Revision 0:a8535703f23b, committed 2014-01-04

Comitter:

bikeNomad

Date:

Sat Jan 04 00:40:08 2014 +0000

Child:

1:39db2057b5da

Commit message:

Initial revision of library.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Colors.cpp	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,90 @@
+#include <math.h>
+#include <mbed.h>
+#include "Colors.h"
+
+void HSBtoRGB(float hue, float saturation, float brightness, uint8_t *pr, uint8_t *pg, uint8_t *pb)
+{
+    uint8_t r = 0, g = 0, b = 0;
+    if (saturation == 0) {
+        r = g = b = (uint8_t) (brightness * 255.0f + 0.5f);
+    } else {
+        float h = (hue - (float)floor(hue)) * 6.0f;
+        float f = h - (float)floor(h);
+        float p = brightness * (1.0f - saturation);
+        float q = brightness * (1.0f - saturation * f);
+        float t = brightness * (1.0f - (saturation * (1.0f - f)));
+        switch ((int) h) {
+            case 0:
+                r = (int) (brightness * 255.0f + 0.5f);
+                g = (int) (t * 255.0f + 0.5f);
+                b = (int) (p * 255.0f + 0.5f);
+                break;
+            case 1:
+                r = (int) (q * 255.0f + 0.5f);
+                g = (int) (brightness * 255.0f + 0.5f);
+                b = (int) (p * 255.0f + 0.5f);
+                break;
+            case 2:
+                r = (int) (p * 255.0f + 0.5f);
+                g = (int) (brightness * 255.0f + 0.5f);
+                b = (int) (t * 255.0f + 0.5f);
+                break;
+            case 3:
+                r = (int) (p * 255.0f + 0.5f);
+                g = (int) (q * 255.0f + 0.5f);
+                b = (int) (brightness * 255.0f + 0.5f);
+                break;
+            case 4:
+                r = (int) (t * 255.0f + 0.5f);
+                g = (int) (p * 255.0f + 0.5f);
+                b = (int) (brightness * 255.0f + 0.5f);
+                break;
+            case 5:
+                r = (int) (brightness * 255.0f + 0.5f);
+                g = (int) (p * 255.0f + 0.5f);
+                b = (int) (q * 255.0f + 0.5f);
+                break;
+        }
+    }
+    *pr = r;
+    *pg = g;
+    *pb = b;
+}
+
+float* RGBtoHSB(uint8_t r, uint8_t g, uint8_t b, float* hsbvals)
+{
+    float hue, saturation, brightness;
+    if (!hsbvals) {
+        hsbvals = new float[3];
+    }
+    uint8_t cmax = (r > g) ? r : g;
+    if (b > cmax) cmax = b;
+    uint8_t cmin = (r < g) ? r : g;
+    if (b < cmin) cmin = b;
+
+    brightness = ((float) cmax) / 255.0f;
+    if (cmax != 0)
+        saturation = ((float) (cmax - cmin)) / ((float) cmax);
+    else
+        saturation = 0;
+    if (saturation == 0)
+        hue = 0;
+    else {
+        float redc = ((float) (cmax - r)) / ((float) (cmax - cmin));
+        float greenc = ((float) (cmax - g)) / ((float) (cmax - cmin));
+        float bluec = ((float) (cmax - b)) / ((float) (cmax - cmin));
+        if (r == cmax)
+            hue = bluec - greenc;
+        else if (g == cmax)
+            hue = 2.0f + redc - bluec;
+        else
+            hue = 4.0f + greenc - redc;
+        hue = hue / 6.0f;
+        if (hue < 0)
+            hue = hue + 1.0f;
+    }
+    hsbvals[0] = hue;
+    hsbvals[1] = saturation;
+    hsbvals[2] = brightness;
+    return hsbvals;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Colors.h	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,51 @@
+#include <mbed.h>
+
+#ifndef __included_colors_h
+#define __included_colors_h
+
+/**
+ * Converts the components of a color, as specified by the HSB
+ * model, to an equivalent set of values for the default RGB model.
+ * <p>
+ * The <code>saturation</code> and <code>brightness</code> components
+ * should be floating-point values between zero and one
+ * (numbers in the range 0.0-1.0).  The <code>hue</code> component
+ * can be any floating-point number.  The floor of this number is
+ * subtracted from it to create a fraction between 0 and 1.  This
+ * fractional number is then multiplied by 360 to produce the hue
+ * angle in the HSB color model.
