after the CC data
has been processed by setting the $87[5] register.
the Frame sync falling edge of previous Frame, updating Frame 2 data during Frame1 display and Frame1 data
during Frame2 display.
When the $87[4] register is set, the DVE will generate the parity bit automatically.
(see figures 26 and 27 for sub-address register descriptions.)
Wide Screen Signaling (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, letter
box and or normal -16:9 or 4:3.
Data is Double-Buffered and is latched at the start of Field 1.
(see figures 25 for sub-address register descriptions.)
It is recommended to write CC data only to the inactive frame. Field1 and Field2 data are double-buffered by
This document contains information on a new product. Specifications and information herein are subject to change without notice.
For More Information On This Product,
Go to: www.freescale.com
No.
20
MC44724A/5A Rev 0.05 07/15/98