Why does the Intel® Quartus® Prime Timing Analyzer ignore clocks with a period greater than 2147483ns?

Description

Due to the integer limit in the Intel® Quartus® Prime Pro and Standard Edition software, you may see that clocks created with a period greater than 2147483ns is ignored.

Constraint: 

create_clock -name clkA -period 2147484 [get_ports clk] 

Warning:

Ignored create_clock: Time value "2147484" is not valid

Ignored create_clock: Option -period: Invalid clock period  

Resolution

To work around this limitation, use a clock period equal to or smaller than 2147483 ns. The size of the period variable is 32 bits ranging from −2147483648ps to 2147483647ps.

The create_clock constraint accepts values in nanoseconds by default but stores them as picoseconds. Therefore, 2147484ns is stored as 2147484000ps, which exceeds the limit of a 32-bit integer.