Chip requirements: use appropriate functions, realizes the measurement of motor speed (unit: r/s)
1, the use of AD sampling analog voltage
2, AD sampling digital quantity through (produce AOUT DCIN), DA output to the motor drive the rotating
3, use the 8253 motor speed calculation (motor per round, CKM pins produce a pulse signal)
4, the use of 8255 pb mouth to speed value output to the LED, display BCD way (unit; R/s)