MAX7432A Ver la hoja de datos (PDF) - Maxim Integrated

Número de pieza

componentes Descripción

Lista de partido

MAX7432A

Standard Definition Video Reconstruction Filters and Buffers

Maxim Integrated 

Standard Definition Video Reconstruction

Filters and Buffers

tWAIT

tT

t1

t0

t1

tO A B

CD

t0 A B

CD

tP

0 OR 1

tP

00 OORR 11

tP

tT

t1

t1

t1

Figure 8. Read Timing Diagram

READS 1ST BIT (LSB)

READS 2ND BIT

REPEAT TO READ

6 MORE BITS

A: μP WILL RELEASE BUS BY TIME A

B: μP CAN START READING BIT AT TIME B

C: μP HAS UNTIL TIME C TO FINISH READING BIT

D: DEVICE WILL RELEASE BUS BY TIME D

NOTE: TIME A, B, C, D ARE REFERENCED TO t0.

tWAIT

DATA: 1***000

tT

t0

t0

t0

t0

t0

t0

t1

tT

t1

t1

t1

LSB

MSB

Figure 9. Broadcast Timing Diagram

When processing composite video set the clamp level to

+1V (CLEVEL = 0). Use the MAX7430 to process two

synchronous composite signals simultaneously. Use the

MAX7432A to process three synchronous composite

signals simultaneously.

Y/C Video Filtering

The MAX7430 is ideally suited for processing S-Video (Y/C)

signals (Figure 10). Ensure that IN1_ filters the signal that

contains the sync information (Y) since the clamping on

IN2_ is internally controlled by the master channel (IN1_)

sync. Set the clamp level for IN1_ to +1V (CLEVEL1 = 0)

and set the clamp level for IN2_ to +1.5V (CLEVEL2 = 1).

Use two MAX7428s for Y/C video filtering. Since only the

Y signal contains the sync, a typical Y/C video-filtering

application requires a master-slave configuration of the

SYNCIO. The MAX7428 processing the Y signal should

have SYNCIO configured as an output, which in turn dri-

ves the SYNCIO of the second MAX7428, processing the

C signal that has its SYNCIO configured as an input

(Figure 11). Clamping level for the Y signal should be set

for +1V (CLEVEL = 0), and clamping level for the C sig-

nal should be set for +1.5V (CLEVEL = 1). Use the

MAX7432A to filter one Y/C and one composite video

signal that are synchronous.

Component Video (RGB

or Y Pb Pr) Filtering

Component video consists of three separate signals.

Typically the three signals are separate red, green, and

blue (RGB) signals or Y (luma) and two color difference

signals: B-Y (Pb) which is blue minus luma and R-Y (Pr),

which is red minus luma. Sync information is included

with the Y signal of Y Pb Pr component video, or in the

case of RGB, sync is usually carried on the G or on a

separate H sync line. The MAX7432A is ideally suited

for filtering component video signals. Ensure that the

sync signal (Y for Y Pb Pr signals and usually G for RGB

signals) is filtered by IN1_ since IN2_ and IN3_ are

internally synced to IN1_. Set the clamp level for IN1_

to +1V (CLEVEL1 = 0) and set the clamp levels for IN2_

and IN3_ to +1.5V (CLEVEL2, 3 = 1) for Y Pb Pr filtering

(Figure 12) and set all clamp levels to 1V (CLEVEL_ =

0) for RGB filtering (Figure 13). A Y Pb Pr component

video-filter application requires three MAX7428s with

SYNCIO master-slave configuration. The MAX7428 pro-

cessing the Y signal has its SYNCIO configured as an

output, which in turn drives the SYNCIO inputs of the

other MAX7428s (Figure 14). For RGB video signal fil-

tering with a separate horizontal sync signal, configure

all MAX7428s for SYNCIO as an input (Figure 15).

14 ______________________________________________________________________________________

Share Link: