kv = 65535 / 13.4      # conversion from Volts to PWM
kw = 0.16*pi           # conversion from counts to rad/sec

V = 0

while(V < 13.4):
    fwd.duty_u16(int(V*kv))
    rev.duty_u16(0)
    sleep(0.5)
    Speed = N12*kw
    print('{: 7.4f}'.format(V), '{: 7.4f}'.format(Speed), N12)
    V += 0.1
 
print('Stop')
fwd.duty_u16(0)
rev.duty_u16(0)