TDA9209 datasheet(10/22 Pages) STMICROELECTRONICS

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TDA9209

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4.14 Power-on Reset

A power-on reset function is implemented on the

TDA9209 so that the I

2C registers have a deter-

mined status after power-on. The Power-on reset

threshold for a rising supply on VCCA (Pin 7) is

3.8 V (typ.) and 3.2V when the VCC decreases.

Figure 9. I2C Write Operation

4.15 Video detection (see Figure 10)

The video detection consists of three fast compa-

rators and a OR function.

The positive input of each comparator is connect-

ed to the input video pin (R, G, or B).

The negative inputs are connected together to a

reference voltage. This voltage is the threshold of

the comparators. The typical threshold voltage is

120 mV. The three comparator outputs are con-

nected to the OR inputs. Active Video output can

be inhibited by using bit 7 in Register 13 :

When AV output is validated, the AV output reach-

es 5V when at least one of the 3 video inputs gets

higher than 3.8V (typ.), and decreases to 0V if the

3 input voltages get lower than 3.2V (typ.).

Figure 10. Video Detection

SCL

SDA

ACK

I2C Slave Address

Start

Data Byte

ACK

Stop

R13b7 = 0

AV inhibited

R13b7 = 1

AV validated

120mV

R13b7=0

IN1

IN2

IN3

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