Horizontal Filter Locking Mechanism; Vertical Filters And Measurements; Primary Port Vertical Filter Measurements - Analog Devices ADV7850 Hardware Manual

Function
bg_param_lock
0 
1
bg_total_line_width[13:0], Addr 68 (HDMI), Address 0xE4[5:0]; Address 0xE5[7:0] (Read Only)
This readback displays the total number of pixels per line on the background measurement port. The background port total line width is
a horizontal synchronization measurement for the background HDMI port determined by bg_meas_port_sel[1:0]. The value represents
the total number of pixels in a line and is updated when an update request is made via bg_meas_req control. This measurement is valid
only when bg_param_lock is set to 1.
Function
bg_total_line_width[13:
0]
xxxxxxxxxxxxx
bg_line_width[12:0], Addr 68 (HDMI), Address 0xE2[4:0]; Address 0xE3[7:0] (Read Only)
This readback displays a value representing the number of active pixels in a line and is updated when an update request is made via
bg_meas_req. The background port line width is a horizontal synchronization measurement for the background HDMI port
determined by bg_meas_port_sel[1:0]. The value represents the number of active pixels in a line and is updated when an update request
is made via bg_meas_req control.
Function
bg_line_width[12:0]
0000000000000 
xxxxxxxxxxxxx

Horizontal Filter Locking Mechanism

7.24.4
The locking/unlocking mechanism of the HDMI horizontal filter is as follows:
• The HDMI horizontal filter locks if both of the following two conditions are met:
The DE transitions occur at the same pixel count for 8 consecutive video lines

The HSync transitions occur at the same pixel count for 8 consecutive video lines

• The HDMI horizontal filter unlocks if either of the two following conditions are met:
The DE transitions occur on different pixels count for 15 consecutive video lines

The HSync transitions occur on different pixels count for 15 consecutive video lines


Vertical Filters and Measurements

7.24.5
The ADV7850 integrates an HDMI vertical filter which performs measurements on the VSync of the HDMI stream on the selected port.
The ADV7850 also performs vertical measurements on the background port as selected by bg_meas_port_sel[2:0].These measurements
are available in the HDMI Map and can be used to determine the resolution of the incoming video data streams.

Primary Port Vertical Filter Measurements

7.24.6
The HDMI vertical filter performs the measurements described in this section on the HDMI port selected by hdmi_port_select[2:0].
The field 0 measurements are adequate to determine the standard of incoming progressive modes. A combination of field 0 and field 1
measurements should be used to determine the standard of interlaced modes.
Notes:
• The vertical measurements are valid only if
• The HDMI vertical filter is used solely to measure the vertical synchronization signals decoded from the HDMI stream. This
filter is not in the main path of the synchronization processed by the part and does not delay the overall HDMI data in to video
data out latency.
Rev. A May 2012
Description
Horizontal and vertical not locked when measurement taken for select background HDMI port
Horizontal and vertical locked when measurement taken for select background HDMI port
Description
Total number of pixels per line on background measurement port
Description
Number of active pixels per line on background measurement port
Number of active pixels per line on background measurement port
v_locked_raw is set to 1.
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ADV7850