File content as of revision 2:2fdaa13896a4:

#include "mbed.h"
#include "Adafruit_WS2801.h"

// Example to control WS2801-based RGB LED Modules in a strand or strip
// Written by Adafruit - MIT license
/*****************************************************************************/

SPI spi(p16, p15, p13); // mosi, miso, sclk

// Constructor for use with hardware SPI (specific clock/data pins):
//Adafruit_WS2801::Adafruit_WS2801(uint16_t n, uint8_t order): clkpin(PTD4), datapin(PTA12)
//{
//    rgb_order = order;
//    alloc(n);
//    updatePins();
//}

// Constructor for use with arbitrary clock/data pins:
Adafruit_WS2801::Adafruit_WS2801(uint16_t n, PinName dpin, PinName cpin, uint8_t order)  : clkpin(cpin), datapin(dpin)
{
    rgb_order = order;
    alloc(n);
   
//  updatePins(dpin, cpin);
}

// Constructor for use with a matrix configuration, specify w, h for size of matrix
// assumes configuration where string starts at coordinate 0,0 and continues to w-1,0, w-1,1
// and on to 0,1, 0,2 and on to w-1,2 and so on. Snaking back and forth till the end.
// other function calls with provide access to pixels via an x,y coordinate system
Adafruit_WS2801::Adafruit_WS2801(uint16_t w, uint16_t h, PinName dpin, PinName cpin, uint8_t order)  : clkpin(cpin), datapin(dpin)
{
    rgb_order = order;
    alloc(w * h);
    width = w;
    height = h;
//  updatePins(dpin, cpin);
}

// Allocate 3 bytes per pixel, init to RGB 'off' state:
void Adafruit_WS2801::alloc(uint16_t n)
{
    begun   = false;
    numLEDs = ((pixels = (uint8_t *)calloc(n, 3)) != NULL) ? n : 0;


//    for(int bits = 0; bits <= numLEDs*24; bits++) {
//        spi.write(0x00);
//        clkpin = 0;
//        datapin = 0;
//        clkpin = 1;
//    }
//    clkpin = 0;
}

// via Michael Vogt/neophob: empty constructor is used when strand length
// isn't known at compile-time; situations where program config might be
// read from internal flash memory or an SD card, or arrive via serial
// command.  If using this constructor, MUST follow up with updateLength()
// and updatePins() to establish the strand length and output pins!
// Also, updateOrder() to change RGB vs GRB order (RGB is default).
//Adafruit_WS2801::Adafruit_WS2801(void) : clkpin(PTD4), datapin(PTA12)
//{
//    begun     = false;
//    numLEDs   = 0;
//    pixels    = NULL;
//    rgb_order = WS2801_RGB;
//    updatePins(); // Must assume hardware SPI until pins are set
//}

// Release memory (as needed):
Adafruit_WS2801::~Adafruit_WS2801(void)
{
    if (pixels != NULL) {
        free(pixels);
    }
}

// Activate hard/soft SPI as appropriate:
void Adafruit_WS2801::begin(void)
{
    if( hardwareSPI ) {
        // Setup the spi for 8 bit data, high steady state clock,
        // second edge capture, with a 1MHz clock rate
        spi.format(8,0);
        spi.frequency(1000000);
    } else {
        datapin = 0;
        clkpin = 0;
    }
    begun = true;
}

// Change pin assignments post-constructor, switching to hardware SPI:
void Adafruit_WS2801::updatePins(void)
{
    hardwareSPI = true;
    datapin = 0;
    clkpin = 0;
}


// Change pin assignments post-constructor, using arbitrary pins:
//void Adafruit_WS2801::updatePins(PinName dpin, PinName cpin)
//{
    // Note: any prior clock/data pin directions are left as-is and are
    // NOT restored as inputs!

