Analog Devices ADV8005, Справочник по аппаратуре

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ADV8005 Hardware Reference Manual UG-707
pre_en_clk , TX2 Main Map, Address 0xF480[0]
Enable clock channel
Function
pre_en_clk Description
1 (default) Enabled 0 = Disabled
To disable a TMDS output, it is recommended to follow this sequence:
1. Disable the charge injection for the channel
2. Disable the predriver for the channel
To enable a TMDS output, the opposite sequence should be followed:
1. Enable the predriver for the channel
2. Enable the required charge injection for the channel
In summary, the charge injection should only be enabled while the predriver is also enabled.
6.17. HDMI TX SOURCE TERMINATION
When an ADV8005 HDMI Tx output is connected to a sink device, the capabilities of the sink device’s receiver must first be considered. If the
sink device is limited to receiving a maximum TMDS clock frequency less than or equal to 165 MHz, the source termination must be disabled
in the
ADV8005 Tx connected to that sink device.
If the sink device can receive a TMDS clock frequency above 165 MHz, then the TMDS clock frequency of the
ADV8005 HDMI Tx connected
to that sink will dictate what source termination settings are used. In this case, the Tx source termination settings must be configured as follows:
•
ADV8005 Tx source termination disabled if the ADV8005 Tx TMDS clock frequency is less than or equal to 165 MHz
•
ADV8005 Tx source termination enabled if the ADV8005 Tx TMDS clock frequency is greater than 165 MHz
Therefore, for 4k x 2k, Tx source termination should be enabled on the
ADV8005 HDMI Tx output. To disable the source termination, a manual
over-ride must be enabled. The manual over-ride value is an open-circuit if the control is set to 0.
Figure 109 provides an overview of the ADV8005 HDMI Tx source termination requirements.
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