サーボモーターの動作確認(M5stack gray)

/*******舵机测试程序*******
 * Arduino型号：Arduino UNO
 **************************/
#include <m5stack.h>    // M5stack needs this module
int servopin=2;
int pulsewidth;
void servo(int myangle)
{
 for (int i = 0; i < 20; i ++)  // i is used to make moving time, since this source does not use library.
 {
pulsewidth=map(myangle,0,180,500,2500);
digitalWrite(servopin,HIGH);
delayMicroseconds(pulsewidth);
digitalWrite(servopin,LOW);
delay(20-pulsewidth/1000);
 }
}
void setup()
{
 pinMode(servopin,OUTPUT);
 M5.begin();
 M5.Lcd.fillScreen(BLACK); //Set the screen background color to black. 
 M5.Lcd.setTextColor(GREEN , BLACK); //Sets the foreground color and background color of the displayed text.  
 M5.Lcd.setTextSize(2);  //Set the font size.  
}
void loop()
{
 M5.Lcd.setCursor(0, 70);
 M5.Lcd.printf("servo_motor drive");
 servo(0);
 delay(500);
 servo(180);
 delay(500);
}