added ability to specific hardware endianness

While column 0 is meant to indicate the left most column, the hardware layout of the matrix might not
make the left most column the MSB in the shift register chain. This might happen if you make a mistake in your
hardware (oops). By setting the column endian value of the matrix,the high level software can still reference
column 0 to mean the left most column, and the bit layout sent the shift registers will be adjusted according
to where column 0 physically is in the hardware.

Author: michaelkamprath

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+
+## [Unreleased]
+
+### Changed
+
+### Added
+- Basic capability to specify the endian-ness of the column layout for a matrix. While column 0 is meant to indicate the left most column, the hardware layout of the matrix might not make the left most column the MSB in the shift register chain. This might happen if you make a mistake in your hardware (oops!). By setting the column endian value of the matrix,the high level software can still reference column 0 to mean the left most column, and the bit layout sent the shift registers will be adjusted according to where column 0 physically is in the hardware.
+
 ## [1.1.0] - 2018-02-09
 
 ### Changed

src/BaseLEDMatrix.cpp

@@ -32,13 +32,15 @@ BaseLEDMatrix::BaseLEDMatrix(
 	bool rowControlBitOn,
 	unsigned int interFrameOffTimeMicros,
 	int slavePin,
+	DeviceBitEndian bitEndian,
 	unsigned long maxSPISpeed
 ) :		TimerAction(UPDATE_INTERVAL),
 		_rows(rows),
 		_columns(columns),
 		_columnBitWidth(columnBitWidth),
 		_pwmCycleScanCount(pwmCycleScanCount),
 		_interFrameOffTimeMicros(interFrameOffTimeMicros),
+		_bitEndian(bitEndian),
 		_columnControlBitOn(columnControlBitOn),
 		_rowControlBitOn(rowControlBitOn),
 		_curScreenBitFrames(NULL),
@@ -220,7 +222,7 @@ void BaseLEDMatrix::stopScanning(void) {
 
 unsigned int BaseLEDMatrix::nextRowScanTimerInterval(void) const {
 	// Calculates the microseconds for each scan	
-	return  5*this->baseIntervalMultiplier( _scanPass );
+	return  100*this->baseIntervalMultiplier( _scanPass );
 }
 
 #pragma mark ESP8266 Handlers

src/BaseLEDMatrix.h

@@ -30,6 +30,17 @@
 #endif
 
 class BaseLEDMatrix : public TimerAction {
+public:
+
+	typedef enum {
+		// the left most column in the hardware and MSB in the shift register chain is column 0
+		LED_BIG_ENDIAN,
+		
+		// The columns are laid out in 8 column "bytes" with column 0 being the left most 
+		// bit in the right most byte. Column 8 would be the left most bit in the second 
+		// to the right byte.
+		LED_LITTLE_ENDIAN_8
+	} DeviceBitEndian;
 
 private:
 	unsigned int _rows;
@@ -38,6 +49,7 @@ class BaseLEDMatrix : public TimerAction {
 	unsigned int _pwmCycleScanCount;
 	unsigned int _interFrameOffTimeMicros;
 	unsigned int _interFrameOffTimeInterval;
+	DeviceBitEndian _bitEndian;
 
 	bool _columnControlBitOn;
 	bool _rowControlBitOn;
@@ -106,6 +118,7 @@ class BaseLEDMatrix : public TimerAction {
 			int slavePin = 10	
 #endif
 			,
+			DeviceBitEndian bitEndian = LED_BIG_ENDIAN,
 			unsigned long maxSPISpeed = 18000000
 		);
 	virtual ~BaseLEDMatrix();
@@ -160,6 +173,8 @@ class BaseLEDMatrix : public TimerAction {
 	 */
 	void stopScanning(void);
 
+	DeviceBitEndian bitEndian(void) const			{ return _bitEndian; }
+
 	/**
 	 * This methods are "private" to this class but have to be declared public so 
 	 * the timer interrupt can access them.

src/RGBLEDMatrix.cpp

@@ -36,7 +36,8 @@ RGBLEDMatrix::RGBLEDMatrix(
 	bool columnControlBitOn,
 	bool rowControlBitOn,
 	unsigned int interFrameOffTimeMicros,
-	int slavePin		
+	int slavePin,
+	DeviceBitEndian bitEndian	
 ) :		BaseLEDMatrix(
 				rows,
 				columns,
@@ -45,7 +46,8 @@ RGBLEDMatrix::RGBLEDMatrix(
 				columnControlBitOn,
 				rowControlBitOn,
 				interFrameOffTimeMicros,
-				slavePin
+				slavePin,
+				bitEndian
 			),
 		_bitLayout(bitLayout),
 		_screen_data(NULL)
@@ -216,8 +218,22 @@ void RGBLEDMatrix::setRowBitsForFrame(
 			columnBitIdxIncrement = 1;
 		}
 		for (unsigned int col = 0; col < this->columns(); col++) {
-			RGBColorType rgbValue = image.pixel(row, col);
+			unsigned int endianCol = col;
+			
+			if (this->bitEndian() == LED_LITTLE_ENDIAN_8 ) {
+				// first get the column "byte"
+				unsigned int colByte = col/8;
 
+				// now column's "but" in the byte
+				unsigned int colBit = col%8;
+				
+				// calculate new column location by on "byte"
+				
+				endianCol = this->columns() - (colByte+1)*8 + colBit;
+			}
+			
+		
+			RGBColorType rgbValue = image.pixel(row, endianCol);
 			// a form of Binary Code Modulation is used to control
 			// the LED intensity at variou levels.
 

src/RGBLEDMatrix.h

@@ -93,6 +93,8 @@ class RGBLEDMatrix : public BaseLEDMatrix {
 #else
 			int slavePin = 10	
 #endif
+			,
+			DeviceBitEndian bitEndian = LED_BIG_ENDIAN
 		);
 	virtual ~RGBLEDMatrix();