Inquiry i.MX8M HDMI_HPD Voltage level (input) and spec.

[andychien]

Dear Sir,

We checked i.MX8M documents and HDMI_HPD on power group HDMI_AVDDIO. (type is 1.8V)

We measured HDMI_HDP voltage is 4.88V on i.MX8M MEK.

Could you help check what spec. on HDMI_HPD? (max. voltage)

Thanks a lot,

[andychien]

Dear Artur,

thanks a lot for your reply.

Customer want to know this pads input spec. (min voltage, type voltage, max voltage)

could you provide it?

thanks,

[art · Accepted solution]

The HDMI Specification 1.4b, which the HDMI Specification 2.0a document refers to, says the following.

"4.2.9 Hot Plug Detect Signal (HPD)

The ground reference for the Hot Plug Detect signal is the DDC/CEC Ground pin.

Table 4-38 Required Output Characteristics of Hot Plug Detect Signal

Item                                                   Value

High voltage level (Sink)                   Minimum 2.4 Volts, Maximum 5.3 Volts
Low voltage level (Sink)                   Minimum 0 Volts, Maximum 0.4 Volts
Output resistance 1000 ohms ±20%

Table 4-39 Required Detection Levels for Hot Plug Detect Signal

Item                                                     Value

High voltage level (Source)                 Minimum 2.0 Volts, Maximum 5.3 Volts
Low voltage level (Source)                 Minimum 0 Volts, Maximum 0.8 Volts

Note that many Sink devices simply connect the HPD signal to the +5V Power signal through a 1000 ohm resistor. It may therefore be necessary for a Source to pull-down the HPD signal in order to reliably differentiate between a floating (disconnected) HPD and a high voltage level HPD signal. "

Best Regards,

Artur

[art]

The HDMI_HPD signal of the i.MX8M processor is the analog PHY input signal, it meets the HDMI 2.0a specification, so, it can sustain the +5V input signal.

Have a great day,
Artur

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