Andrew Lindsay / Adafruit_WS2801

A conversion of the excellent Adafruit WS2801 library for Arduino to work on mbed

Dependents:   WiFiDipCortex_Cheerlights

Adafruit_WS2801.cpp@0:582e1b9c1cc1, 2013-03-08 (annotated)

Committer:
SomeRandomBloke
Date:
Fri Mar 08 08:49:04 2013 +0000
Revision:
0:582e1b9c1cc1
Child:
1:6ff477690983
Initial version of library after converting Arduino library to mbed library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
SomeRandomBloke 0:582e1b9c1cc1 1 #include "mbed.h"
SomeRandomBloke 0:582e1b9c1cc1 2
SomeRandomBloke 0:582e1b9c1cc1 3 #include "Adafruit_WS2801.h"
SomeRandomBloke 0:582e1b9c1cc1 4
SomeRandomBloke 0:582e1b9c1cc1 5 // Example to control WS2801-based RGB LED Modules in a strand or strip
SomeRandomBloke 0:582e1b9c1cc1 6 // Written by Adafruit - MIT license
SomeRandomBloke 0:582e1b9c1cc1 7 /*****************************************************************************/
SomeRandomBloke 0:582e1b9c1cc1 8
SomeRandomBloke 0:582e1b9c1cc1 9 // Constructor for use with hardware SPI (specific clock/data pins):
SomeRandomBloke 0:582e1b9c1cc1 10 Adafruit_WS2801::Adafruit_WS2801(uint16_t n, uint8_t order): clkpin(PTD4), datapin(PTA12)
SomeRandomBloke 0:582e1b9c1cc1 11 {
SomeRandomBloke 0:582e1b9c1cc1 12 rgb_order = order;
SomeRandomBloke 0:582e1b9c1cc1 13 alloc(n);
SomeRandomBloke 0:582e1b9c1cc1 14 updatePins();
SomeRandomBloke 0:582e1b9c1cc1 15 }
SomeRandomBloke 0:582e1b9c1cc1 16
SomeRandomBloke 0:582e1b9c1cc1 17 // Constructor for use with arbitrary clock/data pins:
SomeRandomBloke 0:582e1b9c1cc1 18 Adafruit_WS2801::Adafruit_WS2801(uint16_t n, PinName dpin, PinName cpin, uint8_t order) : clkpin(cpin), datapin(dpin)
SomeRandomBloke 0:582e1b9c1cc1 19 {
SomeRandomBloke 0:582e1b9c1cc1 20 rgb_order = order;
SomeRandomBloke 0:582e1b9c1cc1 21 alloc(n);
SomeRandomBloke 0:582e1b9c1cc1 22
SomeRandomBloke 0:582e1b9c1cc1 23 // updatePins(dpin, cpin);
SomeRandomBloke 0:582e1b9c1cc1 24 }
SomeRandomBloke 0:582e1b9c1cc1 25
SomeRandomBloke 0:582e1b9c1cc1 26 // Constructor for use with a matrix configuration, specify w, h for size of matrix
SomeRandomBloke 0:582e1b9c1cc1 27 // assumes configuration where string starts at coordinate 0,0 and continues to w-1,0, w-1,1
SomeRandomBloke 0:582e1b9c1cc1 28 // and on to 0,1, 0,2 and on to w-1,2 and so on. Snaking back and forth till the end.
