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Altera_Forum
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10 years ago

Time Delay generation in EPM1270T144C5N CPLD

I have a signal, that is input to EPM1270T144CN. That is not a periodic signal. There are only two pulses. I want to delay them by 25 nsec at the output. Is there a way to do this, as per required ti...
Altera_Forum's avatar
Altera_Forum
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10 years ago

From pin-to-pin, probably the quickest way is to do:

set_max_delay -from [get_pins {din_a din_b}] -to [get_pins {delayed_a delayed_b}] 25.0

set_min_delay -from [get_pins {din_a din_b}] -to [get_pins {delayed_a delayed_b}] 25.0

Now, that's saying it has to be a perfect 25ns, which is impossible to dial in that precise and impossible over PVT, so to actually meet timing you need to expand them:

set_max_delay -from [get_pins {din_a din_b}] -to [get_pins {delayed_a delayed_b}] 33.33

set_min_delay -from [get_pins {din_a din_b}] -to [get_pins {delayed_a delayed_b}] 16.66

This relies on the router adding delay to meet your minimum requirement, and to be honest, I'm not sure if it does for that device, as I've never tried it.