Revision 8:e3249c2b7607, committed 2012-11-10

Comitter:

heroic

Date:

Sat Nov 10 05:58:14 2012 +0000

Parent:

7:3025f0e0d70a

Child:

9:dd524af149e6

Commit message:

Initial commit for first cut of WS2811 driver. These are one-wire style devices, so we do some timing mojo.

Changed in this revision

--- a/WS2801.cpp	Fri Oct 12 04:16:40 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,123 +0,0 @@
-// Mbed library to control LPD8806-based RGB LED Strips
-// (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
-//
-// Parameterized and modified to use soft SPI.
-// Jas Strong <jasmine@electronpusher.org>
-/*****************************************************************************/
-
-#include "LedStrip.h"
-#include "WS2801.h"
-
-WS2801::WS2801(PinName dataPin, PinName clockPin, int n) :
-    dat(dataPin),
-    clk(clockPin) {
-    // Allocate 3 bytes per pixel:
-    numLEDs = n;
-    if ((pixels = (uint8_t *)malloc(numLEDs * 3))) {
-        memset(pixels, 0x00, numLEDs * 3); // Init to RGB 'off' state
-    }
-    guardtime.start();
-}
-
-/*
- *  Soft SPI clock-out implementation (CPOL = 0, CPHA = 0).
- *  Certainly not the fastest in the world but it'll do.
- *  Gets about 3.6 MHz;  could get several times as much
- *  using the bitbands directly  - jas.
- */
- 
-void WS2801::write(uint8_t byte) {
-    for (int i=0; i<8; i++) {
-        clk = 0;
-        wait_us(WS2801_DELAY);
-        dat = (byte & 0x80);
-        clk = 1;
-        wait_us(WS2801_DELAY);
-        byte <<= 1;
-    }
-    clk = 0;
-}
-
-void WS2801::begin(void) {
-    blank();
-    show();
-}
-
-uint16_t WS2801::numPixels(void) {
-    return numLEDs;
-}
-
-void WS2801::blank(void) {
-    memset(pixels, 0x00, numLEDs * 3);
-}
-
-// This is how data is pushed to the strip.  Unfortunately, the company
-// that makes the chip didnt release the  protocol document or you need
-// to sign an NDA or something stupid like that, but we reverse engineered
-// this from a strip controller and it seems to work very nicely!
-void WS2801::show(void) {
-    uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED
-    while (guardtime.read_us() < 500)
-        /* spin */;
-    for (i=0; i<nl3; i++ ) {
-        write(pixels[i]);
-    }
-
-    guardtime.reset();
-}
-
-
-uint32_t WS2801::total_luminance(void) {
-    uint32_t running_total;
-    running_total = 0;
-    for (int i=0; i<numLEDs*3; i++)
-        running_total += pixels[i];
-    return running_total;
-}
-
-// Convert R,G,B to combined 32-bit color
-uint32_t WS2801::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 WS2801::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 WS2801::setPixelR(uint16_t n, uint8_t r) {
-    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
-
-    pixels[n*3+1] = r;
-}
-
-void WS2801::setPixelG(uint16_t n, uint8_t g) {
-    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
-
-    pixels[n*3] = g;
-}
-
-void WS2801::setPixelB(uint16_t n, uint8_t b) {
-    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
-
-    pixels[n*3+2] = b;
-}
-
-void WS2801::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;
-}

