loopback.ucf

硬件平台为Xilinx Spartan3e

NET "clk" TNM_NET = "clk";
TIMESPEC "TS_clk" = PERIOD "clk" 20 ns HIGH 50 %;
OFFSET = IN 7 ns BEFORE "clk"  ;
OFFSET = OUT 7.5 ns AFTER "clk"  ;


NET "clk"  LOC = "c9" | IOSTANDARD = LVCMOS33 ;
NET "leds<0>"  LOC = "f12" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<1>"  LOC = "e12" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<2>"  LOC = "e11" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<3>"  LOC = "f11" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<4>"  LOC = "c11" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<5>"  LOC = "d11" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<6>"  LOC = "e9" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "leds<7>"  LOC = "f9" | IOSTANDARD = LVTTL  | SLEW = SLOW  | DRIVE = 8 ;
NET "rs232_rx"  LOC = "R7" | IOSTANDARD = LVTTL ;
NET "rs232_tx"  LOC = "M14" | IOSTANDARD = LVTTL ;
NET "rst"  LOC = "v16" | IOSTANDARD = LVTTL  | PULLDOWN ;
NET "switches<0>"  LOC = "l13" | IOSTANDARD = LVTTL  | PULLUP ;
NET "switches<1>"  LOC = "l14" | IOSTANDARD = LVTTL  | PULLUP ;
NET "switches<2>"  LOC = "h18" | IOSTANDARD = LVTTL  | PULLUP ;
NET "switches<3>"  LOC = "n17" | IOSTANDARD = LVTTL  | PULLUP ;
NET "switches<4>" IOSTANDARD = LVTTL ;
NET "switches<5>" IOSTANDARD = LVTTL ;
NET "switches<6>" IOSTANDARD = LVTTL ;
NET "switches<7>" IOSTANDARD = LVTTL ;