Diff: WS2811.cpp

Revision:

8:e3249c2b7607

Child:

9:dd524af149e6

--- /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;
+}