Tmds Clock Activity Detection - Analog Devices ADV7850 Hardware Manual

bg_meas_req, Addr 68 (HDMI), Address 0x5A[5] (Self-Clearing)
This control is used in order to obtain the correct measurements of the selected background port. Setting this control sends a request to
update the synchronization parameter measurements of the currently selected background port. The port on which the measurement
will be made is selected by bg_meas_port_sel[1:0]. It is a self clearing control.
Function
bg_meas_req
0 
1
Note: After setting the self clearing BG_MEAS_REQ bit, the measurements of the TMDS frequency and video parameters of the
background ports are valid when
bg_meas_done_raw, IO, Address 0x8D[1] (Read Only)
This readback indicates the status of the background port measurement completed interrupt signal. When set to 1, it indicates that
measurements of the TMDS frequency and video parameters on the selected background port are completed.
Function
bg_meas_done_raw
0 
1
Note: This bit only informs the user that the measurement is complete and can be read back. One should ensure that
asserted so that the background parameter filters are locked and the measurement values are valid.

7.16 TMDS CLOCK ACTIVITY DETECTION

The ADV7850 provides circuitry to monitor TMDS clock activity on each of its four HDMI ports. The firmware can poll the appropriate
registers for TMDS clock activity detection and configure the ADV7850 as desired.
hdmi_mode, Addr 68 (HDMI), Address 0x05[7] (Read Only)
This readback indicates whether the stream processed by the HDMI core is a DVI or an HDMI stream.
Function
hdmi_mode
0 
1
bg_hdmi_mode, Addr 68 (HDMI), Address 0xEB[0] (Read Only)
This readback provides the HDMI/DVI mode status of the background port determined by bg_meas_port_sel[1:0] and is updated
continuously.
Function
bg_hdmi_mode
0 
1
tmds_clk_a_raw, IO, Address 0x6A[3] (Read Only)
This readback indicates the raw status of the Port A TMDS clock detection signal.
Rev. A May 2012
Description
No request to update selected background port synchronization parameter measurements
Requests update of selected background port synchronization parameter measurements
bg_meas_done_raw goes high.
Description
Measurements of TMDS frequency and video parameters of background port not finished or
not requested.
Measurements of TMDS frequency and video parameters of background port ready
Description
DVI mode detected
HDMI mode detected
Description
DVI mode detected on selected BG port
HDMI mode detected on selected BG port
153
ADV7850
bg_param_lock is