Heroic Robotics / SD600A

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Fork of SD600A by Heroic Robotics

LPD8806.cpp@4:0b75eb84a6d2, 2012-10-05 (annotated)

Committer:
heroic
Date:
Fri Oct 05 05:41:39 2012 +0000
Revision:
4:0b75eb84a6d2
Parent:
3:a415f73507c9 
Change to use virtual base class

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ehbmbed2 0:12e734116fea 1 // Mbed library to control LPD8806-based RGB LED Strips
ehbmbed2 0:12e734116fea 2 // (c) 2011 Jelmer Tiete
ehbmbed2 0:12e734116fea 3 // This library is ported from the Arduino implementation of Adafruit Industries
ehbmbed2 0:12e734116fea 4 // found at: http://github.com/adafruit/LPD8806
ehbmbed2 0:12e734116fea 5 // and their strips: http://www.adafruit.com/products/306
ehbmbed2 0:12e734116fea 6 // Released under the MIT License: http://mbed.org/license/mit
ehbmbed2 1:6ebd3ac910b6 7 //
heroic 2:af5af64e114d 8 // Parameterized and modified to use soft SPI.
heroic 2:af5af64e114d 9 // Jas Strong <jasmine@electronpusher.org>
ehbmbed2 0:12e734116fea 10 /*****************************************************************************/
ehbmbed2 0:12e734116fea 11
heroic 4:0b75eb84a6d2 12 #include "LedStrip.h"
ehbmbed2 0:12e734116fea 13 #include "LPD8806.h"
ehbmbed2 0:12e734116fea 14
heroic 2:af5af64e114d 15 LPD8806::LPD8806(PinName dataPin, PinName clockPin, int n) :
heroic 2:af5af64e114d 16 dat(dataPin),
heroic 2:af5af64e114d 17 clk(clockPin) {
ehbmbed2 0:12e734116fea 18 // Allocate 3 bytes per pixel:
heroic 2:af5af64e114d 19 numLEDs = n;
heroic 3:a415f73507c9 20 if ((pixels = (uint8_t *)malloc(numLEDs * 3))) {
ehbmbed2 0:12e734116fea 21 memset(pixels, 0x80, numLEDs * 3); // Init to RGB 'off' state
ehbmbed2 0:12e734116fea 22 }
ehbmbed2 0:12e734116fea 23 }
ehbmbed2 0:12e734116fea 24
heroic 2:af5af64e114d 25 /*
heroic 2:af5af64e114d 26 * Soft SPI clock-out implementation (CPOL = 0, CPHA = 0).
heroic 2:af5af64e114d 27 * Certainly not the fastest in the world but it'll do.
heroic 2:af5af64e114d 28 * Gets about 3.6 MHz; could get several times as much
heroic 2:af5af64e114d 29 * using the bitbands directly - jas.
heroic 2:af5af64e114d 30 */
heroic 2:af5af64e114d 31
heroic 2:af5af64e114d 32 void LPD8806::write(uint8_t byte) {
heroic 2:af5af64e114d 33 for (int i=0; i<8; i++) {
heroic 2:af5af64e114d 34 clk = 0;
heroic 2:af5af64e114d 35 dat = (byte & 0x80);
heroic 2:af5af64e114d 36 clk = 1;
heroic 2:af5af64e114d 37 byte <<= 1;
heroic 2:af5af64e114d 38 }
heroic 2:af5af64e114d 39 clk = 0;
heroic 2:af5af64e114d 40 }
ehbmbed2 0:12e734116fea 41
heroic 2:af5af64e114d 42 void LPD8806::begin(void) {
ehbmbed2 0:12e734116fea 43
ehbmbed2 0:12e734116fea 44 // Issue initial latch to 'wake up' strip (latch length varies w/numLEDs)
ehbmbed2 0:12e734116fea 45 writezeros(3 * ((numLEDs + 63) / 64));
ehbmbed2 0:12e734116fea 46 }
ehbmbed2 0:12e734116fea 47
ehbmbed2 0:12e734116fea 48 uint16_t LPD8806::numPixels(void) {
ehbmbed2 0:12e734116fea 49 return numLEDs;
ehbmbed2 0:12e734116fea 50 }
ehbmbed2 0:12e734116fea 51
ehbmbed2 0:12e734116fea 52 void LPD8806::writezeros(uint16_t n) {
heroic 2:af5af64e114d 53 while (n--) write(0x00);
heroic 2:af5af64e114d 54 }
heroic 2:af5af64e114d 55
heroic 2:af5af64e114d 56 void LPD8806::blank(void) {
heroic 2:af5af64e114d 57 memset(pixels, 0x80, numLEDs * 3);
