Add enumeration with pin values for digitalWrite etc (#28)

* Add enumeration with pin values for digitalWrite etc

* It is recommended not to use enum class if implicit cast to value is required. C++23 is said to provide a standard library helper, until then, for scoping, wrapping in a struct is recommended.

Co-authored-by: Bertrand Lemasle <[email protected]>

Author: dok-net

src/MCP23017.h

@@ -12,6 +12,28 @@ enum class MCP23017Port : uint8_t
 	B = 1
 };
 
+struct MCP23017Pin
+{
+	enum Names {
+		GPA0 = 0,
+		GPA1,
+		GPA2,
+		GPA3,
+		GPA4,
+		GPA5,
+		GPA6,
+		GPA7,
+		GPB0 = 8,
+		GPB1,
+		GPB2,
+		GPB3,
+		GPB4,
+		GPB5,
+		GPB6,
+		GPB7
+	};
+};
+
 /**
  * Controls if the two interrupt pins mirror each other.
  * See "3.6 Interrupt Logic".