+ * <p>
+ * The integer that is returned by <code>HSBtoRGB</code> encodes the
+ * value of a color in bits 0-23 of an integer value that is the same
+ * format used by the method {@link #getRGB() <code>getRGB</code>}.
+ * This integer can be supplied as an argument to the
+ * <code>Color</code> constructor that takes a single integer argument.
+ * @param     hue   the hue component of the color
+ * @param     saturation   the saturation of the color
+ * @param     brightness   the brightness of the color
+ * @return    the RGB value of the color with the indicated hue,
+ *                            saturation, and brightness.
+ */
+void HSBtoRGB(float hue, float saturation, float brightness, uint8_t *pr, uint8_t *pg, uint8_t *pb);
+
+/**
+ * Converts the components of a color, as specified by the default RGB
+ * model, to an equivalent set of values for hue, saturation, and
+ * brightness that are the three components of the HSB model.
+ * <p>
+ * If the <code>hsbvals</code> argument is <code>null</code>, then a
+ * new array is allocated to return the result. Otherwise, the method
+ * returns the array <code>hsbvals</code>, with the values put into
+ * that array.
+ * @param     r   the red component of the color
+ * @param     g   the green component of the color
+ * @param     b   the blue component of the color
+ * @param     hsbvals  the array used to return the
+ *                     three HSB values, or <code>null</code>
+ * @return    an array of three elements containing the hue, saturation,
+ *                     and brightness (in that order), of the color with
+ *                     the indicated red, green, and blue components.
+ */
+float* RGBtoHSB(uint8_t r, uint8_t g, uint8_t b, float* hsbvals);
+
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LedStrip.cpp	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,80 @@
+#include "LedStrip.h"
+
+LedStrip::LedStrip(int n)
+{
+   // Allocate 3 bytes per pixel:
+    numLEDs = n;
+    pixels = (uint8_t *)malloc(numPixelBytes());
+    if (pixels) {
+        memset(pixels, 0x00, numPixelBytes()); // Init to RGB 'off' state
+    }
+}
+
+LedStrip::~LedStrip()
+{
+    free(pixels);
+}
+ 
+uint32_t LedStrip::total_luminance(void)
+{
+    uint32_t running_total;
+    running_total = 0;
+    for (int i=0; i< numPixelBytes(); i++)
+        running_total += pixels[i];
+    return running_total;
+}
+
+// Convert R,G,B to combined 32-bit color
+uint32_t LedStrip::Color(uint8_t r, uint8_t g, uint8_t b)
+{
+    // Take the lowest 7 bits of each value and append them end to end
+    // We have the top bit set high (its a 'parity-like' bit in the protocol
+    // and must be set!)
+    return ((uint32_t)g << 16) | ((uint32_t)r << 8) | (uint32_t)b;
+}
+
+// store the rgb component in our array
+void LedStrip::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
+{
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3  ] = g;
+    pixels[n*3+1] = r;
+    pixels[n*3+2] = b;
+}
+
+void LedStrip::setPixelR(uint16_t n, uint8_t r)
+{
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3+1] = r;
+}
+
+void LedStrip::setPixelG(uint16_t n, uint8_t g)
+{
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3] = g;
+}
+
+void LedStrip::setPixelB(uint16_t n, uint8_t b)
+{
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3+2] = b;
+}
+
+void LedStrip::setPackedPixels(uint8_t * buffer, uint32_t n)
+{
+    if (n >= numLEDs) return;
+    memcpy(pixels, buffer, (size_t) (n*3));
+}
+
+void LedStrip::setPixelColor(uint16_t n, uint32_t c)
+{
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3  ] = (c >> 16);
+    pixels[n*3+1] = (c >>  8);
+    pixels[n*3+2] =  c;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LedStrip.h	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,44 @@
+// Parent class for all addressable LED strips.
+// Partially based on work by and (c) 2011 Jelmer Tiete
+// whose library is ported from the Arduino implementation of Adafruit Industries
+// found at: http://github.com/adafruit/LPD8806
+// and their strips: http://www.adafruit.com/products/306
+// Released under the MIT License: http://mbed.org/license/mit
+
+// This is a pure virtual parent class for all LED strips, so that different types
+// of strip may be used in a single array or container.
