User manual

From my .sdc file
This is a mixture of what I originally entered and wizard generated text.
I copy and rename the file from another project. Give it the name of the
top file with the .sdc extension. This seems to be read and overwritten
automatically.
I had to split the CLOCK_25 line into two lines to make it fit here. Make it
back into one line if you use it.
# Clock constraints
create_clock -name "CLOCK_50" -period 20.000ns [get_ports {CLOCK_50}]
create_generated_clock -divide_by 2 -source [get_ports CLOCK_50]
-name "CLOCK_25" [get_registers CLOCK_25]
#create_clock -name "CLOCK_28" -period 35.714ns [get_ports {CLOCK_28}]
#create_clock -name "TD1_CLK27" -period 37.037ns [get_ports {TD1_CLK27}]
#create_clock -name "GPIO_1[10]" -period 25ns [get_ports {GPIO_1[10]}]
# Automatically constrain PLL and other generated clocks
derive_pll_clocks -create_base_clocks
EECS 452 – Fall 2014 Lecture 5 – Page 43/143 Tuesday – September 16, 2014