set PERIOD_CLK               1    # 1 nSec is period of that clock

set INPUT_DELAY_MARGIN    0.60
set OUTPUT_DELAY_MARGIN   0.40

set CLK_IN_DELAY [expr { $PERIOD_CLK * $INPUT_DELAY_MARGIN }]
set PCLK_OUT_DELAY  [expr { $PERID_PCLK * $OUTPUT_DELAY_MARGIN }]

# input delay is given to din_i pin/port
set_input_delay $CLK_IN_DELAY  -clock $CLK  [get_ports din_i]

# output delay is given to dout_o pin/port
set_output_delay $CLK_OUT_DELAY     -clock $CLK     [get_ports dout_o]