+
+#include "mbed.h"
+
+#ifndef LEDSTRIP_H
+#define LEDSTRIP_H
+
+class LedStrip
+{
+public:
+    LedStrip(int n);
+    ~LedStrip();
+
+    virtual void begin(void)=0;
+    virtual void show(void)=0;
+    virtual void blank(void)=0;
+
+    static uint32_t Color(uint8_t r, uint8_t g, uint8_t b);
+
+    uint16_t numPixels(void) { return numLEDs; }
+    uint16_t numPixelBytes(void) { return numLEDs * 3; }
+    uint32_t total_luminance(void);
+
+    void setPixelB(uint16_t n, uint8_t b);
+    void setPixelG(uint16_t n, uint8_t g);
+    void setPixelR(uint16_t n, uint8_t r);
+    
+    void setPixelColor(uint16_t n, uint32_t c);
+    void setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b);
+    void setPackedPixels(uint8_t * buffer, uint32_t n);
+
+protected:
+    uint8_t *pixels;     // Holds LED color values
+    uint16_t numLEDs;     // Number of RGB LEDs in strand
+};
+#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2811.cpp	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,399 @@
+// 800 KHz WS2811 driver driving potentially many LED strings.
+// Uses 3-phase DMA
+// 16K SRAM less stack, etc.
+//
+// Per LED: 3 bytes (malloc'd) for RGB data
+//
+// Per LED strip / per LED
+//          96 bytes (static) for bit data
+//        + 96 bytes (static) for ones data
+//        = 192 bytes
+//
+//        40 LEDs max per string = 7680 bytes static
+//
+//        40 LEDs: 7680 + 40*3 = 7800 bytes
+//        80 LEDs: 7680 + 80*3 = 7920 bytes
+
+#include "MKL25Z4.h"
+#include "LedStrip.h"
+#include "WS2811.h"
+
+//
+// Configuration
+//
+
+// Define MONITOR_TPM0_PWM as non-zero to monitor PWM timing on PTD0 and PTD1
+// PTD0 TPM0/CH0 PWM_1 J2/06
+// PTD1 TPM0/CH1 PWM_2 J2/12 (also LED_BLUE)
+#define MONITOR_TPM0_PWM 0
+
+// define DEBUG_PIN to identify a pin in PORTD used for debug output
+// #define DEBUG_PIN 4 /* PTD4 debugOut */
+
+#ifdef DEBUG_PIN
+#define DEBUG 1
+#endif
+
+#if DEBUG
+#define DEBUG_MASK (1<<DEBUG_PIN)
+#define RESET_DEBUG (IO_GPIO->PDOR &= ~DEBUG_MASK)
+#define SET_DEBUG (IO_GPIO->PDOR |= DEBUG_MASK)
+#else
+#define DEBUG_MASK 0
+#define RESET_DEBUG (void)0
+#define SET_DEBUG (void)0
+#endif
+
+static PORT_Type volatile * const IO_PORT = PORTD;
+static GPIO_Type volatile * const IO_GPIO = PTD;
+
+// 48 MHz clock, no prescaling.
+#define NSEC_TO_TICKS(nsec) ((nsec)*48/1000)
+#define USEC_TO_TICKS(usec) ((usec)*48)
+static const uint32_t CLK_NSEC = 1250;
+static const uint32_t tpm_period    = NSEC_TO_TICKS(CLK_NSEC);
+static const uint32_t tpm_p0_period = NSEC_TO_TICKS(250);
+static const uint32_t tpm_p1_period = NSEC_TO_TICKS(650);
+static const uint32_t guardtime_period = USEC_TO_TICKS(55);   // guardtime minimum 50 usec.
