#NET "BTN_EAST" LOC = "H13" | IOSTANDARD = LVTTL | PULLDOWN ;
#NET "BTN_NORTH" LOC = "V4" | IOSTANDARD = LVTTL | PULLDOWN ;
NET "sys_res" LOC = "K17" | IOSTANDARD = LVTTL | PULLDOWN ;
-#NET "BTN_WEST" LOC = "D18" | IOSTANDARD = LVTTL | PULLDOWN ;
+NET "btn_a" LOC = "D18" | IOSTANDARD = LVTTL | PULLDOWN ;
# ==== Clock inputs (CLK) ====
NET "CLK_50MHZ" LOC = "C9" | IOSTANDARD = LVCMOS33 ;
# Define clock period for 50 MHz oscillator (40%/60% duty-cycle)