Hot Plug Assert - Analog Devices ADV7850 Hardware Manual

dis_cable_det_rst, Addr 68 (HDMI), Address 0x48[6]
This control is used to disable the reset effects of cable detection. dis_cable_det_rst should be set to 1 if the +5 V pins are unused and left
unconnected.
Function
dis_cable_det_rst
0 
1

7.3 HOT PLUG ASSERT

The ADV7850 features hot plug assert (HPA) controls for its four HDMI ports. The purpose of these controls and their corresponding
output pins is to communicate to an HDMI transmitter that the E-EDID connected to the DDC bus can be accessed.
Note: In order to comply with the required output characteristics of Section 4.2.9 "Hot Plug Detect Signal" of the HDMI 1.4 specification,
the output resistance on the HPA pins must be 1000 Ohm +/-20%. This may easily be implemented by connecting the HPA line to the
corresponding +5 V power signal through a 1000 Ohm resistor.
hpa_manual, Addr 68 (HDMI), Address 0x6C[0]
This control is used to manually enable the Hot Plug Assert output pins. By setting this bit, any automatic control of these pins is
disabled. Manual control is determined by the hpa_man_value_x (where X = A, B, C or D).
Function
hpa_manual
0
1 
hpa_man_value_a, IO, Address 0x20[7]
This control is used to set the value of HPA on Port A. It is only valid if hpa_manual is set to 1.
Function
hpa_man_value_a
0 
1
hpa_man_value_b, IO, Address 0x20[6]
This control is used to set the value of HPA on Port B. It is only valid if hpa_manual is set to 1.
Function
hpa_man_value_b
0 
1
hpa_man_value_c, IO, Address 0x20[5]
This control is used to set the value of HPA on Port C. It is only valid if hpa_manual is set to 1.
Rev. A May 2012
Description
Reset HDMI section if 5 V input pin corresponding to selected HDMI port (e.g. RXA_5V for port
A) inactive
Do not use 5 V input pins as reset signal for HDMI section
Description
HPA takes its value based on hpa_auto_int_edid
HPA takes its value from hpa_man_value_x
Description
0 V applied to HPA_A pin
High level applied to HPA_A pin
Description
0 V applied to HPA_B pin
High level applied to HPA_B pin
138
ADV7850