SomeRandomBloke 0:582e1b9c1cc1 29 // other function calls with provide access to pixels via an x,y coordinate system
SomeRandomBloke 0:582e1b9c1cc1 30 Adafruit_WS2801::Adafruit_WS2801(uint16_t w, uint16_t h, PinName dpin, PinName cpin, uint8_t order) : clkpin(cpin), datapin(dpin)
SomeRandomBloke 0:582e1b9c1cc1 31 {
SomeRandomBloke 0:582e1b9c1cc1 32 rgb_order = order;
SomeRandomBloke 0:582e1b9c1cc1 33 alloc(w * h);
SomeRandomBloke 0:582e1b9c1cc1 34 width = w;
SomeRandomBloke 0:582e1b9c1cc1 35 height = h;
SomeRandomBloke 0:582e1b9c1cc1 36 // updatePins(dpin, cpin);
SomeRandomBloke 0:582e1b9c1cc1 37 }
SomeRandomBloke 0:582e1b9c1cc1 38
SomeRandomBloke 0:582e1b9c1cc1 39 // Allocate 3 bytes per pixel, init to RGB 'off' state:
SomeRandomBloke 0:582e1b9c1cc1 40 void Adafruit_WS2801::alloc(uint16_t n)
SomeRandomBloke 0:582e1b9c1cc1 41 {
SomeRandomBloke 0:582e1b9c1cc1 42 begun = false;
SomeRandomBloke 0:582e1b9c1cc1 43 numLEDs = ((pixels = (uint8_t *)calloc(n, 3)) != NULL) ? n : 0;
SomeRandomBloke 0:582e1b9c1cc1 44
SomeRandomBloke 0:582e1b9c1cc1 45 for(int bits = 0; bits <= numLEDs*24; bits++) {
SomeRandomBloke 0:582e1b9c1cc1 46 clkpin = 0;
SomeRandomBloke 0:582e1b9c1cc1 47 datapin = 0;
SomeRandomBloke 0:582e1b9c1cc1 48 clkpin = 1;
SomeRandomBloke 0:582e1b9c1cc1 49 }
SomeRandomBloke 0:582e1b9c1cc1 50 clkpin = 0;
SomeRandomBloke 0:582e1b9c1cc1 51 }
SomeRandomBloke 0:582e1b9c1cc1 52
SomeRandomBloke 0:582e1b9c1cc1 53 // via Michael Vogt/neophob: empty constructor is used when strand length
SomeRandomBloke 0:582e1b9c1cc1 54 // isn't known at compile-time; situations where program config might be
SomeRandomBloke 0:582e1b9c1cc1 55 // read from internal flash memory or an SD card, or arrive via serial
SomeRandomBloke 0:582e1b9c1cc1 56 // command. If using this constructor, MUST follow up with updateLength()
SomeRandomBloke 0:582e1b9c1cc1 57 // and updatePins() to establish the strand length and output pins!
SomeRandomBloke 0:582e1b9c1cc1 58 // Also, updateOrder() to change RGB vs GRB order (RGB is default).
SomeRandomBloke 0:582e1b9c1cc1 59 Adafruit_WS2801::Adafruit_WS2801(void) : clkpin(PTD4), datapin(PTA12)
SomeRandomBloke 0:582e1b9c1cc1 60 {
SomeRandomBloke 0:582e1b9c1cc1 61 begun = false;
SomeRandomBloke 0:582e1b9c1cc1 62 numLEDs = 0;
SomeRandomBloke 0:582e1b9c1cc1 63 pixels = NULL;
SomeRandomBloke 0:582e1b9c1cc1 64 rgb_order = WS2801_RGB;
SomeRandomBloke 0:582e1b9c1cc1 65 updatePins(); // Must assume hardware SPI until pins are set
SomeRandomBloke 0:582e1b9c1cc1 66 }
SomeRandomBloke 0:582e1b9c1cc1 67
SomeRandomBloke 0:582e1b9c1cc1 68 // Release memory (as needed):
SomeRandomBloke 0:582e1b9c1cc1 69 Adafruit_WS2801::~Adafruit_WS2801(void)
SomeRandomBloke 0:582e1b9c1cc1 70 {
SomeRandomBloke 0:582e1b9c1cc1 71 if (pixels != NULL) {