+
+enum DMA_MUX_SRC {
+    DMA_MUX_SRC_TPM0_CH_0     = 24,
+    DMA_MUX_SRC_TPM0_CH_1,
+    DMA_MUX_SRC_TPM0_Overflow = 54,
+};
+
+enum DMA_CHAN {
+    DMA_CHAN_START = 0,
+    DMA_CHAN_0_LOW = 1,
+    DMA_CHAN_1_LOW = 2,
+    N_DMA_CHANNELS
+};
+
+volatile bool WS2811::dma_done = true;
+
+// class static
+bool WS2811::initialized = false;
+
+// class static
+uint32_t WS2811::enabledPins = 0;
+
+#define WORD_ALIGNED __attribute__ ((aligned(4)))
+
+#define DMA_LEADING_ZEROS  2
+#define BITS_PER_RGB       24
+#define DMA_TRAILING_ZEROS 1
+
+static struct {
+    uint32_t start_t1_low[ DMA_LEADING_ZEROS ];
+    uint32_t dmaWords[ BITS_PER_RGB * MAX_LEDS_PER_STRIP ];
+    uint32_t trailing_zeros_1[ DMA_TRAILING_ZEROS ];
+
+    uint32_t start_t0_high[ DMA_LEADING_ZEROS - 1 ];
+    uint32_t allOnes[ BITS_PER_RGB * MAX_LEDS_PER_STRIP ];
+    uint32_t trailing_zeros_2[ DMA_TRAILING_ZEROS + 1 ];
+} dmaData WORD_ALIGNED;
+
+// class static
+void WS2811::hw_init()
+{
+    if (initialized) return;
+
+    dma_data_init();
+    clock_init();
+    dma_init();
+    io_init();
+    tpm_init();
+
+    initialized = true;
+
+    SET_DEBUG;
+    RESET_DEBUG;
+}
+
+// class static
+void WS2811::dma_data_init()
+{
+    memset(dmaData.allOnes, 0xFF, sizeof(dmaData.allOnes));
+
+#if DEBUG
+    for (unsigned i = 0; i < BITS_PER_RGB * MAX_LEDS_PER_STRIP; i++)
+        dmaData.dmaWords[i] = DEBUG_MASK;
+#endif
+}
+
+// class static
+
+/// Enable PORTD, DMA and TPM0 clocking
+void WS2811::clock_init()
+{
+    SIM->SCGC5 |= SIM_SCGC5_PORTD_MASK;
+    SIM->SCGC6 |= SIM_SCGC6_DMAMUX_MASK | SIM_SCGC6_TPM0_MASK; // Enable clock to DMA mux and TPM0
+    SIM->SCGC7 |= SIM_SCGC7_DMA_MASK;  // Enable clock to DMA
+
+    SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: MCGFLLCLK or MCGPLLCLK
+}
+
+// class static
+
+/// Configure GPIO output pins
+void WS2811::io_init()
+{
+    uint32_t m = 1;
+    for (uint32_t i = 0; i < 32; i++) {
+        // set up each pin
+        if (m & enabledPins) {
+            IO_PORT->PCR[i] = PORT_PCR_MUX(1) // GPIO
+                              | PORT_PCR_DSE_MASK; // high drive strength
+        }
+        m <<= 1;
+    }
+
+    IO_GPIO->PDDR |= enabledPins;      // set as outputs
+
+#if MONITOR_TPM0_PWM
+    // PTD0 CH0 monitor: TPM0, high drive strength
+    IO_PORT->PCR[0] = PORT_PCR_MUX(4) | PORT_PCR_DSE_MASK;
+    // PTD1 CH1 monitor: TPM0, high drive strength
+    IO_PORT->PCR[1] = PORT_PCR_MUX(4) | PORT_PCR_DSE_MASK;
+    IO_GPIO->PDDR  |= 3;               // set as outputs
+    IO_GPIO->PDOR &= ~(enabledPins | 3);     // initially low
+#else
+    IO_GPIO->PDOR &= ~enabledPins;     // initially low
+#endif
+
+#if DEBUG
+    IO_PORT->PCR[DEBUG_PIN] = PORT_PCR_MUX(1) | PORT_PCR_DSE_MASK;
+    IO_GPIO->PDDR |= DEBUG_MASK;
+    IO_GPIO->PDOR &= ~DEBUG_MASK;
+#endif
+}
+
+// class static
+
+/// Configure DMA and DMAMUX
+void WS2811::dma_init()
+{
+    // reset DMAMUX
+    DMAMUX0->CHCFG[DMA_CHAN_START] = 0;
+    DMAMUX0->CHCFG[DMA_CHAN_0_LOW] = 0;
+    DMAMUX0->CHCFG[DMA_CHAN_1_LOW] = 0;
+
+    // wire our DMA event sources into the first three DMA channels
+    // t=0: all enabled outputs go high on TPM0 overflow
+    DMAMUX0->CHCFG[DMA_CHAN_START] = DMAMUX_CHCFG_ENBL_MASK | DMAMUX_CHCFG_SOURCE(DMA_MUX_SRC_TPM0_Overflow);
+    // t=tpm_p0_period: all of the 0 bits go low.
