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neelmehta89
Visitor
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Registered: ‎04-06-2012

Input pin which detects narrow pulses on Spartan 3E Starter Kit

I have data encoded as 5 MHz (200ns) pulses. So, every 200 ns, I will get short pulses of 5ns duration (if data transmitted is 1) or no pulse (if data transmitted is 0). This data is transmitted via the SMA connector (C9) on the Spartan 3E starter kit, passes through some external circuitry (communication circuit) and is received back to the FPGA. I want to test if the data transmitted is same as data received and display the error on the LCD.

 

So, what pin on the FPGA kit should I use as an input pin in order to detect the 4ns-5ns pulses every 200ns?

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gszakacs
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Registered: ‎08-14-2007

I would route the signal to a global clock input.  That way if you want to sample the pulses

by toggling a flip-flop when a pulse arrives you will be able to easily route the signal to a BUFG.

If you instead try to sample the input, you would need a pretty high speed sampling clock to

avoid missing pulses.  In any case you can use a global clock input pin even if you decide to

sample the signal on another clock.

 

-- Gabor

-- Gabor
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sathvika
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Registered: ‎04-25-2014

 
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