SomeRandomBloke 0:582e1b9c1cc1 72 free(pixels);
SomeRandomBloke 0:582e1b9c1cc1 73 }
SomeRandomBloke 0:582e1b9c1cc1 74 }
SomeRandomBloke 0:582e1b9c1cc1 75
SomeRandomBloke 0:582e1b9c1cc1 76 // Activate hard/soft SPI as appropriate:
SomeRandomBloke 0:582e1b9c1cc1 77 void Adafruit_WS2801::begin(void)
SomeRandomBloke 0:582e1b9c1cc1 78 {
SomeRandomBloke 0:582e1b9c1cc1 79
SomeRandomBloke 0:582e1b9c1cc1 80 if(hardwareSPI == true) {
SomeRandomBloke 0:582e1b9c1cc1 81 startSPI();
SomeRandomBloke 0:582e1b9c1cc1 82 } else {
SomeRandomBloke 0:582e1b9c1cc1 83 // pinMode(datapin, OUTPUT);
SomeRandomBloke 0:582e1b9c1cc1 84 // pinMode(clkpin , OUTPUT);
SomeRandomBloke 0:582e1b9c1cc1 85 }
SomeRandomBloke 0:582e1b9c1cc1 86 begun = true;
SomeRandomBloke 0:582e1b9c1cc1 87 }
SomeRandomBloke 0:582e1b9c1cc1 88
SomeRandomBloke 0:582e1b9c1cc1 89 // Change pin assignments post-constructor, switching to hardware SPI:
SomeRandomBloke 0:582e1b9c1cc1 90 void Adafruit_WS2801::updatePins(void)
SomeRandomBloke 0:582e1b9c1cc1 91 {
SomeRandomBloke 0:582e1b9c1cc1 92 hardwareSPI = true;
SomeRandomBloke 0:582e1b9c1cc1 93 datapin = 0;
SomeRandomBloke 0:582e1b9c1cc1 94 clkpin = 0;
SomeRandomBloke 0:582e1b9c1cc1 95
SomeRandomBloke 0:582e1b9c1cc1 96 // If begin() was previously invoked, init the SPI hardware now:
SomeRandomBloke 0:582e1b9c1cc1 97 if(begun == true) startSPI();
SomeRandomBloke 0:582e1b9c1cc1 98 // Otherwise, SPI is NOT initted until begin() is explicitly called.
SomeRandomBloke 0:582e1b9c1cc1 99
SomeRandomBloke 0:582e1b9c1cc1 100 // Note: any prior clock/data pin directions are left as-is and are
SomeRandomBloke 0:582e1b9c1cc1 101 // NOT restored as inputs!
SomeRandomBloke 0:582e1b9c1cc1 102 }
SomeRandomBloke 0:582e1b9c1cc1 103
SomeRandomBloke 0:582e1b9c1cc1 104 // Change pin assignments post-constructor, using arbitrary pins:
SomeRandomBloke 0:582e1b9c1cc1 105 void Adafruit_WS2801::updatePins(PinName dpin, PinName cpin)
SomeRandomBloke 0:582e1b9c1cc1 106 {
SomeRandomBloke 0:582e1b9c1cc1 107
SomeRandomBloke 0:582e1b9c1cc1 108 if(begun == true) { // If begin() was previously invoked...
SomeRandomBloke 0:582e1b9c1cc1 109 // If previously using hardware SPI, turn that off:
SomeRandomBloke 0:582e1b9c1cc1 110 // if(hardwareSPI == true) SPI.end();
SomeRandomBloke 0:582e1b9c1cc1 111 // Regardless, now enable output on 'soft' SPI pins:
SomeRandomBloke 0:582e1b9c1cc1 112 // pinMode(dpin, OUTPUT);
SomeRandomBloke 0:582e1b9c1cc1 113 // pinMode(cpin, OUTPUT);
SomeRandomBloke 0:582e1b9c1cc1 114 } // Otherwise, pins are not set to outputs until begin() is called.
SomeRandomBloke 0:582e1b9c1cc1 115
SomeRandomBloke 0:582e1b9c1cc1 116 // Note: any prior clock/data pin directions are left as-is and are
SomeRandomBloke 0:582e1b9c1cc1 117 // NOT restored as inputs!
