diff --git a/README.md b/README.md
index 5fac71e..725196d 100644
--- a/README.md
+++ b/README.md
@@ -155,3 +155,4 @@ Test the prototype.
     [ ] route 16-channel ADC
     [x] move 8 LEDs a bit down and right
     [x] let SD_CLK go to FPGA clock capable pin: swap SD_CLK and SD_D2 pins 
+    [ ] additional 2 differential lines for US2