Question

Consider a disk mounted on a DC motor that has a variable speed. There are 4 small holes (hl, h2, h3
and h4) on the disk (90 degrees apart). In each revolution, the system generates four pulses (one pulse
against each hole). The disk of motor is connected with 8051microcontroller such that pulse of each hole is sensed at
(pin P3.4while revolving. Speed of the motor is reasonably large such that the pulses are of very short
duration.
Write an assembly language program to calculate speed of motor in RPM (revolutions per minute).
Maximum value of speed can be 2400RPM, Store the lower byte of answer in R0 and higher in RI of
banko. (Hint: First caiculate number of revolutions per second and then find speed).

Answer 1