SomeRandomBloke 0:582e1b9c1cc1 118
SomeRandomBloke 0:582e1b9c1cc1 119 hardwareSPI = false;
SomeRandomBloke 0:582e1b9c1cc1 120 datapin = dpin;
SomeRandomBloke 0:582e1b9c1cc1 121 clkpin = cpin;
SomeRandomBloke 0:582e1b9c1cc1 122 // clkport = portOutputRegister(digitalPinToPort(cpin));
SomeRandomBloke 0:582e1b9c1cc1 123 // clkpinmask = digitalPinToBitMask(cpin);
SomeRandomBloke 0:582e1b9c1cc1 124 // dataport = portOutputRegister(digitalPinToPort(dpin));
SomeRandomBloke 0:582e1b9c1cc1 125 // datapinmask = digitalPinToBitMask(dpin);
SomeRandomBloke 0:582e1b9c1cc1 126 }
SomeRandomBloke 0:582e1b9c1cc1 127
SomeRandomBloke 0:582e1b9c1cc1 128 // Enable SPI hardware and set up protocol details:
SomeRandomBloke 0:582e1b9c1cc1 129 void Adafruit_WS2801::startSPI(void)
SomeRandomBloke 0:582e1b9c1cc1 130 {
SomeRandomBloke 0:582e1b9c1cc1 131 // SPI.begin();
SomeRandomBloke 0:582e1b9c1cc1 132 // SPI.setBitOrder(MSBFIRST);
SomeRandomBloke 0:582e1b9c1cc1 133 // SPI.setDataMode(SPI_MODE0);
SomeRandomBloke 0:582e1b9c1cc1 134 // SPI.setClockDivider(SPI_CLOCK_DIV16); // 1 MHz max, else flicker
SomeRandomBloke 0:582e1b9c1cc1 135 }
SomeRandomBloke 0:582e1b9c1cc1 136
SomeRandomBloke 0:582e1b9c1cc1 137 uint16_t Adafruit_WS2801::numPixels(void)
SomeRandomBloke 0:582e1b9c1cc1 138 {
SomeRandomBloke 0:582e1b9c1cc1 139 return numLEDs;
SomeRandomBloke 0:582e1b9c1cc1 140 }
SomeRandomBloke 0:582e1b9c1cc1 141
SomeRandomBloke 0:582e1b9c1cc1 142 // Change strand length (see notes with empty constructor, above):
SomeRandomBloke 0:582e1b9c1cc1 143 void Adafruit_WS2801::updateLength(uint16_t n)
SomeRandomBloke 0:582e1b9c1cc1 144 {
SomeRandomBloke 0:582e1b9c1cc1 145 if(pixels != NULL) free(pixels); // Free existing data (if any)
SomeRandomBloke 0:582e1b9c1cc1 146 // Allocate new data -- note: ALL PIXELS ARE CLEARED
SomeRandomBloke 0:582e1b9c1cc1 147 numLEDs = ((pixels = (uint8_t *)calloc(n, 3)) != NULL) ? n : 0;
SomeRandomBloke 0:582e1b9c1cc1 148 // 'begun' state does not change -- pins retain prior modes
SomeRandomBloke 0:582e1b9c1cc1 149 }
SomeRandomBloke 0:582e1b9c1cc1 150
SomeRandomBloke 0:582e1b9c1cc1 151 // Change RGB data order (see notes with empty constructor, above):
SomeRandomBloke 0:582e1b9c1cc1 152 void Adafruit_WS2801::updateOrder(uint8_t order)
SomeRandomBloke 0:582e1b9c1cc1 153 {
SomeRandomBloke 0:582e1b9c1cc1 154 rgb_order = order;
SomeRandomBloke 0:582e1b9c1cc1 155 // Existing LED data, if any, is NOT reformatted to new data order.
SomeRandomBloke 0:582e1b9c1cc1 156 // Calling function should clear or fill pixel data anew.
