2.3

HEAC link and HPD line description

The HDMI2C1-6C1 proposes a unique solution to manage and to protect both the HEAC and the HPD link. The

Figure 7 shows an overview of the function diagram of the integrated block.

Figure 7. HEAC / HPD utility functional block diagram

HPD

HPD_IC

Utility

HDMI

ASIC

or

IC

VDD_IC

matching

Utility / HEAC+

HPD / HEAC-

HEAC+

HEAC-

VDD_IC

HDMI

connector

This block simplifies the design and the PCB layout of the HPD + HEAC functions. Simply connect the two pins

from the HDMI connector to one side of the device, and then use the three dedicated outputs on the other side of

the device to manage separately the HPD and the HEAC links.

Note that HEAC- and HEAC+ must be kept nonconnected when unused (to avoid connecting to GND when

unused).

Both HPD and utility inputs (cable side) integrate a protection against ESD, which is compliant with the

IEC61000-4-2 standard, level 4 (8 kV contact).

HPD line description

The HPD line is described in the HDMI standards as the hot plug detect function. This line is used by the source

device in order to detect if a sink device is connected through an HDMI cable.

The integrated HPD block is pulling down the line via a current source. When the input voltage is detected to be

higher than a threshold level, the signal is converted in a high state level on the ASIC side, at the voltage level of

the ASIC power supply VDD_IC. Otherwise, the CEC_IC pin remains in low state.

The Figure 8. Simplified view of the electrical parameters of the HPD block show the electrical parameters

relevant to the HPD block and specified by the Table 6. HPD, HEAC, and utility line electrical characteristics(Tamb

= 25 °C, VDD_5V = 5 V, unless otherwise specified).

HDMI2C1-6C1

HEAC link and HPD line description

DS9943 - Rev 4

page 7/22