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Hi,
I am trying to sample an 80 Mhz video signal from an ADC. Obviously, my 12 Mhz LPC can't handle this. Is there a way to slow it down to take a full frame at a time, and ignore the ones it can't grab.
My only other option is a Xilinx chip to buffer the data, and allow the LPC to fetch it from Xilinx as fast as it can.
The only diigital way to slow down a video signal is by sampling it fast enough and then replay the samples at a lower speed. Obviously a solution that manages to sample at the required speed may be able to continue to record if it just have a fast enough (and large enough) memory medium to deliver the samples to.
Analog slowdown is very problematic at these frequencies, since 80MHz is way faster than the bandwidth of a normal VHS video, and higher-bandwidth analog video solutions gets very, very expensive.
What is the video signal you want to digitize, and what do you want to do with the digitized info? A normal flat monitor with VGA connector has to sample the analog data at a very high sample rate. There are a number of high-speed ADC available specifically for that kind of signals, but to be able to store the sampled data, you need dedicated high-bandwidth memory. Yuor average microcontroller can not pick upp data at that speed.
I am using a TVP7000 to digitize RGB VGA, at a resolution up to 1280x1024.
I think what I will have to do is configure a CPLD to buffer the data, and the micro can sample the CPLD at a frame rate it can handle.
But what is your goal? A single-frame freeze or?
I need a video stream. Obviously not at a high frame rate, but usable.
No way are you going to pass anything resembling a usable video stream through a CPU running at 12 MHz.
1280x1024x(R8,G8,B8)@10fps is still more than 30 MBytes/s, and video at less than 10 frames per second is unusable.