File content as of revision 2:51722225d46c:

/*------------------------------------------------------------------------
  Arduino library to control Adafruit Dot Star addressable RGB LEDs.

  Written by Limor Fried and Phil Burgess for Adafruit Industries.

  Adafruit invests time and resources providing this open source code,
  please support Adafruit and open-source hardware by purchasing products
  from Adafruit!

  ------------------------------------------------------------------------
  This file is part of the Adafruit Dot Star library.

  Adafruit Dot Star is free software: you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public License
  as published by the Free Software Foundation, either version 3 of
  the License, or (at your option) any later version.

  Adafruit Dot Star is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with DotStar.  If not, see <http://www.gnu.org/licenses/>.
  ------------------------------------------------------------------------*/

#include "mbed.h"
#include "DotStar.h"

// Constructor for hardware SPI -- must connect to MOSI, SCK pins
Adafruit_DotStar::Adafruit_DotStar(uint16_t n, PinName miso, PinName mosi, PinName sclk, int hz, uint8_t o)
: numLEDs(n)
, dataPin(USE_HW_SPI)
, clockPin(USE_HW_SPI)
, spi(NULL)
, miso_(miso)
, mosi_(mosi)
, sclk_(sclk)
, data_out(NULL)
, sclk_out(NULL)
, port(Port0)
, port_out(NULL)
, d_mask(0)
, c_mask(0)
, b_use_port(false)
, brightness(0)
, pixels(NULL)
, rOffset(o & 3)
, gOffset((o >> 2) & 3)
, bOffset((o >> 4) & 3)
{
    updateLength(n);
}

// Constructor for 'soft' (bitbang) SPI -- any two pins can be used
Adafruit_DotStar::Adafruit_DotStar(uint16_t n, PinName data, PinName clock, uint8_t o)
: dataPin(data)
, clockPin(clock)
, spi(NULL)
, miso_(NC)
, mosi_(NC)
, sclk_(NC)
, data_out(NULL)
, sclk_out(NULL)
, port(Port0)
, port_out(NULL)
, d_mask(0)
, c_mask(0)
, b_use_port(false)
, brightness(0)
, pixels(NULL)
, rOffset(o & 3)
, gOffset((o >> 2) & 3)
, bOffset((o >> 4) & 3)
{
    updateLength(n);
}

// Constructor for 'soft' (bitbang) SPI -- any two pins can be used
Adafruit_DotStar::Adafruit_DotStar(uint16_t n, PortName p, int dmask, int cmask, uint8_t o)
: dataPin(NC)
, clockPin(NC)
, spi(NULL)
, miso_(NC)
, mosi_(NC)
, sclk_(NC)
, data_out(NULL)
, sclk_out(NULL)
, port(p)
, port_out(NULL)
, d_mask(dmask)
, c_mask(cmask)
, b_use_port(true)
, brightness(0)
, pixels(NULL)
, rOffset(o & 3)
, gOffset((o >> 2) & 3)
, bOffset((o >> 4) & 3)
{
    updateLength(n);
}

Adafruit_DotStar::~Adafruit_DotStar(void) { // Destructor
    if(pixels)                free(pixels);
    if(dataPin == USE_HW_SPI) hw_spi_end();
    else                      sw_spi_end();
}

void Adafruit_DotStar::begin(void) { // Initialize SPI
    if(dataPin == USE_HW_SPI) hw_spi_init();
    else                      sw_spi_init();
}

// Change to hardware SPI -- must connect to MOSI, SCK pins
void Adafruit_DotStar::updatePins(void) {
    sw_spi_end();
    dataPin = USE_HW_SPI;
    hw_spi_init();
}

// Change to 'soft' (bitbang) SPI -- any two pins can be used
void Adafruit_DotStar::updatePins(PinName data, PinName clock) {
    hw_spi_end();
    dataPin  = data;
    clockPin = clock;
    sw_spi_init();
}