SomeRandomBloke 0:582e1b9c1cc1 157 }
SomeRandomBloke 0:582e1b9c1cc1 158
SomeRandomBloke 0:582e1b9c1cc1 159 void Adafruit_WS2801::show(void)
SomeRandomBloke 0:582e1b9c1cc1 160 {
SomeRandomBloke 0:582e1b9c1cc1 161 uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED
SomeRandomBloke 0:582e1b9c1cc1 162 uint8_t bit;
SomeRandomBloke 0:582e1b9c1cc1 163
SomeRandomBloke 0:582e1b9c1cc1 164 // Write 24 bits per pixel:
SomeRandomBloke 0:582e1b9c1cc1 165 // if(hardwareSPI) {
SomeRandomBloke 0:582e1b9c1cc1 166 // for(i=0; i<nl3; i++) {
SomeRandomBloke 0:582e1b9c1cc1 167 // SPDR = pixels[i];
SomeRandomBloke 0:582e1b9c1cc1 168 // while(!(SPSR & (1<<SPIF)));
SomeRandomBloke 0:582e1b9c1cc1 169 // }
SomeRandomBloke 0:582e1b9c1cc1 170 // } else {
SomeRandomBloke 0:582e1b9c1cc1 171
SomeRandomBloke 0:582e1b9c1cc1 172 /*
SomeRandomBloke 0:582e1b9c1cc1 173 for(int LED_number = 0 ; LED_number < _STRIP_LENGTH ; LED_number++) {
SomeRandomBloke 0:582e1b9c1cc1 174 if(_level != 100) {
SomeRandomBloke 0:582e1b9c1cc1 175 int R = ((strip_colors[LED_number] & 0x00ff0000) >> 16)*_level/100;
SomeRandomBloke 0:582e1b9c1cc1 176 int G = ((strip_colors[LED_number] & 0x0000ff00) >> 8)*_level/100;
SomeRandomBloke 0:582e1b9c1cc1 177 int B = (strip_colors[LED_number] & 0x000000ff)*_level/100;
SomeRandomBloke 0:582e1b9c1cc1 178 strip_colors_leveled[LED_number] = (R << 16)|(G << 8)|B;
SomeRandomBloke 0:582e1b9c1cc1 179 } else strip_colors_leveled[LED_number] = strip_colors[LED_number];
SomeRandomBloke 0:582e1b9c1cc1 180 int this_led_color = strip_colors_leveled[LED_number]; //24 bits of color data
SomeRandomBloke 0:582e1b9c1cc1 181 for(char color_bit = 23 ; color_bit != 255 ; color_bit--) {
SomeRandomBloke 0:582e1b9c1cc1 182 _CKI = 0;
SomeRandomBloke 0:582e1b9c1cc1 183 mask = 1 << color_bit;
SomeRandomBloke 0:582e1b9c1cc1 184 if(this_led_color & mask)_SDI = 1;
SomeRandomBloke 0:582e1b9c1cc1 185 else _SDI = 0;
SomeRandomBloke 0:582e1b9c1cc1 186 _CKI = 1; //Data is latched when clock goes high
SomeRandomBloke 0:582e1b9c1cc1 187 }
SomeRandomBloke 0:582e1b9c1cc1 188 }
SomeRandomBloke 0:582e1b9c1cc1 189 _CKI = 0;
SomeRandomBloke 0:582e1b9c1cc1 190 wait_us(_reset_delay); //Wait for 1ms to go into reset
SomeRandomBloke 0:582e1b9c1cc1 191 */
SomeRandomBloke 0:582e1b9c1cc1 192 for(i=0; i<nl3; i++ ) {
SomeRandomBloke 0:582e1b9c1cc1 193 for(bit=0x80; bit; bit >>= 1) {
SomeRandomBloke 0:582e1b9c1cc1 194 clkpin = 0;
SomeRandomBloke 0:582e1b9c1cc1 195 if(pixels[i] & bit) datapin = 1;
SomeRandomBloke 0:582e1b9c1cc1 196 else datapin = 0;
SomeRandomBloke 0:582e1b9c1cc1 197 clkpin = 1;
SomeRandomBloke 0:582e1b9c1cc1 198 }
SomeRandomBloke 0:582e1b9c1cc1 199 }
SomeRandomBloke 0:582e1b9c1cc1 200 // }
SomeRandomBloke 0:582e1b9c1cc1 201
