i use 8 slot encoder.
after googling few minutes. i add this code into usbdemo
Code:
     COUNT PORTA.2,100,speed
     speed = speed * 10 * 60 / 8
     rpm[0] = speed / 1000 // 10
     rpm[1] = speed / 100 // 10
     rpm[2] = speed / 10 // 10
     rpm[3] = speed // 10
     rpm[4] = 0
     rpm[5] = 0
     rpm[6] = 1
     rpm[7] = 1
     
@   SendUSB _rpm