// Length can be changed post-constructor for similar reasons (sketch
// config not hardcoded).  But DON'T use this for "recycling" strip RAM...
// all that reallocation is likely to fragment and eventually fail.
// Instead, set length once to longest strip.
void Adafruit_DotStar::updateLength(uint16_t n) {
    if(pixels) free(pixels);
    uint16_t bytes = (rOffset == gOffset) ?
        n + ((n + 3) / 4) : // MONO: 10 bits/pixel, round up to next byte
        n * 3;              // COLOR: 3 bytes/pixel
    if((pixels = (uint8_t *)malloc(bytes))) {
        numLEDs = n;
        clear();
    } else {
        numLEDs = 0;
    }
}

// SPI STUFF ---------------------------------------------------------------

void Adafruit_DotStar::hw_spi_init(void) { // Initialize hardware SPI
    spi = new SPI(mosi_, miso_, sclk_); // mosi, miso, sclk
    spi->format(8, 0);   // 8bit, mode:0
    spi->frequency(8000000); // Hz
}

void Adafruit_DotStar::hw_spi_end(void) { // Stop hardware SPI
    if (spi) delete spi;
}

void Adafruit_DotStar::sw_spi_init(void) { // Init 'soft' (bitbang) SPI
    if (b_use_port) {
        port_out = new PortOut(port, (d_mask | c_mask));
    } else {
        data_out = new DigitalOut(dataPin);
        sclk_out = new DigitalOut(clockPin);
    }
}

void Adafruit_DotStar::sw_spi_end() { // Stop 'soft' SPI
    if (port_out) delete(port_out);
    if (data_out) delete(data_out);
    if (sclk_out) delete(sclk_out);
}

//inline void Adafruit_DotStar::sw_spi_out(uint8_t n) { // Bitbang SPI write
//    if (b_use_port) {
//        for(uint8_t i=8; i--; n <<= 1) {
//            int mask = (n & 0x80) ? (d_mask | c_mask) : c_mask;
//            *port_out = mask;
//            *port_out = (mask & ~c_mask);
//        }
//    } else {
//        for(uint8_t i=8; i--; n <<= 1) {
//            if(n & 0x80) *data_out = 1;
//            else         *data_out = 0;
//            *sclk_out = 1;
//            *sclk_out = 0;
//        }
//    }
//}

/* ISSUE DATA TO LED STRIP -------------------------------------------------

  Although the LED driver has an additional per-pixel 5-bit brightness
  setting, it is NOT used or supported here because it's a brain-dead
  misfeature that's counter to the whole point of Dot Stars, which is to
  have a much faster PWM rate than NeoPixels.  It gates the high-speed
  PWM output through a second, much slower PWM (about 400 Hz), rendering
  it useless for POV.  This brings NOTHING to the table that can't be
  already handled better in one's sketch code.  If you really can't live
  without this abomination, you can fork the library and add it for your
  own use, but any pull requests for this will NOT be merged, nuh uh!
*/

//inline void Adafruit_DotStar::show() {
//  if(!pixels) return;
//
//    uint8_t *ptr = pixels;            // -> LED data
//    uint16_t n   = numLEDs;              // Counter
//    uint16_t b16 = (uint16_t)brightness; // Type-convert for fixed-point math
//
//    if(dataPin == USE_HW_SPI) {
//      
//      for(size_t i=0; i<4; i++) spi->write(0x00);    // 4 byte start-frame marker
//      if(brightness) {                     // Scale pixel brightness on output
//        for (size_t i=n; i>0; i--) {
//            spi->write(0xFF);                   //  Pixel start
//            for(size_t j=0; j<3; j++) spi->write((*ptr++ * b16) >> 8); // Scale, write RGB
//        }
//      } else {                             // Full brightness (no scaling)
//        for (size_t i=n; i>0; i--) {
//            spi->write(0xFF);                   //  Pixel start
//            for(size_t j=0; j<3; j++) spi->write(*ptr++); // Write R,G,B
//        }
//      }
//      // Four end-frame bytes are seemingly indistinguishable from a white
//      // pixel, and empirical testing suggests it can be left out...but it's
//      // always a good idea to follow the datasheet, in case future hardware
//      // revisions are more strict (e.g. might mandate use of end-frame
//      // before start-frame marker).  i.e. let's not remove this.
//      for(size_t i=0; i<4; i++) spi->write(0xFF);
//
//  } else {                               // Soft (bitbang) SPI
//
//    for(size_t i=0; i<4; i++) sw_spi_out(0);    // Start-frame marker
//    if(brightness) {                     // Scale pixel brightness on output
//      do {                               // For each pixel...
//        sw_spi_out(0xFF);                //  Pixel start
//        for(size_t i=0; i<3; i++) sw_spi_out((*ptr++ * b16) >> 8); // Scale, write
//      } while(--n);
//    } else {                             // Full brightness (no scaling)
//      do {                               // For each pixel...
//        sw_spi_out(0xFF);                //  Pixel start
//        for(size_t i=0; i<3; i++) sw_spi_out(*ptr++); // R,G,B
//      } while(--n);
//    }
//    for(size_t i=0; i<4; i++) sw_spi_out(0xFF); // End-frame marker (see note above)
//  }
//}