SomeRandomBloke 0:582e1b9c1cc1 202 wait_ms(1); // Data is latched by holding clock pin low for 1 millisecond
SomeRandomBloke 0:582e1b9c1cc1 203 }
SomeRandomBloke 0:582e1b9c1cc1 204
SomeRandomBloke 0:582e1b9c1cc1 205 // Set pixel color from separate 8-bit R, G, B components:
SomeRandomBloke 0:582e1b9c1cc1 206 void Adafruit_WS2801::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
SomeRandomBloke 0:582e1b9c1cc1 207 {
SomeRandomBloke 0:582e1b9c1cc1 208 if(n < numLEDs) { // Arrays are 0-indexed, thus NOT '<='
SomeRandomBloke 0:582e1b9c1cc1 209 uint8_t *p = &pixels[n * 3];
SomeRandomBloke 0:582e1b9c1cc1 210 // See notes later regarding color order
SomeRandomBloke 0:582e1b9c1cc1 211 if(rgb_order == WS2801_RGB) {
SomeRandomBloke 0:582e1b9c1cc1 212 *p++ = r;
SomeRandomBloke 0:582e1b9c1cc1 213 *p++ = g;
SomeRandomBloke 0:582e1b9c1cc1 214 } else {
SomeRandomBloke 0:582e1b9c1cc1 215 *p++ = g;
SomeRandomBloke 0:582e1b9c1cc1 216 *p++ = r;
SomeRandomBloke 0:582e1b9c1cc1 217 }
SomeRandomBloke 0:582e1b9c1cc1 218 *p++ = b;
SomeRandomBloke 0:582e1b9c1cc1 219 }
SomeRandomBloke 0:582e1b9c1cc1 220 }
SomeRandomBloke 0:582e1b9c1cc1 221
SomeRandomBloke 0:582e1b9c1cc1 222 // Set pixel color from separate 8-bit R, G, B components using x,y coordinate system:
SomeRandomBloke 0:582e1b9c1cc1 223 void Adafruit_WS2801::setPixelColor(uint16_t x, uint16_t y, uint8_t r, uint8_t g, uint8_t b)
SomeRandomBloke 0:582e1b9c1cc1 224 {
SomeRandomBloke 0:582e1b9c1cc1 225 bool evenRow = ((y % 2) == 0);
SomeRandomBloke 0:582e1b9c1cc1 226 // calculate x offset first
SomeRandomBloke 0:582e1b9c1cc1 227 uint16_t offset = x % width;
SomeRandomBloke 0:582e1b9c1cc1 228 if (!evenRow) {
SomeRandomBloke 0:582e1b9c1cc1 229 offset = (width-1) - offset;
SomeRandomBloke 0:582e1b9c1cc1 230 }
SomeRandomBloke 0:582e1b9c1cc1 231 // add y offset
SomeRandomBloke 0:582e1b9c1cc1 232 offset += y * width;
SomeRandomBloke 0:582e1b9c1cc1 233 setPixelColor(offset, r, g, b);
SomeRandomBloke 0:582e1b9c1cc1 234 }
SomeRandomBloke 0:582e1b9c1cc1 235
SomeRandomBloke 0:582e1b9c1cc1 236 // Set pixel color from 'packed' 32-bit RGB value:
SomeRandomBloke 0:582e1b9c1cc1 237 void Adafruit_WS2801::setPixelColor(uint16_t n, uint32_t c)
SomeRandomBloke 0:582e1b9c1cc1 238 {
SomeRandomBloke 0:582e1b9c1cc1 239 if(n < numLEDs) { // Arrays are 0-indexed, thus NOT '<='
SomeRandomBloke 0:582e1b9c1cc1 240 uint8_t *p = &pixels[n * 3];
SomeRandomBloke 0:582e1b9c1cc1 241 // To keep the show() loop as simple & fast as possible, the
SomeRandomBloke 0:582e1b9c1cc1 242 // internal color representation is native to different pixel
SomeRandomBloke 0:582e1b9c1cc1 243 // types. For compatibility with existing code, 'packed' RGB
SomeRandomBloke 0:582e1b9c1cc1 244 // values passed in or out are always 0xRRGGBB order.
