Basic support for pcf8574 i2c keypad

Author: Vladimir Kozlov

src/menuIO/I2CkeypadIn.h

@@ -0,0 +1,43 @@
+/* -*- C++ -*- */
+/**************
+Jan. 2018 Rui Azevedo - ruihfazevedo(@rrob@)gmail.com
+
+I2C keypad driver
+using
+   https://github.com/whatnick/i2ckeypad
+
+   Note: you may be need to adjust keypad-to-pcf8574 pin mappings and keymap in i2ckeypad.cpp for your specific keypad.
+
+***/
+
+#ifndef RSITE_I2CKEYPAD_DEF_H
+  #define RSITE_I2CKEYPAD_DEF_H
+  #include "../menuDefs.h"
+
+  #include <i2ckeypad.h>
+  namespace Menu {
+
+    class I2CkeypadIn:public menuIn {
+    public:
+      char key=0;
+      i2ckeypad * in;
+      I2CkeypadIn(i2ckeypad * in):in(in) {}
+      int available(void) {
+		  return peek()!=0;
+	  }
+      int peek(void) { 
+		  return key != 0 ? key : (key=in->get_key()) ?key : 0;
+	  }
+      int read() {
+        if (key != 0) {
+          char k=key;
+          key=0;
+          return k;
+        }
+        return available()?read():0;
+      }
+      void flush() {}
+      size_t write(uint8_t v) {return 0;}
+    };
+  };
+#endif