乐趣为王

买东西的地方给的kuaipan的地址，但是貌似关闭分享功能了。去淘宝找了一下卖类似东东的网店，终于发现一家直接把代码贴上来了。我试验了一下，可用。纯属没地方放，另外给搜索过来的朋友做个参考，整段代码贴上来当做笔记。1602应该是四线模式，几个按键应该是模拟方式，也就是不支持多键同时按下。RST键会直接RESET。

#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 13, 9, 4, 5, 6, 7);

char msgs[5][16] = {"Right Key OK ",
                    "Up Key OK    ",              
                    "Down Key OK  ",
                    "Left Key OK  ",
                    "Select Key OK" };

int adc_key_val[5] ={50, 200, 400, 600, 800 };
int NUM_KEYS = 5;
int adc_key_in;
int key=-1;
int oldkey=-1;

void setup() {
  // put your setup code here, to run once:
  lcd.clear();
  lcd.begin(16, 2);
  lcd.setCursor(0,0);
  lcd.print("ADC key testing");
}

void loop() {
  // put your main code here, to run repeatedly:
  adc_key_in = analogRead(0);    // read the value from the sensor
  key = get_key(adc_key_in);  // convert into key press
 
  if (key != oldkey)   // if keypress is detected
   {
    delay(50);  // wait for debounce time
    adc_key_in = analogRead(0);    // read the value from the sensor
    key = get_key(adc_key_in);    // convert into key press
    if (key != oldkey)   
    {  
      lcd.setCursor(0, 1);
      oldkey = key;
      if (key >=0){
           lcd.print(msgs[key]);             
      }
    }
  }
delay(100);
}

// Convert ADC value to key number
int get_key(unsigned int input)
{
    int k;
  
    for (k = 0; k < NUM_KEYS; k++)
    {
      if (input < adc_key_val[k])
{
            return k;
        }
   }
  
    if (k >= NUM_KEYS)k = -1;  // No valid key pressed
    return k;
}