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Clamping error with digital sources
unexpected clamping effect on digital sources
A screencapture is attached.
1. Digital fine clamp is enabled by default script.
2. With following conditions, clamping will affect unexpectedly.
non-standard timing such as wider positive tri-level in digital source. (in case of 1080/60i from DVI)
non-standard pedestal such as filled with 0 or 255 during blanking period
Disable digital fine clamping by set 0x6C = 0 in CP block.
ADV7842 UG-214 Hardware User Guide 10.2 CLAMP OPERATION
Normally, digital fine clamp has no effect on digital sources such as DVI or HDMI, since these signals come with stable digital pedestal.
In Hardware User Guide, there is NO speicific information regarding bit4 of 0x6C, which should be explained by Analog Devices.
Applys to :
ADV7842 (CP 0x6C)
ADV7611 (CP 0x??)