Fix pin assigments on ecp5 demo.

Also, because the USB clock autosuspends, change the demo so that
btn4 slows down the effect rather than starts it, so it's more
obvious that the demo is working.

Signed-off-by: Thomas Daede <daede003@umn.edu>

examples/ecp5_evn/blinky.v

diff --git a/examples/ecp5_evn/blinky.v b/examples/ecp5_evn/blinky.v
index 5730865..595e5dd 100644
--- a/examples/ecp5_evn/blinky.v
+++ b/examples/ecp5_evn/blinky.v
@@ -6,7 +6,7 @@
     reg dir = 0;
 
     always@(posedge clk) begin
-    ctr <= btn ? ctr : (dir ? ctr - 1'b1 : ctr + 1'b1);
+    ctr <= dir ? ctr - 1'b1 - btn: ctr + 1'b1 + btn;
         if (ctr[ctr_width-1 : ctr_width-3] == 0 && dir == 1)
             dir <= 1'b0;
         else if (ctr[ctr_width-1 : ctr_width-3] == 7 && dir == 0)

examples/ecp5_evn/ecp5evn.lpf

diff --git a/examples/ecp5_evn/ecp5evn.lpf b/examples/ecp5_evn/ecp5evn.lpf
index aaa9f28..bd32c6d 100644
--- a/examples/ecp5_evn/ecp5evn.lpf
+++ b/examples/ecp5_evn/ecp5evn.lpf
@@ -4,14 +4,14 @@
 LOCATE COMP "btn" SITE "P4";
 IOBUF PORT "btn" IO_TYPE=LVCMOS33;
 
-LOCATE COMP "led[0]" SITE "B17";
-LOCATE COMP "led[1]" SITE "A17";
-LOCATE COMP "led[2]" SITE "C17";
-LOCATE COMP "led[3]" SITE "B18";
-LOCATE COMP "led[4]" SITE "A18";
-LOCATE COMP "led[5]" SITE "B19";
-LOCATE COMP "led[6]" SITE "A12";
-LOCATE COMP "led[7]" SITE "F16";
+LOCATE COMP "led[0]" SITE "A13";
+LOCATE COMP "led[1]" SITE "A12";
+LOCATE COMP "led[2]" SITE "B19";
+LOCATE COMP "led[3]" SITE "A18";
+LOCATE COMP "led[4]" SITE "B18";
+LOCATE COMP "led[5]" SITE "C17";
+LOCATE COMP "led[6]" SITE "A17";
+LOCATE COMP "led[7]" SITE "B17";
 
 IOBUF PORT "led[0]" IO_TYPE=LVCMOS33;
 IOBUF PORT "led[1]" IO_TYPE=LVCMOS33;