a question about sourc e synchronous interface - Skew Approach

Hi Rysc,

my question is:

what determine the parameters (2.0/-1.0) in "data may change only within a window "?

i know that 2.0 is determined by setup parameter of extern device and 1.0 is determined by hold parameter of extern device in "data can't change within a window". (of course it is based on skew approach).

set_output_delay -max 2.0 -clock CLKQ [get_ports DATAOUT]

set_output_delay -min -1.0 –clock CLKQ [get_ports DATAOUT]

but what determine the parameter (2.0/-1.0)in below constraint in "data can change only within a window"? how these two parameters are got by calculation? here assume external latch edge is the same edge as launch edge - source synchronous interface.

set_multicycle_path 0 -setup -to [get_ports DATAQ]

set_multicycle_path -1 -hold -to [get_ports DATAQ]

set_output_delay -max -1.0 -clock CLK_STROBE [get_ports DATAQ]

set_output_delay -min +2.0 -clock CLK_STROBE [get_ports DATAQ]

Could you pls provide more details so as to help me to understand it?

thanks

BR,

cxyisher