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ADV7619 TMDSFREQ Accuracy

Question asked by rpmarchand Employee on Sep 4, 2015
Latest reply on Sep 4, 2015 by mattp

Hello,

 

i'm using the ADV7619 to receive 1080p60 video and i'm looking to use the TMDS frequency measurement readings from the part to detect the video format.  I have read through UG-237 and i have made sure to follow table 9. 

 

I am observing that the TMDS frequency read back is quite close but slightly inaccurate, for example:  inputting 1080p60 vdieo the TMDS frequency is confirmed to be 1.485GHz. I am expect to reading back TMDSFREQ = 148 and TMDSFREQ_FRAC = 64 (64/128 = 5MHz).  What i observe is that i am reading back TMDSFREQ correctly, but TMDSFREQ_FRAC is reading back as 62 (or 0.484375MHz). 

 

I am checking on my crystal but i was wondering if you had an expectation of how accurate the TMDSFREQ read back should be for the ADV7619?  Or if you had any other recommendations to review that might impact these values. 

 

Thanks!

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