C
@fmcq 在 openmv连接超声波模块，提示pix format错误 中说：
mport time,utime,pyb
from pyb import Pin
wave_echo_pin = Pin('P7', Pin.IN, Pin.PULL_NONE)
wave_trig_pin = Pin('P8', Pin.OUT_PP, Pin.PULL_DOWN)
wave_distance = 0
tim_counter = 0
flag_wave = 0
#超声波启动
def wave_start():
wave_trig_pin.value(1)
utime.sleep_us(15)
wave_trig_pin.value(0)
#超声波距离计算
def wave_distance_calculation():
#全局变量声明
global tim_counter
#频率f为0.2MHZ 高电平时间t=计数值1/f
wave_distance = tim_counter5*0.017
#输出最终的测量距离（单位cm）
print('wave_distance',wave_distance)
#超声波数据处理
def wave_distance_process():
global flag_wave
if(flag_wave == 0):
wave_start()
if(flag_wave == 2):
wave_distance_calculation()
flag_wave = 0
#配置定时器
tim =pyb.Timer(1, prescaler=720, period=65535) #相当于freq=0.2M
#外部中断配置
def callback(line):
global flag_wave,tim_counter
#上升沿触发处理
if(wave_echo_pin.value()):
tim.init(prescaler=720, period=65535)
flag_wave = 1
#下降沿
else:
tim.deinit()
tim_counter = tim.counter()
tim.counter(0)
extint.disable()
flag_wave = 2
#中断配置
extint = pyb.ExtInt(wave_echo_pin, pyb.ExtInt.IRQ_RISING_FALLING, pyb.Pin.PULL_DOWN, callback)
while(True):
wave_distance_process()
time.sleep(100)
print('wave_distance',wave_distance)
想问一下，这个代码最后是怎么实现超声波测距的吗