inline void Adafruit_DotStar::clear() { // Write 0s (off) to full pixel buffer
    memset(pixels, 0, (rOffset == gOffset) ?
        numLEDs + ((numLEDs + 3) / 4) : // MONO: 10 bits/pixel
        numLEDs * 3);                   // COLOR: 3 bytes/pixel
}

// Set pixel color, separate R,G,B values (0-255 ea.)
//inline void Adafruit_DotStar::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
//{
//  if(n < numLEDs) {
//    uint8_t *p = &pixels[n * 3];
//    p[rOffset] = r;
//    p[gOffset] = g;
//    p[bOffset] = b;
//  }
//}

// Set pixel color, 'packed' RGB value (0x000000 - 0xFFFFFF)
inline void Adafruit_DotStar::setPixelColor(uint16_t n, uint32_t c) {
    if(n < numLEDs) {
        uint8_t *p = &pixels[n * 3];
        p[rOffset] = (uint8_t)(c >> 16);
        p[gOffset] = (uint8_t)(c >>  8);
        p[bOffset] = (uint8_t)c;
    }
}

// Convert separate R,G,B to packed value
inline uint32_t Adafruit_DotStar::Color(uint8_t r, uint8_t g, uint8_t b) {
    return ((uint32_t)r << 16) | ((uint32_t)g << 8) | b;
}

// Read color from previously-set pixel, returns packed RGB value.
inline uint32_t Adafruit_DotStar::getPixelColor(uint16_t n) const {
    if(n >= numLEDs) return 0;
    uint8_t *p = &pixels[n * 3];
    return ((uint32_t)p[rOffset] << 16) |
           ((uint32_t)p[gOffset] <<  8) |
            (uint32_t)p[bOffset];
}

inline uint16_t Adafruit_DotStar::numPixels(void) { // Ret. strip length
    return numLEDs;
}

// Set global strip brightness.  This does not have an immediate effect;
// must be followed by a call to show().  Not a fan of this...for various
// reasons I think it's better handled in one's sketch, but it's here for
// parity with the NeoPixel library.  Good news is that brightness setting
// in this library is 'non destructive' -- it's applied as color data is
// being issued to the strip, not during setPixel(), and also means that
// getPixelColor() returns the exact value originally stored.
inline void Adafruit_DotStar::setBrightness(uint8_t b) {
    // Stored brightness value is different than what's passed.  This
    // optimizes the actual scaling math later, allowing a fast 8x8-bit
    // multiply and taking the MSB.  'brightness' is a uint8_t, adding 1
    // here may (intentionally) roll over...so 0 = max brightness (color
    // values are interpreted literally; no scaling), 1 = min brightness
    // (off), 255 = just below max brightness.
    brightness = b + 1;
}

inline uint8_t Adafruit_DotStar::getBrightness(void) const {
    return brightness - 1; // Reverse above operation
}

// Return pointer to the library's pixel data buffer.  Use carefully,
// much opportunity for mayhem.  It's mostly for code that needs fast
// transfers, e.g. SD card to LEDs.  Color data is in BGR order.
inline uint8_t *Adafruit_DotStar::getPixels(void) const {
    return pixels;
}