ehbmbed2 0:12e734116fea 58 }
ehbmbed2 0:12e734116fea 59
ehbmbed2 0:12e734116fea 60 // This is how data is pushed to the strip. Unfortunately, the company
ehbmbed2 0:12e734116fea 61 // that makes the chip didnt release the protocol document or you need
ehbmbed2 0:12e734116fea 62 // to sign an NDA or something stupid like that, but we reverse engineered
ehbmbed2 0:12e734116fea 63 // this from a strip controller and it seems to work very nicely!
ehbmbed2 0:12e734116fea 64 void LPD8806::show(void) {
ehbmbed2 0:12e734116fea 65 uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED
ehbmbed2 0:12e734116fea 66
ehbmbed2 0:12e734116fea 67 for (i=0; i<nl3; i++ ) {
heroic 2:af5af64e114d 68 write(pixels[i]);
ehbmbed2 0:12e734116fea 69 }
ehbmbed2 0:12e734116fea 70
ehbmbed2 0:12e734116fea 71 // Write latch at end of data; latch length varies with number of LEDs
ehbmbed2 0:12e734116fea 72 writezeros(3 * ((numLEDs + 63) / 64));
ehbmbed2 0:12e734116fea 73 }
ehbmbed2 0:12e734116fea 74
ehbmbed2 0:12e734116fea 75 // Convert R,G,B to combined 32-bit color
ehbmbed2 0:12e734116fea 76 uint32_t LPD8806::Color(uint8_t r, uint8_t g, uint8_t b) {
ehbmbed2 0:12e734116fea 77 // Take the lowest 7 bits of each value and append them end to end
ehbmbed2 0:12e734116fea 78 // We have the top bit set high (its a 'parity-like' bit in the protocol
ehbmbed2 0:12e734116fea 79 // and must be set!)
ehbmbed2 0:12e734116fea 80 return 0x808080 | ((uint32_t)g << 16) | ((uint32_t)r << 8) | (uint32_t)b;
ehbmbed2 0:12e734116fea 81 }
ehbmbed2 0:12e734116fea 82
ehbmbed2 0:12e734116fea 83 // store the rgb component in our array
ehbmbed2 0:12e734116fea 84 void LPD8806::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b) {
ehbmbed2 0:12e734116fea 85 if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
ehbmbed2 0:12e734116fea 86
ehbmbed2 0:12e734116fea 87 pixels[n*3 ] = g | 0x80;
ehbmbed2 0:12e734116fea 88 pixels[n*3+1] = r | 0x80;
ehbmbed2 0:12e734116fea 89 pixels[n*3+2] = b | 0x80;
ehbmbed2 0:12e734116fea 90 }
ehbmbed2 0:12e734116fea 91
heroic 2:af5af64e114d 92 void LPD8806::setPixelR(uint16_t n, uint8_t r) {
heroic 2:af5af64e114d 93 if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
heroic 2:af5af64e114d 94
heroic 2:af5af64e114d 95 pixels[n*3+1] = r | 0x80;
heroic 2:af5af64e114d 96 }
heroic 2:af5af64e114d 97
heroic 2:af5af64e114d 98 void LPD8806::setPixelG(uint16_t n, uint8_t g) {
heroic 2:af5af64e114d 99 if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
heroic 2:af5af64e114d 100
heroic 2:af5af64e114d 101 pixels[n*3] = g | 0x80;
heroic 2:af5af64e114d 102 }
heroic 2:af5af64e114d 103
heroic 2:af5af64e114d 104 void LPD8806::setPixelB(uint16_t n, uint8_t b) {
heroic 2:af5af64e114d 105 if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
heroic 2:af5af64e114d 106
heroic 2:af5af64e114d 107 pixels[n*3+2] = b | 0x80;
heroic 2:af5af64e114d 108 }
heroic 2:af5af64e114d 109
ehbmbed2 0:12e734116fea 110 void LPD8806::setPixelColor(uint16_t n, uint32_t c) {
ehbmbed2 0:12e734116fea 111 if (n >= numLEDs) return; // '>=' because arrays are 0-indexed
ehbmbed2 0:12e734116fea 112
ehbmbed2 0:12e734116fea 113 pixels[n*3 ] = (c >> 16) | 0x80;
ehbmbed2 0:12e734116fea 114 pixels[n*3+1] = (c >> 8) | 0x80;
ehbmbed2 0:12e734116fea 115 pixels[n*3+2] = c | 0x80;
ehbmbed2 0:12e734116fea 116 }