时序分析.txt

sdram读写

取Tdata-pcb=0.125ns,Tclk-pcb=0.125ns;


input delay：
SDRAM时钟sdram_clk的上升沿为launch edge，而FPGA时钟clk_100m上升沿为latch edge。那么有：-2ns<tco<4.5ns

input max delay = 4.5ns+0.125ns-0.125ns=4.5ns
input min delay = -2ns+0.125ns-0.125ns=-2ns

output delay:
FPGA时钟clk_100m上升沿为launch edge,而SDRAM时钟sdram_clk的上升沿为latch edge。那么有：Tsu=1.5ns,Th=1ns

output max delay = 1.5ns+0.125ns-0.125ns=1.5ns
output min delay = -(1ns-0.125ns-0.125ns)=-0.75ns