Revision 0:0b79cafcb387, committed 2015-02-12

Comitter:

bridadan

Date:

Thu Feb 12 19:17:10 2015 +0000

Child:

1:aadbf08c62a2

Commit message:

Driver for the WS2812 LED driver. Uses bit banging and relies on nops for timing. Number of nops can be varied to potentially accommodate different platforms. Currently tested on the K64F.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2812.cpp	Thu Feb 12 19:17:10 2015 +0000
@@ -0,0 +1,128 @@
+#include "WS2812.h"
+
+WS2812::WS2812(PinName d, int size) : __gpo(d)
+{
+    __size = size;
+    __transmitBuf = new bool[size * FRAME_SIZE];
+    __use_II = 0; // 0=off,1=use global,2=per pixel
+    __II = 0xFF; // set global intensity to full
+    __outPin = d;
+    
+    // Default values designed for K64f. Assumes GPIO toggle takes ~0.4us
+    setDelays(0, 5, 5, 0);
+}
+
+
+WS2812::~WS2812()
+{
+    delete[] __transmitBuf;
+}
+
+void WS2812::setDelays(int zeroHigh, int zeroLow, int oneHigh, int oneLow) {
+    __zeroHigh = zeroHigh;
+    __zeroLow = zeroLow;
+    __oneHigh = oneHigh;
+    __oneLow = oneLow;
+}
+
+void WS2812::__loadBuf(int buf[],int r_offset, int g_offset, int b_offset) {
+    for (int i = 0; i < __size; i++) {
+        int color = 0;
+               
+        color |= ((buf[(i+g_offset)%__size] & 0x0000FF00));
+        color |= ((buf[(i+r_offset)%__size] & 0x00FF0000));
+        color |=  (buf[(i+b_offset)%__size] & 0x000000FF);
+        color |= (buf[i] & 0xFF000000);
+        
+        // Outut format : GGRRBB
+        // Inout format : IIRRGGBB
+        unsigned char agrb[4] = {0x0, 0x0, 0x0, 0x0};
+    
+        unsigned char sf; // scaling factor for  II
+    
+        // extract colour fields from incoming
+        // 0 = green, 1 = red, 2 = blue, 3 = brightness        
+        agrb[0] = (color & 0x0000FF00) >> 8;
+        agrb[1] = (color & 0x00FF0000) >> 16;
+        agrb[2] = color  & 0x000000FF;
+        agrb[3] = (color & 0xFF000000) >> 24;
+    
+        // set and intensity scaling factor (global, per pixel, none)
+        if (__use_II == 1) {
+            sf = __II;
+        } else if (__use_II == 2) {
+            sf = agrb[3];
+        } else {
+            sf = 0xFF;
+        }
+        
+        // Apply the scaling factor to each othe colour components
+        for (int clr = 0; clr < 3; clr++) {
+            agrb[clr] = ((agrb[clr] * sf) >> 8);
+            
+            for (int j = 0; j < 8; j++) {
+                if (((agrb[clr] << j) & 0x80) == 0x80) {
+                    // Bit is set (checks MSB fist)
+                    __transmitBuf[(i * FRAME_SIZE) + (clr * 8) + j] = 1;
+                } else {
+                    // Bit is clear
+                    __transmitBuf[(i * FRAME_SIZE) + (clr * 8) + j] = 0;
+                }
+            }
+        }
+    }
+}
+
+void WS2812::write(int buf[]) {
+    write_offsets(buf, 0, 0, 0);
+}
+
+void WS2812::write_offsets (int buf[],int r_offset, int g_offset, int b_offset) {
+    int i, j;
+    
+    __loadBuf(buf, r_offset, g_offset, b_offset);
+
+    for (i = 0; i < FRAME_SIZE * __size; i++) {
+        j = 0;
+        if (__transmitBuf[i]){
+            __gpo = 1;
+            for (; j < __oneHigh; j++) {
+                __nop();
+            }
+            __gpo = 0;
+            for (; j < __oneLow; j++) {
+                __nop();
+            }
+        } else {
+            __gpo = 1;
+            for (; j < __zeroHigh; j++) {
+                __nop();
+            }
+            __gpo = 0;
+            for (; j < __zeroLow; j++) {
+                __nop();
+            }
+        }
+    }
+}
+
+
+void WS2812::useII(int d)
+{
+    if (d > 0) {
+        __use_II = d;
+    } else {
+        __use_II = 0;
+    }
+}
+
+void WS2812::setII(unsigned char II)
+{
+    __II = II;
+}
+
+
+
+
+
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2812.h	Thu Feb 12 19:17:10 2015 +0000
@@ -0,0 +1,70 @@
+/* Copyright (c) 2012 cstyles, MIT License
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+ * and associated documentation files (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge, publish, distribute,
+ * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+ * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef WS2812_H
+#define WS2812_H
+
+#include "mbed.h"
+
+#define WS1 0x38
+#define WS0 0x30
+#define SPICLK 5000000
+#define FRAME_SIZE 24
+
+
+//!Library for the WS2812 RGB LED with integrated controller
+/*!
+The WS2812 is controller that is built into a range of LEDs
+*/
+class WS2812
+{
+public:
+    //!Creates an instance of the class.
+    /*!
+    Connect WS2812 address addr using digital pins
+    */
+    WS2812(PinName d, int size);
+
+    /*!
+    Destroys instance.
+    */
+    ~WS2812();
+    
+    void setDelays(int zeroHigh, int zeroLow, int oneHigh, int oneLow);
+
+    void write(int buf[]);
+    void write_offsets(int buf[],int r_offset=0, int g_offset=0, int b_offset=0);
+
+    void useII(int d);
+    void setII(unsigned char II);
+    
+
+
+private:
+
+    int __size;
+    int __zeroHigh, __zeroLow, __oneHigh, __oneLow;
+    unsigned char __II;
+    int __use_II;
+    bool *__transmitBuf;
+    void __loadBuf(int buf[],int r_offset=0, int g_offset=0, int b_offset=0);
+    PinName __outPin;
+    DigitalOut __gpo;
+};
+
+#endif
\ No newline at end of file