SomeRandomBloke 0:582e1b9c1cc1 245 if(rgb_order == WS2801_RGB) {
SomeRandomBloke 0:582e1b9c1cc1 246 *p++ = c >> 16; // Red
SomeRandomBloke 0:582e1b9c1cc1 247 *p++ = c >> 8; // Green
SomeRandomBloke 0:582e1b9c1cc1 248 } else {
SomeRandomBloke 0:582e1b9c1cc1 249 *p++ = c >> 8; // Green
SomeRandomBloke 0:582e1b9c1cc1 250 *p++ = c >> 16; // Red
SomeRandomBloke 0:582e1b9c1cc1 251 }
SomeRandomBloke 0:582e1b9c1cc1 252 *p++ = c; // Blue
SomeRandomBloke 0:582e1b9c1cc1 253 }
SomeRandomBloke 0:582e1b9c1cc1 254 }
SomeRandomBloke 0:582e1b9c1cc1 255
SomeRandomBloke 0:582e1b9c1cc1 256 // Set pixel color from 'packed' 32-bit RGB value using x,y coordinate system:
SomeRandomBloke 0:582e1b9c1cc1 257 void Adafruit_WS2801::setPixelColor(uint16_t x, uint16_t y, uint32_t c)
SomeRandomBloke 0:582e1b9c1cc1 258 {
SomeRandomBloke 0:582e1b9c1cc1 259 bool evenRow = ((y % 2) == 0);
SomeRandomBloke 0:582e1b9c1cc1 260 // calculate x offset first
SomeRandomBloke 0:582e1b9c1cc1 261 uint16_t offset = x % width;
SomeRandomBloke 0:582e1b9c1cc1 262 if (!evenRow) {
SomeRandomBloke 0:582e1b9c1cc1 263 offset = (width-1) - offset;
SomeRandomBloke 0:582e1b9c1cc1 264 }
SomeRandomBloke 0:582e1b9c1cc1 265 // add y offset
SomeRandomBloke 0:582e1b9c1cc1 266 offset += y * width;
SomeRandomBloke 0:582e1b9c1cc1 267 setPixelColor(offset, c);
SomeRandomBloke 0:582e1b9c1cc1 268 }
SomeRandomBloke 0:582e1b9c1cc1 269
SomeRandomBloke 0:582e1b9c1cc1 270 // Query color from previously-set pixel (returns packed 32-bit RGB value)
SomeRandomBloke 0:582e1b9c1cc1 271 uint32_t Adafruit_WS2801::getPixelColor(uint16_t n)
SomeRandomBloke 0:582e1b9c1cc1 272 {
SomeRandomBloke 0:582e1b9c1cc1 273 if(n < numLEDs) {
SomeRandomBloke 0:582e1b9c1cc1 274 uint16_t ofs = n * 3;
SomeRandomBloke 0:582e1b9c1cc1 275 // To keep the show() loop as simple & fast as possible, the
SomeRandomBloke 0:582e1b9c1cc1 276 // internal color representation is native to different pixel
SomeRandomBloke 0:582e1b9c1cc1 277 // types. For compatibility with existing code, 'packed' RGB
SomeRandomBloke 0:582e1b9c1cc1 278 // values passed in or out are always 0xRRGGBB order.
SomeRandomBloke 0:582e1b9c1cc1 279 return (rgb_order == WS2801_RGB) ?
SomeRandomBloke 0:582e1b9c1cc1 280 ((uint32_t)pixels[ofs] << 16) | ((uint16_t) pixels[ofs + 1] << 8) | pixels[ofs + 2] :
SomeRandomBloke 0:582e1b9c1cc1 281 (pixels[ofs] << 8) | ((uint32_t)pixels[ofs + 1] << 16) | pixels[ofs + 2];
SomeRandomBloke 0:582e1b9c1cc1 282 }
SomeRandomBloke 0:582e1b9c1cc1 283
SomeRandomBloke 0:582e1b9c1cc1 284 return 0; // Pixel # is out of bounds
SomeRandomBloke 0:582e1b9c1cc1 285 }