add example

libraries/I2CKeyPad/examples/I2Ckeypad_long_press/I2Ckeypad_long_press.ino

@@ -0,0 +1,145 @@
+//
+//    FILE: I2Ckeypad_long_press.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: demo
+//     URL: https://github.com/RobTillaart/I2CKeyPad
+//          https://github.com/RobTillaart/I2CKeyPad/issues/17
+//
+//  PCF8574
+//    pin p0-p3 rows
+//    pin p4-p7 columns
+//  4x4 or smaller keypad.
+
+
+#include "Wire.h"
+#include "I2CKeyPad.h"
+
+const uint8_t KEYPAD_ADDRESS = 0x38;
+I2CKeyPad keyPad(KEYPAD_ADDRESS);
+
+uint32_t lastKeyChecked = 0;
+uint32_t startKey = 0;
+uint32_t interval = 100;  //  milliseconds.
+//  keep previous key value to detect long keypresses.
+uint8_t  prevKey = I2C_KEYPAD_NOKEY;
+
+
+#define  SHORT_THRESHOLD     300
+#define  MEDIUM_THRESHOLD    600
+#define  LONG_THRESHOLD      1200
+
+
+enum STATE
+{
+  PRESS        = 1,
+  SHORT_PRESS,
+  MEDIUM_PRESS,
+  LONG_PRESS,
+  RELEASE,
+  NOKEY,
+};
+STATE state = NOKEY;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.println("I2C_KEYPAD_LIB_VERSION: ");
+  Serial.println(I2C_KEYPAD_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+  Wire.setClock(400000);
+  if (keyPad.begin() == false)
+  {
+    Serial.println("\nERROR: cannot communicate to keypad.\nPlease reboot.\n");
+    while (1);
+  }
+}
+
+
+void loop()
+{
+  uint32_t now = millis();
+  char keys[] = "123A456B789C*0#DNF";  //  N = NoKey, F = Fail
+
+  //  read the keypad every interval.
+  if (now - lastKeyChecked >= interval)
+  {
+    lastKeyChecked = now;
+    //  read the keypad
+    uint8_t key = keyPad.getKey();
+    switch (key)
+    {
+      case I2C_KEYPAD_FAIL: state = NOKEY;
+        break;
+
+      case I2C_KEYPAD_NOKEY:
+        if (key == prevKey)
+        {
+          state = NOKEY;
+        }
+        else
+        {
+          //  note handles press at release time!
+          handlePress(state);
+          state = RELEASE;
+        }
+        break;
+
+      default:
+        if (key == prevKey)
+        {
+          if (now - startKey < SHORT_THRESHOLD)
+          {
+            state = SHORT_PRESS;
+          }
+          else if (now - startKey < MEDIUM_THRESHOLD)
+          {
+            state = MEDIUM_PRESS;
+          }
+          else
+          {
+            state = LONG_PRESS;
+          }
+        }
+        else
+        {
+          state = PRESS;
+          startKey = now;
+        }
+        break;
+    }
+    Serial.print("STATE:\t ");
+    Serial.print(state);
+    Serial.print("\t");
+    Serial.println(keys[key]);
+    prevKey = key;
+  }
+}
+
+
+void handlePress(STATE state)
+{
+  switch (state)
+  {
+    case PRESS:
+      //  handle very short press.
+      break;
+    case SHORT_PRESS:
+      //  handle short press.
+      break;
+    case MEDIUM_PRESS:
+      //  handle medium press.
+      break;
+    case LONG_PRESS:
+      //  handle short press.
+      break;
+    default:
+      //  do nothing
+      break;
+  }
+}
+
+//  -- END OF FILE --