Edid_Tries Control; Edid_Reread Control; Hdcp Handling; One Sink And No Upstream Devices - Analog Devices ADV7850 Hardware Manual

EDID_TRIES Control

13.13.4
edid_trys[3:0] can be used to set the number of times the Tx EDID/HDCP controller tries to read the sink EDID after a failure. Each time
an EDID read fails with an I
value 0, the Tx EDID/HDCP controller will not attempt to read the EDID until
used if a sink asserts high its HPD signal before the DDC bus is ready, resulting in several NACKs as the ADV7850 attempts to read the
EDID.
edid_trys[3:0], Addr B8 (Main), Address 0xC9[3:0]
This control is used to set the maximum number of times that the EDID read will be attempted if unsuccessful. Reading the EDID
begins upon setting this register and on powerup.
Function
edid_trys[3:0]
0011 

EDID_REREAD Control

13.13.5
If the EDID data from the sink is read in and the host determines that the data needs to be reread,
and the current segment set via
that one EDID checksum read from the sink is invalid.
Note: It is also possible to reread the EDID from the sink by toggling the Tx core power-down
edid_read_en, Addr B8 (Main), Address 0xC9[4]
Reread the current segment if toggled from 0 to 1 for 10 times consecutively.
Function
edid_read_en
0 <<
1

13.14 HDCP HANDLING

One Sink And No Upstream Devices

13.14.1
The ADV7850 has a built-in controller, the Tx EDID/HDCP controller, which handles HDCP transmitter states, including handling
downstream HDCP repeaters. To activate HDCP from a system level, the host controller needs to set
This informs the ADV7850 that the video stream it outputs should be encrypted. The ADV7850 takes control from there and implements
all the remaining tasks defined by the HDCP 1.4 specification.
Before sending audio and video, the BKSV of the downstream sink should be compared with the revocation list compiled by managing
System Renewability Messages (SRMs) provided on the source content (for example. DVD, Blue-ray Disc), and the
interrupt should be cleared. After the HDCP link is established between the ADV7850 and the downstream sink, the system controller
should monitor the status of HDCP by reading
hdcp_error_interrupt is set to 1 if there is an error relating to the controller. The meaning of the error can be determined by checking
hdcp_controller_error[3:0].
bksv_flag_intr, Addr 72 (Main), Address 0x97[6]
BKSV Flag interrupt status
Rev. A May 2012
C Not Acknowledged (NACK), this value of
2
Description
Default
edid_segment[7:0] will be reread. Rereading the sink EDID may be useful, for example, if the host finds
Description
Default value
Request the EDID/HDCP controller to read the EDID
enc_on
edid_trys[3:0]
edid_trys[3:0]
every two seconds. The Tx EDID/HDCP controller error interrupt activates and
382
is decremented. Once edid_trys[3:0]
is set to a value other than 0. This could be
edid_read_en can be set from 0 to 1,
system_pd bit from 0 to 1.
hdcp_desired
ADV7850
reaches the
to 1 and enc_on to 1.
bksv_flag_intr