Constructor using pin number rather than port name

WS2812Serial.cpp

@@ -1,37 +1,45 @@
 
 #include "WS2812Serial.h"
 
-void WS2812Serial::begin()
+bool WS2812Serial::begin()
 {
-	if (!uart) return;
-	if (!dma) dma = new DMAChannel;
-	if (!dma) return;
-
-	SIM_SCGC4 |= SIM_SCGC4_UART0;
-	uint32_t divisor = BAUD2DIV(2400000);
-
-	CORE_PIN1_CONFIG = PORT_PCR_DSE | PORT_PCR_SRE | PORT_PCR_MUX(3);
-
-        UART0_BDH = (divisor >> 13) & 0x1F;
-        UART0_BDL = (divisor >> 5) & 0xFF;
-        UART0_C4 = divisor & 0x1F;
-
-	UART0_C1 = 0;
-	UART0_PFIFO = 0;
-	UART0_C2 = UART_C2_TE;
-	UART0_C3 = UART_C3_TXINV;
-	UART0_C5 = UART_C5_TDMAS;
+	uint32_t divisor, portconfig, hwtrigger;
+	KINETISK_UART_t *uart;
 
+	switch (pin) {
+	  case 1:
+		uart = &KINETISK_UART0;
+		divisor = BAUD2DIV(2400000);
+		portconfig = PORT_PCR_DSE | PORT_PCR_SRE | PORT_PCR_MUX(3);
+		hwtrigger = DMAMUX_SOURCE_UART0_TX;
+		SIM_SCGC4 |= SIM_SCGC4_UART0;
+		break;
+	  default:
+		return false; // pin not supported
+	}
+	if (!dma) {
+		dma = new DMAChannel;
+		if (!dma) return false; // unable to allocate DMA channel
+	}
+	uart->BDH = (divisor >> 13) & 0x1F;
+	uart->BDL = (divisor >> 5) & 0xFF;
+	uart->C4 = divisor & 0x1F;
+	uart->C1 = 0;
+	uart->PFIFO = 0;
+	uart->C2 = UART_C2_TE | UART_C2_TIE;
+	uart->C3 = UART_C3_TXINV;
+	uart->C5 = UART_C5_TDMAS;
+	*(portConfigRegister(pin)) = portconfig;
+	dma->destination(uart->D);
+	dma->triggerAtHardwareEvent(hwtrigger);
 	memset(drawBuffer, 0, numled * 3);
+	return true;
 }
 
 void WS2812Serial::show()
 {
-
-	//UART0_D = 0xDB;
-	//UART0_D = 0xDA;
-	//UART0_D = 0xDB;
-	
+	// TODO: wait if prior DMA in progress
+	// TODO: wait 300us WS2812 reset time
 	const uint8_t *p = drawBuffer;
 	const uint8_t *end = p + (numled * 3);
 	uint8_t *fb = frameBuffer;
@@ -48,7 +56,6 @@ void WS2812Serial::show()
 		  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;
@@ -59,15 +66,10 @@ void WS2812Serial::show()
 			*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

@@ -13,13 +13,11 @@
 
 class WS2812Serial {
 public:
-	constexpr WS2812Serial(uint16_t n, void *f, void *d, HardwareSerial &s, uint8_t c) :
-		numled(n), config(c),
-		frameBuffer((uint8_t *)f), drawBuffer((uint8_t *)d),
-		uart( &s == &Serial1 ? &KINETISK_UART0 : nullptr)
-	{
+	constexpr WS2812Serial(uint16_t num, void *fb, void *db, uint8_t pin, uint8_t cfg) :
+		numled(num), pin(pin), config(cfg),
+		frameBuffer((uint8_t *)fb), drawBuffer((uint8_t *)db) {
 	}
-	void begin();
+	bool begin();
 	void setPixel(uint32_t num, int color) {
 		if (num >= numled) return;
 		num *= 3;
@@ -41,10 +39,10 @@ public:
 	}
 private:
 	const uint16_t numled;
+	const uint8_t pin;
 	const uint8_t config;
 	uint8_t *frameBuffer;
 	uint8_t *drawBuffer;
-	KINETISK_UART_t *uart;
 	DMAChannel *dma = nullptr;
 };