--- a/WS2801.h	Fri Oct 12 04:16:40 2012 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,46 +0,0 @@
-// 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.
-
-#include "mbed.h"
-#include "LedStrip.h"
-#ifndef MBED_WS2801_H
-#define MBED_WS2801_H
-
-#define WS2801_DELAY 1
-
-class WS2801 : public LedStrip {
-
- public:
-
-  WS2801(PinName dataPin, PinName clockPin, int n);
-  virtual void begin(void);
-  virtual void show(void);
-  virtual void blank(void);
-  virtual void setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b);
-  virtual void setPixelB(uint16_t n, uint8_t b);
-  virtual void setPixelG(uint16_t n, uint8_t g);
-  virtual void setPixelR(uint16_t n, uint8_t r);
-  virtual void setPixelColor(uint16_t n, uint32_t c);
-  virtual uint16_t numPixels(void);
-  virtual uint32_t Color(uint8_t, uint8_t, uint8_t);
-  virtual uint32_t total_luminance(void);
-
- private:
-  DigitalOut dat;
-  DigitalOut clk;
-  void write(uint8_t byte);
-  uint8_t *pixels;     // Holds LED color values
-  uint16_t numLEDs;     // Number of RGB LEDs in strand
-  Timer guardtime;
-    
-};
-#endif
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2811.cpp	Sat Nov 10 05:58:14 2012 +0000
@@ -0,0 +1,137 @@
+// WS2811 driver, kinda.
+//
+// Parameterized and modified to use soft SPI.
+// Jas Strong <jasmine@electronpusher.org>
+/*****************************************************************************/
+
+#include "LedStrip.h"
+#include "WS2811.h"
+
+WS2811::WS2811(PinName dataPin, PinName clockPin, int n) :
+    dat(dataPin),
+    clk(clockPin) {
+    // Allocate 3 bytes per pixel:
+    numLEDs = n;
+    if ((pixels = (uint8_t *)malloc(numLEDs * 3))) {
+        memset(pixels, 0x00, numLEDs * 3); // Init to RGB 'off' state
+    }
+    // calibrate delay loops for NRZ 
+    int i;
+    guardtime.start();
+    for (i=0; i<1000; i++)
+        /* do nothing */;
+    i=guardtime.read_us();
+    printf("ws2811:  1000 iters took %d usec.\n", i);
+    bogocal = (1000 / (i*2.4)); // iterations per bitcell (417 nsec)
+    printf("ws2811:  calibrating to %d bogojiffies.\n", bogocal);
+}
+
+/*
+ *  These chips use a one-wire protocol based on a sort of NRZ signalling- jas.
+ */
+ 
+void WS2811::write(uint8_t byte) {
+    for (int i=0; i<8; i++) {
+        if (byte & 0x80)
+            writebit(1);
+        else
+            writebit(0);
+        byte <<= 1;
+    }
+}
+
+inline void WS2811::celldelay(void) {
+    for (int i = 0; i<bogocal; i++)
+        /* do nothing */ ;
+}
+
+void WS2811::writebit(bool bit) {
+    // first cell is always 1
+    dat = 1;
+    celldelay();
+    if (bit) {
+        celldelay();
+    } else {
+        dat=0;
+        celldelay();
+    }
+    // last cell is always 0
+    dat=0;
+    celldelay();
+}
+
+void WS2811::begin(void) {
+    blank();
+    show();
+}
+
+uint16_t WS2811::numPixels(void) {
+    return numLEDs;
+}
+
+void WS2811::blank(void) {
+    memset(pixels, 0x00, numLEDs * 3);
+}
+
+void WS2811::show(void) {
+    uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED
+    while (guardtime.read_us() < 50)
+        /* spin */;
+    for (i=0; i<nl3; i++ ) {
+        write(pixels[i]);
+    }
+
+    guardtime.reset();
+}
+
+
+uint32_t WS2811::total_luminance(void) {
+    uint32_t running_total;
+    running_total = 0;
+    for (int i=0; i<numLEDs*3; i++)
+        running_total += pixels[i];
+    return running_total;
+}
+
+// Convert R,G,B to combined 32-bit color
+uint32_t WS2811::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 WS2811::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 WS2811::setPixelR(uint16_t n, uint8_t r) {
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3+1] = r;
+}
+
+void WS2811::setPixelG(uint16_t n, uint8_t g) {
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3] = g;
+}
+
+void WS2811::setPixelB(uint16_t n, uint8_t b) {
+    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
+
+    pixels[n*3+2] = b;
+}
+
+void WS2811::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/WS2811.h	Sat Nov 10 05:58:14 2012 +0000
@@ -0,0 +1,48 @@
+// 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.
+
+#include "mbed.h"
+#include "LedStrip.h"
+#ifndef MBED_WS2811_H
+#define MBED_WS2811_H
+
+
+class WS2811 : public LedStrip {
+
+ public:
+
+  WS2811(PinName dataPin, PinName clockPin, int n);
+  virtual void begin(void);
+  virtual void show(void);
+  virtual void blank(void);
+  virtual void setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b);
+  virtual void setPixelB(uint16_t n, uint8_t b);
+  virtual void setPixelG(uint16_t n, uint8_t g);
+  virtual void setPixelR(uint16_t n, uint8_t r);
+  virtual void setPixelColor(uint16_t n, uint32_t c);
+  virtual uint16_t numPixels(void);
+  virtual uint32_t Color(uint8_t, uint8_t, uint8_t);
+  virtual uint32_t total_luminance(void);
+
+ private:
+  DigitalOut dat;
+  DigitalOut clk;
+  void write(uint8_t byte);
+  void writebit(bool bit);
+  void celldelay(void);
+  uint8_t *pixels;     // Holds LED color values
+  uint16_t numLEDs;     // Number of RGB LEDs in strand
+  Timer guardtime;
+  uint32_t bogocal;
+    
+};
+#endif
\ No newline at end of file