delay函数用于使程序暂停指定的毫秒数 。millis函数返回Arduino板启动后的毫秒数 。 micros函数返回Arduino板启动后的微秒数 。map函数可将一个数值从一个范围映射到另一个范围 。constrain函数用于将数值限制在指定的范围内 。random函数能指定范围内的随机数 。randomSeed函数设置随机数器的种子 。Serial.begin函数初始...
delay(1000); lcd.setCursor (0,1); // go to start of 2nd line lcd.print(" "); lcd.print(millis()); delay(1000); lcd.setBacklight(LOW); // Backlight off delay(250); lcd.setBacklight(HIGH); // Backlight on delay(1000); } 实验三温湿度传感器: 目标效果:屏幕显示当前的温度和湿度...
但是DHT22模块数据传输需要一定的间隔,Adafruit提供的DHT xx库中的example使用了delay函数。我们正常的第一想法是直接将两个功能模块拼接,但会发现数码管数字显示实时温度值时候亮度分配不均,不够完美。于是我想起了http://Arduino.cc中推荐使用的 millis ()计时函数,这个函数规定一个时间间隔,每隔一段时间获取新的温...
原因是PWM输出所使用的内部时钟,millis()与delay()两函数也在使用。所以要注意使用5,6号端口时,空占比要设置的稍微低一些,或者会产生5,6号端口无法输出完全关闭的信号。PWM(Pulse-width modulation)脉宽调制PWM是使用数字手段来控制模拟输出的一种手段。使用数字控制产生占空比不同的方波(一个不停在开与关之间切换...
Delay statements are great and all, especially for their simplicity, but they can really put a damper on things when trying to multitask your Arduino. Forget delay and hop on the millis() train! Delay statements are great and all, especially for their simplicity, but they can really put a...
–With 20Mhz, will the delay’s and millis work propertly? Thanks very much for your support, I would update on my progress. Reply maniacbug November 19, 2012 at 2:26 pm If it’s your first time with electronic design, I recommend sticking with the tried-and-true formulations. In...
using function defined at the end of the codecheckLedState();}voidloop(){// read the state of the switch into a local variableintreading=digitalRead(buttonPin);if(reading!=lastButtonState){// reset the debouncing timerlastDebounceTime=millis();}if((millis()-lastDebounceTime)>debounceDelay){...
/** * 处理主题消息 * @param timeout 超时时间 */ void Adafruit_MQTT::processPackets(int16_t timeout) { uint32_t elapsed = 0, endtime, starttime = millis(); while (elapsed < (uint32_t)timeout) { // 获取主题消息内容 Adafruit_MQTT_Subscribe *sub = readSubscription(timeout - elapsed...
Meanwhile, Timer2 might be producing the "test signal". So there are no timers free and we cannot use the normal Arduino functions delay(), millis(), etc. The code for the frequency counter is based on the excellentweb pagebyNick Gammon. ...
}voidloop(){// Check whether we keep receving data, or we have a connection between the two modulescurrentTime =millis();if( currentTime - lastReceiveTime >1000) {// If current time is more then 1 second since we have recived the last data, that means we have lost connectionresetData...