+    DMAMUX0->CHCFG[DMA_CHAN_0_LOW] = DMAMUX_CHCFG_ENBL_MASK | DMAMUX_CHCFG_SOURCE(DMA_MUX_SRC_TPM0_CH_0);
+    // t=tpm_p1_period: all outputs go low.
+    DMAMUX0->CHCFG[DMA_CHAN_1_LOW] = DMAMUX_CHCFG_ENBL_MASK | DMAMUX_CHCFG_SOURCE(DMA_MUX_SRC_TPM0_CH_1);
+
+    NVIC_SetVector(DMA0_IRQn, (uint32_t)&DMA0_IRQHandler);
+    NVIC_EnableIRQ(DMA0_IRQn);
+}
+
+// class static
+
+/// Configure TPM0 to do two different PWM periods at 800kHz rate
+void WS2811::tpm_init()
+{
+    // set up TPM0 for proper period (800 kHz = 1.25 usec ±600nsec)
+    TPM_Type volatile *tpm = TPM0;
+    tpm->SC = TPM_SC_DMA_MASK          // enable DMA
+              | TPM_SC_TOF_MASK        // reset TOF flag if set
+              | TPM_SC_CMOD(0)         // disable clocks
+              | TPM_SC_PS(0);          // 48MHz / 1 = 48MHz clock
+    tpm->MOD = tpm_period - 1;         // 48MHz / 800kHz
+
+    // No Interrupts; High True pulses on Edge Aligned PWM
+    tpm->CONTROLS[0].CnSC = TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK | TPM_CnSC_DMA_MASK;
+    tpm->CONTROLS[1].CnSC = TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK | TPM_CnSC_DMA_MASK;
+
+    // set TPM0 channel 0 for 0.35 usec (±150nsec) (0 code)
+    // 1.25 usec * 1/3 = 417 nsec
+    tpm->CONTROLS[0].CnV = tpm_p0_period;
+
+    // set TPM0 channel 1 for 0.7 usec (±150nsec) (1 code)
+    // 1.25 usec * 2/3 = 833 nsec
+    tpm->CONTROLS[1].CnV = tpm_p1_period;
+
+    NVIC_SetVector(TPM0_IRQn, (uint32_t)&TPM0_IRQHandler);
+    NVIC_EnableIRQ(TPM0_IRQn);
+}
+
+WS2811::WS2811(unsigned n, unsigned pinNumber)
+    : LedStrip(n)
+    , pinMask(1U << pinNumber)
+{
+    enabledPins |= pinMask;
+    initialized = false;
+}
+
+// class static
+void WS2811::startDMA()
+{
+    hw_init();
+    
+    wait_for_dma_done();
+    dma_done = false;
+
+    DMA_Type volatile * dma   = DMA0;
+    TPM_Type volatile *tpm   = TPM0;
+    uint32_t nBytes = sizeof(dmaData.start_t1_low)
+                      + sizeof(dmaData.dmaWords)
+                      + sizeof(dmaData.trailing_zeros_1);
+
+    tpm->SC = TPM_SC_DMA_MASK        // enable DMA
+              | TPM_SC_TOF_MASK  // reset TOF flag if set
+              | TPM_SC_CMOD(0)   // disable clocks
+              | TPM_SC_PS(0);    // 48MHz / 1 = 48MHz clock
+    tpm->MOD = tpm_period - 1;       // 48MHz / 800kHz
+
+    tpm->CNT = tpm_p0_period - 2 ;
+    tpm->STATUS = 0xFFFFFFFF;
+
+    dma->DMA[DMA_CHAN_START].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+    dma->DMA[DMA_CHAN_0_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+    dma->DMA[DMA_CHAN_1_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+
+    // t=0: all outputs go high
+    // triggered by TPM0_Overflow
+    // source is one word of 0 then 24 x 0xffffffff, then another 0 word
+    dma->DMA[DMA_CHAN_START].SAR     = (uint32_t)(void*)dmaData.start_t0_high;
+    dma->DMA[DMA_CHAN_START].DSR_BCR = DMA_DSR_BCR_BCR_MASK & nBytes; // length of transfer in bytes
+
+    // t=tpm_p0_period: some outputs (the 0 bits) go low.
