Index of sample code pages - Revision history

69.77.190.198: /* Using #define for Magic Numbers */

2011-12-18T20:06:46Z

Using #define for Magic Numbers

2011-12-18T20:05:25Z

Using #define to Support Multiple CPU Targets

2010-01-02T06:06:54Z

The perfect second

2009-07-14T05:45:02Z

unsignedc char

2009-05-20T02:13:16Z

Using #define to Support Multiple CPU Targets

2009-05-20T01:31:50Z

Using #define to Configure Hardware

2009-05-20T01:25:31Z

Using #define to Support Multiple CPU Targets

2009-05-20T01:24:37Z

Using #define to Support Multiple CPU Targets

2009-05-20T01:19:12Z

Using #define for Magic Numbers

2009-04-16T01:27:28Z

Using #define for Magic Numbers

@@ Line 242: / Line 242: @@
       if ( a == MAX_8BIT ) ....
-might be more meaningfull.  ( note this is not a great example, best I could come up with right now )  You could consider that port addresses are aqctually numbers ( and different for diffent processors ) and that symbols like PORTB are actually magic numbers defined differently for different processors.
+might be more meaningful.  ( note this is not a great example, best I could come up with right now )  You could consider that port addresses are actually numbers ( and different for different processors ) and that symbols like PORTB are actually magic numbers defined differently for different processors.
 == Counting Down with Unsigned Numbers ==

← Older revision		Revision as of 20:05, 18 December 2011
Line 222:		Line 222:
	#endif		#endif

−	it will only compile if the target is a 16f877A. This way one file can contain code for a bunch od different processors.	+	it will only compile if the target is a 16f877A. This way one file can contain code for a bunch of different processors.

← Older revision		Revision as of 06:06, 2 January 2010
Line 17:		Line 17:
	Timing routines, showing how seconds can be counted. Want high accuracy even with odd clock rates.		Timing routines, showing how seconds can be counted. Want high accuracy even with odd clock rates.

		+	This dudes routines will absolutely blow your sox off. Really.
		+	http://www.romanblack.com/one_sec.htm

	== Using I2C Memory ==		== Using I2C Memory ==

@@ Line 52: / Line 52: @@
 == Software Circular Buffer ==
-A place to store and retrieve data, say bytes.  First in First out.  Methods to add and remove data.    ''' Code still needed.'''
+A place to store and retrieve data, say bytes.  First in First out.  Methods to add and remove data.
 == [[read before write]] ==

← Older revision		Revision as of 02:13, 20 May 2009
Line 93:		Line 93:

	it will only compile if the target is a 16f877A. This way one file can contain code for a bunch od different processors.		it will only compile if the target is a 16f877A. This way one file can contain code for a bunch od different processors.
		+
		+
		+	If you want to include more than one processor you can use code like:
		+
		+
		+	#if ( defined ( _PIC16F877A_H_ ) \|\| defined ( _PIC16F877_H_ ) )
		+	TRISA = 0b00011111;
		+	#endif

	== Using #define for Magic Numbers ==		== Using #define for Magic Numbers ==

← Older revision		Revision as of 01:31, 20 May 2009
Line 65:		Line 65:


		+	Suppose you are lighting an LED on PORTB.3. If you use the following defines:
		+
		+	#define LED_PORT PORTB
		+	#define LED_BIT 3
		+
		+	then
		+
		+	set_bit( LED_PORT, LED_BIT );
		+
		+	can be used instead of
		+
		+	set_bit( PORTB, 3 );
		+
		+	There are a couple of advantages to this:
		+
		+	* The code is easier to read and write.
		+	* Reconfiguring the hardware can be done simply by just changing the #defines.
		+	* Reading the #defines ( normally all at the top of the program ) often gives a good overview of the hardware assignment.

	== Using #define to Support Multiple CPU Targets ==		== Using #define to Support Multiple CPU Targets ==

@@ Line 71: / Line 71: @@
       #ifdef  _PIC16F877A_H_
-	TRISA = 0b00011111;
+          TRISA = 0b00011111;
       #endif

← Older revision		Revision as of 01:24, 20 May 2009
Line 68:		Line 68:
	== Using #define to Support Multiple CPU Targets ==		== Using #define to Support Multiple CPU Targets ==

		+	The compiler ( actually I think the preprocessor ) always defines a symbol that contains the name of the target processor, for example _PIC16F877A_H_. This means you can surround code with the following preprocessor commands:
		+
		+	#ifdef _PIC16F877A_H_
		+	TRISA = 0b00011111;
		+	#endif
		+
		+	it will only compile if the target is a 16f877A. This way one file can contain code for a bunch od different processors.

	== Using #define for Magic Numbers ==		== Using #define for Magic Numbers ==

← Older revision		Revision as of 01:27, 16 April 2009
Line 70:		Line 70:

	== Using #define for Magic Numbers ==		== Using #define for Magic Numbers ==
		+
		+	A magic number is a number, that for some reason, has a special meaning. For example the maximum number for an 8 bit number is 255, but a reader of the program might not recognize this significance. If you:
		+
		+	#define MAX_8BIT = 255
		+
		+	then a test like
		+
		+	if ( a == MAX_8BIT ) ....
		+
		+	might be more meaningfull. ( note this is not a great example, best I could come up with right now )

	== Counting Down with Unsigned Numbers ==		== Counting Down with Unsigned Numbers ==