Convert RGB drawing buffer to WS2812 frame buffer

WS2812Serial.cpp

@@ -22,17 +22,7 @@ void WS2812Serial::begin()
 	UART0_C3 = UART_C3_TXINV;
 	UART0_C5 = UART_C5_TDMAS;
 
-	frameBuffer[0] = 0xDB;
-	frameBuffer[1] = 0xDA;
-	frameBuffer[2] = 0xDB;
-
-	dma->sourceBuffer(frameBuffer, 3);
-	dma->destination(UART0_D);
-	dma->transferSize(1);
-	dma->transferCount(3);
-	dma->disableOnCompletion();
-
-	dma->triggerAtHardwareEvent(DMAMUX_SOURCE_UART0_TX);
+	memset(drawBuffer, 0, numled * 3);
 }
 
 void WS2812Serial::show()
@@ -42,9 +32,42 @@ void WS2812Serial::show()
 	//UART0_D = 0xDA;
 	//UART0_D = 0xDB;
 	
+	const uint8_t *p = drawBuffer;
+	const uint8_t *end = p + (numled * 3);
+	uint8_t *fb = frameBuffer;
+	while (p < end) {
+		uint8_t b = *p++;
+		uint8_t g = *p++;
+		uint8_t r = *p++;
+		uint32_t n=0;
+		switch (config) {
+		  case WS2812_RGB: n = (r << 16) | (g << 8) | b; break;
+		  case WS2812_RBG: n = (r << 16) | (b << 8) | g; break;
+		  case WS2812_GRB: n = (g << 16) | (r << 8) | b; break;
+		  case WS2812_GBR: n = (g << 16) | (b << 8) | r; break;
+		  case WS2812_BRG: n = (b << 16) | (r << 8) | g; break;
+		  case WS2812_BGR: n = (b << 16) | (g << 8) | r; break;
+		}
+		//Serial.printf("n = %06X\n", n);
+		const uint8_t *stop = fb + 8;
+		do {
+			uint8_t x = 0x92;
+			if (!(n & 0x00800000)) x |= 0x01;
+			if (!(n & 0x00400000)) x |= 0x04;
+			if (!(n & 0x00200000)) x |= 0x20;
+			n <<= 3;
+			*fb++ = x;
+		} while (fb < stop);
+	}
+
+	dma->sourceBuffer(frameBuffer, numled * 8);
+	dma->destination(UART0_D);
+	dma->transferSize(1);
+	dma->transferCount(numled * 8);
+	dma->disableOnCompletion();
+	dma->triggerAtHardwareEvent(DMAMUX_SOURCE_UART0_TX);
 	dma->enable();
 	UART0_C2 = UART_C2_TE | UART_C2_TIE;
-
 }
 
 

WS2812Serial.h

@@ -23,16 +23,16 @@ public:
 	void setPixel(uint32_t num, int color) {
 		if (num >= numled) return;
 		num *= 3;
-		frameBuffer[num+0] = color;
-		frameBuffer[num+1] = color >> 8;
-		frameBuffer[num+2] = color >> 16;
+		drawBuffer[num+0] = color & 255;
+		drawBuffer[num+1] = (color >> 8) & 255;
+		drawBuffer[num+2] = (color >> 16) & 255;
 	}
 	void setPixel(uint32_t num, uint8_t red, uint8_t green, uint8_t blue) {
 		if (num >= numled) return;
 		num *= 3;
-		frameBuffer[num+0] = blue;
-		frameBuffer[num+1] = green;
-		frameBuffer[num+2] = red;
+		drawBuffer[num+0] = blue;
+		drawBuffer[num+1] = green;
+		drawBuffer[num+2] = red;
 	}
 	void show();
 	bool busy();
@@ -44,10 +44,8 @@ private:
 	const uint8_t config;
 	uint8_t *frameBuffer;
 	uint8_t *drawBuffer;
-	//HardwareSerial &serial;
 	KINETISK_UART_t *uart;
 	DMAChannel *dma = nullptr;
-
 };
 
 #endif