commit again

README.md

@@ -3,6 +3,9 @@ Arduino library for faster `digitalWrite()` using direct port manipulation and m
 Which actually also does faster `pinMode()` and `digitalRead()`.
 
 ## Usage
+Include the library:
+`#include <digitalWriteFast.h>`
+
 Macro definitions:
 * `digitalWriteFast(pinNum, state)` (sets or clears pin/port faster) 
 * `pinModeFast(pinNum, mode)` (sets pin/port as input or output faster)
@@ -19,9 +22,12 @@ For example:
 * use '#define pinNum 10' instead of `int pinNum = 10;`
 * use 'const int pinNum 10' instead of `int pinNum = 10;`
 
-Setting the parameter as a variable would cause the macro to revert back to the traditional `digitalWrite`, `pinMode` or `digitalRead` and operates more slowly. 
+Setting the parameter as a variable would cause the macro to return an error during compilation.
+
+This makes sure `digitalWriteFast` that produces faster toggling, and notifies the programmer the specific area where toggling is slow. Otherwise, use normal `digitalWrite`
+
+This is opposed to the forked library form Watterott, where if a variable is used as the parameter, the macro would revert to use sold `digitalWrite`, and remain undetected.
 
-No error or warning will be thrown, but function works properly, without direct port manipualtion (slow). 
 
 ## Speed
 
@@ -44,6 +50,11 @@ This library makes it easier by using `digitalWriteFast()` and the macro will re
 
 If not in the list, the macro will revert back to  `digitalWrite()`, `pinMode()` or `digitalRead()`
 
+## Installation
+1. Download the repo as zip, extract and place into Arduino IDE libraries folder.
+2. Rename "digitalWriteFast-master" to "digitalWriteFast" Arduino IDE does not accept dash character.
+
+
 ## Reference
 Fork of Watterott's https://github.com/watterott/Arduino-Libs/tree/master/digitalWriteFast
 I just forked the whole repo, and delete unrelated files, I tried sparse checkout and gave up.

digitalWriteFast.h

@@ -301,20 +301,22 @@
 //#endif  //#ifndef digitalPinToPortReg
 
 
+//ref: http://forum.arduino.cc/index.php?topic=140409.msg1054868#msg1054868
+//void OutputsErrorIfCalled( void ) __attribute__ (( error( "Line: "__line__ "Variable used for digitalWriteFast") ));
+void NonConstantUsed( void ) __attribute__ (( error("") ));
+
 
 #ifndef digitalWriteFast
 #if (defined(__AVR__) || defined(ARDUINO_ARCH_AVR))
-#define digitalWriteSlow(P, V) \
- digitalWrite((P), (V)); \
- OutputsErrorIfCalled(); 
 #define digitalWriteFast(P, V) \
 if (__builtin_constant_p(P) && __builtin_constant_p(V)) { \
   BIT_WRITE(*__digitalPinToPortReg(P), __digitalPinToBit(P), (V)); \
 } else { \
-  digitalWrite((P), (V)); \
+  NonConstantUsed(); \
 }
 #else
-#define digitalWriteFast digitalWrite
+//#define digitalWriteFast digitalWrite
+#error Non-AVR device, unsupported.
 #endif
 #endif
 
@@ -325,10 +327,11 @@ if (__builtin_constant_p(P) && __builtin_constant_p(V)) { \
 if (__builtin_constant_p(P) && __builtin_constant_p(V)) { \
   BIT_WRITE(*__digitalPinToDDRReg(P), __digitalPinToBit(P), (V)); \
 } else { \
-  pinMode((P), (V)); \
+  NonConstantUsed(); \
 }
 #else
-#define pinModeFast pinMode
+//#define pinModeFast pinMode
+#error Non-AVR device, unsupported.
 #endif
 #endif
 
@@ -337,11 +340,14 @@ if (__builtin_constant_p(P) && __builtin_constant_p(V)) { \
 #if (defined(__AVR__) || defined(ARDUINO_ARCH_AVR))
 #define digitalReadFast(P) ( (int) __digitalReadFast((P)) )
 #define __digitalReadFast(P ) \
-  (__builtin_constant_p(P) ) ? ( \
-  ( BIT_READ(*__digitalPinToPINReg(P), __digitalPinToBit(P))) ) : \
-  digitalRead((P))
+if (__builtin_constant_p(P)) { \
+  BIT_READ(*__digitalPinToPINReg(P), __digitalPinToBit(P))); \
+} else { \
+  NonConstantUsed(); \
+}
 #else
-#define digitalReadFast digitalRead
+//#define digitalReadFast digitalRead
+#error Non-AVR device, unsupported.
 #endif
 #endif