ADC SAR Overclocking Technique

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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

Simple trick allows to avoid PSoC Cteator timings limitations in ADC clocking.
1. We need to use external clocking.
2. We need to break direct clock path to ADC, so the Creator will not know about the exact clock frequency.
It could be done with any logic element such as AND, OR, NOT etc. 
In my case most suitable was Either Edge Detector.
At my setup with Master Clock 80 MHz, maximum achieved clock to ADC was 26.6 MHz. And it works, giving sample rate ~1.9 Msp/s.
Using this technique and double sampling I could digitize in real time Full HD video with  42 samples per string.
Some pictures attached.
And as usual you'll use it at your own risk.

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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

Could not embed images from the first attempt.

   

   

   

   

   

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted
        How many bits were the ADC setting and actual estimated?   
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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

Hello, odissey1

   

Both ADCs was set @8 bit. Actual values could be estimated with Rmax, Gmax and Bmax which represents max values on each color.

   

Also, as you could see, no color distortion occured. 

   

In this setup I guess dynamic range was 7 Bits/color

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

Do you have 2 interleaving ADCs or a single one?

   

What LCD update rate you got? 

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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

Yes two ADC with interleave(double-sampling). LCD works via SPI @40 MHz with 3-5 FPS(depends of graphic volume). LCD out is not the goal of the project. It's just for debug.

   

It is a prototype for single crystal ambilight like system.