Forum Discussion
Altera_Forum
Honored Contributor
15 years ago --- Quote Start --- i have an output bus, which has to provide new data 15..20ns after the rising edge of the input clock. clock period is 61ns. with the classic timing analyzer, i had TCO defined as 20ns and MTCO as 15ns. how do i have to define this using set_output_delay? defining this requirement as Tsu and Th results in: Tsu = 61ns - 20ns = 41ns Th = 15ns but i do not understand how to define this using the set_output_delay construct. --- Quote End --- with classic analyser, for your case I will set minimum Tco to 15 and maximum Tco to period-20. With Timequest, my current understanding from altera documents is this: maximum delay = setup of dest. register (i.e. 20 ns if we assume equal clk/data delay). and minimum delay is -hold time (-15ns again if we assume equal data/clk delay). However that applies to clk going out with data. In your case you refer to input clk and thus you should adjust the figures as clk/data delay now is double even on equal trace.