Diff: WS2801.cpp

Revision:

6:7aebe547f0f0

Parent:

5:70ded6500cd3

Child:

7:3025f0e0d70a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WS2801.cpp	Thu Oct 11 08:34:21 2012 +0000
@@ -0,0 +1,114 @@
+// 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();
+}
+
+// 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;
+}