1. Quadrature Shaft Encoders
Determine the net rotation

9. State Diagram 00 CW
CCW 01 10 11

10. I. Count up for CCW – Down for CW
If (analog(2) > && state == 01)
cnt++ ; state=11;
If (analog(2) > && state == 00)
cnt-- ; state=10;
If (analog(2) < && state ==10)
cnt++ ; state=00
If (analog(2) < && state == 11)
cnt-- ; state=01;

11. II. Count up for CCW – Down for CW
If (analog(3) > && state == 00)
cnt++ ; state=01;
If (analog(3) > && state == 10)
cnt-- ; state=11;
If (analog(3) < && state ==11)
cnt++ ; state=10
If (analog(3) < && state == 01)
cnt-- ; state=00;