DocID024813 Rev1

5/31

HDMI2C2-14HD

Application information

31

2

Application information

2.1

CEC line description

The CEC bus is described in the HDMI standard as the Consumer Electronics Control. It

provides control functions between all the various audiovisual equipments chained in the

user's environment.

The CEC block integrated in the HDMI2C2-14HD implements a level shifter, shifting the

can be as low as 1.8 V. The Figure 2 shows the functional diagram of the integrated CEC

block.

Figure 2. CEC functional block diagram

pin is put in high impedance mode (open circuit) protecting the circuitry and the application

against hazardous backdrive.

The Figure 3 illustrates the normal operating mode of the CEC functional block when either

the IC from the source on the sink drives the communication.

Figure 3. CEC simplified

CEC_IC

VDD_CEC_IC

CEC

VDD_CEC

VDD_CEC_IC

VDD_CEC

CEC

driver

UVLO

Ctrl

circuit

Enable

1

3

5

7

9

11

12

13

14

15

16

17

18

19

2

4

6

8

10

HDMI

connector

decoupling

capacitance

V

DD_CEC_IC

CEC_IC

CEC

V

Tup_CEC

V

DD_CEC_IC

CEC_IC

V

DD_CEC

CEC

V

IL_CEC_IC

V

IH_CEC_IC

Block in high

impedance

Level shifting

Source IC drives

Sink drives through HDMI cable

Block in high

impedance

Block in high

impedance

Level shifting

Block in high

impedance

t

t

t

t

10%

90%

t

FALL_CEC

t

RISE_CEC