+    // Triggered by TPM0_CH0
+    // Start 2 words before the actual data to avoid garbage pulses.
+    dma->DMA[DMA_CHAN_0_LOW].SAR     = (uint32_t)(void*)dmaData.start_t1_low; // set source address
+    dma->DMA[DMA_CHAN_0_LOW].DSR_BCR = DMA_DSR_BCR_BCR_MASK & nBytes; // length of transfer in bytes
+
+    // t=tpm_p1_period: all outputs go low.
+    // Triggered by TPM0_CH1
+    // source is constant 0x00000000 (first word of dmaWords)
+    dma->DMA[DMA_CHAN_1_LOW].SAR     = (uint32_t)(void*)dmaData.start_t1_low; // set source address
+    dma->DMA[DMA_CHAN_1_LOW].DSR_BCR = DMA_DSR_BCR_BCR_MASK & nBytes; // length of transfer in bytes
+
+    dma->DMA[DMA_CHAN_0_LOW].DAR
+    = dma->DMA[DMA_CHAN_1_LOW].DAR
+      = dma->DMA[DMA_CHAN_START].DAR
+        = (uint32_t)(void*)&IO_GPIO->PDOR;
+
+    SET_DEBUG;
+
+    dma->DMA[DMA_CHAN_0_LOW].DCR     = DMA_DCR_EINT_MASK // enable interrupt on end of transfer
+                                       | DMA_DCR_ERQ_MASK
+                                       | DMA_DCR_D_REQ_MASK // clear ERQ on end of transfer
+                                       | DMA_DCR_SINC_MASK // increment source each transfer
+                                       | DMA_DCR_CS_MASK
+                                       | DMA_DCR_SSIZE(0) // 32-bit source transfers
+                                       | DMA_DCR_DSIZE(0); // 32-bit destination transfers
+
+    dma->DMA[DMA_CHAN_1_LOW].DCR     = DMA_DCR_EINT_MASK // enable interrupt on end of transfer
+                                       | DMA_DCR_ERQ_MASK
+                                       | DMA_DCR_D_REQ_MASK // clear ERQ on end of transfer
+                                       | DMA_DCR_CS_MASK
+                                       | DMA_DCR_SSIZE(0) // 32-bit source transfers
+                                       | DMA_DCR_DSIZE(0); // 32-bit destination transfers
+
+    dma->DMA[DMA_CHAN_START].DCR     = DMA_DCR_EINT_MASK // enable interrupt on end of transfer
+                                       | DMA_DCR_ERQ_MASK
+                                       | DMA_DCR_D_REQ_MASK // clear ERQ on end of transfer
+                                       | DMA_DCR_SINC_MASK // increment source each transfer
+                                       | DMA_DCR_CS_MASK
+                                       | DMA_DCR_SSIZE(0) // 32-bit source transfers
+                                       | DMA_DCR_DSIZE(0);
+
+    tpm->SC |= TPM_SC_CMOD(1);         // enable internal clocking
+}
+
+void WS2811::writePixel(unsigned n, uint8_t *p)
+{
+    uint32_t *dest = dmaData.dmaWords + n * BITS_PER_RGB;
+    writeByte(*p++, pinMask, dest + 0); // G
+    writeByte(*p++, pinMask, dest + 8); // R
+    writeByte(*p, pinMask, dest + 16); // B
+}
+
+// class static
+void WS2811::writeByte(uint8_t byte, uint32_t mask, uint32_t *dest)
+{
+    for (uint8_t bm = 0x80; bm; bm >>= 1) {
+        // MSBit first
+        if (byte & bm)
+            *dest |= mask;
+        else
+            *dest &= ~mask;
+        dest++;
+    }
+}
+
+void WS2811::begin()
+{
+    blank();
+    show();
+}
+
+void WS2811::blank()
+{
+    memset(pixels, 0x00, numPixelBytes());
+
+#if DEBUG
+    for (unsigned i = DMA_LEADING_ZEROS; i < DMA_LEADING_ZEROS + BITS_PER_RGB; i++)
+        dmaData.dmaWords[i] = DEBUG_MASK;
