Revision 0:afc41b8e2360, committed 2015-03-05

Comitter:

rosienej

Date:

Thu Mar 05 19:02:07 2015 +0000

Child:

1:2d02f55d47c5

Commit message:

A simple example to drive an APA-102 Led Strip

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Mar 05 19:02:07 2015 +0000
@@ -0,0 +1,89 @@
+#include "mbed.h"
+
+SPI spi(PTA16, PTA17, PTA15); // mosi, miso, sclk
+
+// This function was downloaded from:
+// http://blog.saikoled.com/post/43693602826/why-every-led-light-should-be-using-hsi 
+// Blog Post attributed to Brian Neltner
+
+// Function example takes H, S, I, and a pointer to the 
+// returned RGB colorspace converted vector. It should
+// be initialized with:
+//
+// int rgb[3];
+//
+// in the calling function. After calling hsi2rgb
+// the vector rgb will contain red, green, and blue
+// calculated values.
+// 
+
+void hsi2rgb(float H, float S, float I, int* rgb) {
+
+  int r, g, b;
+  H = fmod(H,360); // cycle H around to 0-360 degrees
+  H = 3.14159*H/(float)180; // Convert to radians.
+  S = S>0?(S<1?S:1):0; // clamp S and I to interval [0,1]
+  I = I>0?(I<1?I:1):0;
+    
+  // Math! Thanks in part to Kyle Miller.
+  if(H < 2.09439) {
+    r = 255*I/3*(1+S*cos(H)/cos(1.047196667-H));
+    g = 255*I/3*(1+S*(1-cos(H)/cos(1.047196667-H)));
+    b = 255*I/3*(1-S);
+  } else if(H < 4.188787) {
+    H = H - 2.09439;
+    g = 255*I/3*(1+S*cos(H)/cos(1.047196667-H));
+    b = 255*I/3*(1+S*(1-cos(H)/cos(1.047196667-H)));
+    r = 255*I/3*(1-S);
+  } else {
+    H = H - 4.188787;
+    b = 255*I/3*(1+S*cos(H)/cos(1.047196667-H));
+    r = 255*I/3*(1+S*(1-cos(H)/cos(1.047196667-H)));
+    g = 255*I/3*(1-S);
+  }
+  rgb[0]=r;
+  rgb[1]=g;
+  rgb[2]=b;
+}
+
+
+int main()
+{
+    // Quick example to drive an APA-102 LED Strip from a FRDM-KL46z
+    
+    // http://www.insomnialighting.com/catalog/index.php?main_page=product_info&products_id=61
+    // Wire the unit up to SPI, common ground and give it 5 volt power.
+    
+    // Shift through the spectrum, slowly rotate.
+    
+    // Setup the spi for 8 bit data, high steady state clock,
+    // second edge capture, with a 1MHz clock rate
+    spi.format(8,3);
+    spi.frequency(1000000);
+    int rgb[3]; 
+    const int N=288;  // Number of APA-102 Elements
+    
+    int colors=0x000000;
+    while (true) {
+        spi.write(0X00);  // Start
+        spi.write(0X00);
+        spi.write(0X00);
+        spi.write(0X00);
+        
+        
+        for(int i=0;i<N;i++)
+        {   spi.write(0XEF);  // 0xE0 + 1F, Frame + max brightness
+            hsi2rgb(1.0*(i+colors), 0.8, 0.8,rgb);
+            spi.write(0XFF&rgb[0]);  // 0xE0 + 1F, Frame + max brightness
+            spi.write(0XFF&rgb[1]);  // 0xE0 + 1F, Frame + max brightness
+            spi.write(0XFF&rgb[2]);  // 0xE0 + 1F, Frame + max brightness
+            
+            } 
+        
+        spi.write(0XFF); // Stop
+        spi.write(0XFF);
+        spi.write(0XFF);
+        spi.write(0XFF);  
+        colors++;
+    }
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Thu Mar 05 19:02:07 2015 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/9ad691361fac
\ No newline at end of file