//    datapin     = DigitalOut(dpin);
//    clkpin      = DigitalOut(cpin);
//}

uint16_t Adafruit_WS2801::numPixels(void)
{
    return numLEDs;
}

// Change strand length (see notes with empty constructor, above):
void Adafruit_WS2801::updateLength(uint16_t n)
{
    if(pixels != NULL) free(pixels); // Free existing data (if any)
    // Allocate new data -- note: ALL PIXELS ARE CLEARED
    numLEDs = ((pixels = (uint8_t *)calloc(n, 3)) != NULL) ? n : 0;
    // 'begun' state does not change -- pins retain prior modes
}

// Change RGB data order (see notes with empty constructor, above):
void Adafruit_WS2801::updateOrder(uint8_t order)
{
    rgb_order = order;
    // Existing LED data, if any, is NOT reformatted to new data order.
    // Calling function should clear or fill pixel data anew.
}

void Adafruit_WS2801::show(void)
{
    uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED

    if( hardwareSPI ) {
        for(i=0; i<nl3; i++ ) {
            spi.write( pixels[i]);
        }        
        wait_ms(1); // Data is latched by holding clock pin low for 1 millisecond
    } else {
        uint8_t  bit;

        // Write 24 bits per pixel:
        for(i=0; i<nl3; i++ ) {
            for(bit=0x80; bit; bit >>= 1) {
                clkpin = 0;
                datapin = (pixels[i] & bit) ? 1 : 0;
                clkpin = 1;
                wait_us(100);
            }
        }
        datapin = 0;

        clkpin = 0;
        wait_ms(1); // Data is latched by holding clock pin low for 1 millisecond
        clkpin = 1;
    }
}

// Set pixel color from separate 8-bit R, G, B components:
void Adafruit_WS2801::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
{
    if(n < numLEDs) { // Arrays are 0-indexed, thus NOT '<='
        uint8_t *p = &pixels[n * 3];
        // See notes later regarding color order
        if(rgb_order == WS2801_RGB) {
            *p++ = r;
            *p++ = g;
        } else {
            *p++ = g;
            *p++ = r;
        }
        *p++ = b;
    }
}

// Set pixel color from separate 8-bit R, G, B components using x,y coordinate system:
void Adafruit_WS2801::setPixelColor(uint16_t x, uint16_t y, uint8_t r, uint8_t g, uint8_t b)
{
    bool evenRow = ((y % 2) == 0);
    // calculate x offset first
    uint16_t offset = x % width;
    if (!evenRow) {
        offset = (width-1) - offset;
    }
    // add y offset
    offset += y * width;
    setPixelColor(offset, r, g, b);
}

// Set pixel color from 'packed' 32-bit RGB value:
void Adafruit_WS2801::setPixelColor(uint16_t n, uint32_t c)
{
    if(n < numLEDs) { // Arrays are 0-indexed, thus NOT '<='
        uint8_t *p = &pixels[n * 3];
        // To keep the show() loop as simple & fast as possible, the
        // internal color representation is native to different pixel
        // types.  For compatibility with existing code, 'packed' RGB
        // values passed in or out are always 0xRRGGBB order.
        if(rgb_order == WS2801_RGB) {
            *p++ = c >> 16; // Red
            *p++ = c >>  8; // Green
        } else {
            *p++ = c >>  8; // Green
            *p++ = c >> 16; // Red
        }
        *p++ = c;         // Blue
    }
}

// Set pixel color from 'packed' 32-bit RGB value using x,y coordinate system:
void Adafruit_WS2801::setPixelColor(uint16_t x, uint16_t y, uint32_t c)
{
    bool evenRow = ((y % 2) == 0);
    // calculate x offset first
    uint16_t offset = x % width;
    if (!evenRow) {
        offset = (width-1) - offset;
    }
    // add y offset
    offset += y * width;
    setPixelColor(offset, c);
}

// Query color from previously-set pixel (returns packed 32-bit RGB value)
uint32_t Adafruit_WS2801::getPixelColor(uint16_t n)
{
    if(n < numLEDs) {
        uint16_t ofs = n * 3;
        // To keep the show() loop as simple & fast as possible, the
        // internal color representation is native to different pixel
        // types.  For compatibility with existing code, 'packed' RGB
        // values passed in or out are always 0xRRGGBB order.
        return (rgb_order == WS2801_RGB) ?
               ((uint32_t)pixels[ofs] << 16) | ((uint16_t) pixels[ofs + 1] <<  8) | pixels[ofs + 2] :
               (pixels[ofs] <<  8) | ((uint32_t)pixels[ofs + 1] << 16) | pixels[ofs + 2];
    }

    return 0; // Pixel # is out of bounds
}