+#else
+    memset(dmaData.dmaWords, 0x00, sizeof(dmaData.dmaWords));
+#endif
+}
+
+void WS2811::show()
+{
+
+    uint16_t i, n = numPixels(); // 3 bytes per LED
+    uint8_t *p = pixels;
+
+    for (i=0; i<n; i++ ) {
+        writePixel(i, p);
+        p += 3;
+    }
+}
+
+extern "C" void DMA0_IRQHandler()
+{
+    DMA_Type volatile *dma = DMA0;
+    TPM_Type volatile *tpm = TPM0;
+
+    uint32_t db;
+
+    db = dma->DMA[DMA_CHAN_0_LOW].DSR_BCR;
+    if (db & DMA_DSR_BCR_DONE_MASK) {
+        dma->DMA[DMA_CHAN_0_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+    }
+
+    db = dma->DMA[DMA_CHAN_1_LOW].DSR_BCR;
+    if (db & DMA_DSR_BCR_DONE_MASK) {
+        dma->DMA[DMA_CHAN_1_LOW].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+    }
+
+    db = dma->DMA[DMA_CHAN_START].DSR_BCR;
+    if (db & DMA_DSR_BCR_DONE_MASK) {
+        dma->DMA[DMA_CHAN_START].DSR_BCR = DMA_DSR_BCR_DONE_MASK; // clear/reset DMA status
+    }
+
+    tpm->SC = TPM_SC_TOF_MASK;  // reset TOF flag; disable internal clocking
+
+    SET_DEBUG;
+
+    // set TPM0 to interrrupt after guardtime
+    tpm->MOD = guardtime_period - 1; // 48MHz * 55 usec
+    tpm->CNT = 0;
+    tpm->SC  = TPM_SC_PS(0)        // 48MHz / 1 = 48MHz clock
+               | TPM_SC_TOIE_MASK  // enable interrupts
+               | TPM_SC_CMOD(1);   // and internal clocking
+}
+
+extern "C" void TPM0_IRQHandler()
+{
+    TPM0->SC = 0; // disable internal clocking
+    TPM0->SC = TPM_SC_TOF_MASK;        
+    RESET_DEBUG;
+    WS2811::dma_done = true;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2811.h	Sat Jan 04 00:40:08 2014 +0000
@@ -0,0 +1,63 @@
+// Mbed library to control WS2801-based RGB LED Strips
+// some portions (c) 2011 Jelmer Tiete
+// This library is ported from the Arduino implementation of Adafruit Industries
+// found at: http://github.com/adafruit/LPD8806
+// and their strips: http://www.adafruit.com/products/306
+// Released under the MIT License: http://mbed.org/license/mit
+//
+/*****************************************************************************/
+
+// Heavily modified by Jas Strong, 2012-10-04
+// Changed to use a virtual base class and to use software SPI.
+//
+// Modified by Ned Konz, December 2013.
+// Using three-phase DMA ala Paul Stoffegren's version.
+
+#ifndef MBED_WS2811_H
+#define MBED_WS2811_H
+
+#include "mbed.h"
+#include "LedStrip.h"
+
+#define MAX_LEDS_PER_STRIP 60
+
+extern "C" void DMA0_IRQHandler();
+extern "C" void TPM0_IRQHandler();
+
+class WS2811 : public LedStrip
+{
+public:
+    WS2811(unsigned n, unsigned pinNumber);
+
+    virtual void begin();
+    virtual void show();
+    virtual void blank();
+
+    static void startDMA();
+
+private:
+    uint32_t pinMask;
+
+    void writePixel(unsigned n, uint8_t *p);
+
+    // Class Static:
+
+    static bool initialized;
+    static uint32_t enabledPins;
+    static volatile bool dma_done;
+    static void wait_for_dma_done() { while (!dma_done) __WFI(); }
+
+    static void writeByte(uint8_t byte, uint32_t mask, uint32_t *dest);
+
+    static void hw_init();
+        static void io_init();
+        static void clock_init();
+        static void dma_init();
+        static void tpm_init();
+        static void dma_data_init();
+        
+    friend void TPM0_IRQHandler();
+};
+
+#endif
+