diff --git a/matlab/dAUIS.m b/matlab/dAUIS.m
index 18b8fb2..e0aa5f2 100644
--- a/matlab/dAUIS.m
+++ b/matlab/dAUIS.m
@@ -1,7 +1,15 @@
 #determineArduinoUnoInterruptSettings.m 
-function [output] = dAUIS.m(input)
-  #input from 0 to 65535
-  #output from 0 to 255
-  #using crossproduct
-  output=(input*255)/65535;
+function [p] = dAUIS.m(f)
+  prescaler = [1,8,64,256,1024]
+  for i=1:5
+    cmr = (16000000/prescaler(i)*f) - 1;
+    display("prescaler: ");
+    display(prescaler(i));
+    if cmr < 256
+      display("8 bit");
+    endif
+    if cmr > 255 && cmr < 65536 
+      display("16 bit");
+    endif
+  endfor
 endfunction