File content as of revision 7:ee356aa4c22d:

// 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>
// Then remonstered to use hardware SPI for blast mode.
//
/*****************************************************************************/

#include "LedStrip.h"
#include "LPD8806_fast.h"
#include "board_variant.h"

#ifdef PIXELPUSHER_3

#include "MODDMA.h"

#define LATCHNUMBER 32

// DMA controller and frequency setting
extern MODDMA dma;
extern int turbo_mode;

/*
    PixelPusher 3 pin names:

    STRIP1C = P2_9,
    STRIP1D = P4_29,
    STRIP2C = P0_18,
    STRIP2D = P2_1,
    STRIP3C = P2_6,
    STRIP3D = P0_8,
    STRIP4C = P2_8,
    STRIP4D = P0_7,
    STRIP5C = P0_15,
    STRIP5D = P2_0,
    STRIP6C = P0_17,
    STRIP6D = P2_4,
    STRIP7C = P2_5,
    STRIP7D = P0_9,
    STRIP8C = P2_7,
    STRIP8D = P0_6,
    
*/

/*
 *  STRIP7D is P0[9] which is SSP1 MOSI
 *  STRIP4D is P0[7] which is SSP1 SCK
 *
 *  STRIP2C is P0[18] which is SSP0 MOSI
 *  STRIP5C is P0[15] which is SSP0 SCK
 */ 
 
 // when the transfer is complete, kill the channel.
 void dma_complete_callback() {
    MODDMA_Config *config = dma.getConfig();
    dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
    
    // clear the IRQ flags
    if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq();    
    if (dma.irqType() == MODDMA::ErrIrq) dma.clearErrIrq();  
 }
 
 void dma_err_callback() {
    MODDMA_Config *config = dma.getConfig();
    dma.Disable( (MODDMA::CHANNELS)config->channelNum() );
    
    // clear the IRQ flags
    if (dma.irqType() == MODDMA::TcIrq) dma.clearTcIrq();    
    if (dma.irqType() == MODDMA::ErrIrq) dma.clearErrIrq();  
 } 
 
LPD8806_fast::LPD8806_fast(PinName dataPin, PinName clockPin, int n) :
    _spi(dataPin, NC, clockPin)
 {
    // Allocate 3 bytes per pixel:
    numLEDs = n;
    pixels = (uint8_t *)malloc(numLEDs * 3 + ((numLEDs + LATCHNUMBER-1) / LATCHNUMBER));
    if (pixels) {
        memset(pixels, 0x80, numLEDs * 3); // Init to RGB 'off' state
        memset(pixels+numLEDs*3, 0x0, (numLEDs + LATCHNUMBER-1) / LATCHNUMBER); // latch data
    }
        
    _spi.format(8,0);
    _spi.frequency(turbo_mode*1000000);
    
    // we are strip 2
    if (dataPin == STRIP2C) {
        strip_num = 2;
    } else {
        strip_num = 1;
    }
    dma_config = new MODDMA_Config;
}
 
inline void LPD8806_fast::write(uint8_t byte) {
    _spi.write(byte);
}

/*
inline void LPD8806_fast::write(uint8_t byte) {
    for (int i=0; i<8; i++) {
        clk = 0;
        dat = (byte & 0x80);
        clk = 1;
        byte <<= 1;
    }
    clk = 0;
}*/

void LPD8806_fast::begin(void) {

    blank();
    show();
    show();
}

uint16_t LPD8806_fast::numPixels(void) {
    return numLEDs;
}

void LPD8806_fast::blank(void) {
    memset(pixels, 0x80, 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 LPD8806_fast::show(void) {
     if (strip_num == 2) {
        dma_config  -> channelNum   (MODDMA::Channel_0)
                    -> srcMemAddr   ( (uint32_t) pixels )
                    -> dstMemAddr   ( MODDMA::SSP0_Tx )
                    -> transferSize (numLEDs * 3 + ((numLEDs + LATCHNUMBER-1) / LATCHNUMBER))
                    -> transferType (MODDMA::m2p)
                    -> dstConn      (MODDMA::SSP0_Tx)
                    -> attach_tc    (&dma_complete_callback)
                    -> attach_err   (&dma_err_callback);
       LPC_SSP0->DMACR = (1<<1)|(1<<0); // TX,RXDMAE
    } else {
        dma_config  -> channelNum   (MODDMA::Channel_1)
                    -> srcMemAddr   ( (uint32_t) pixels )
                    -> dstMemAddr   ( MODDMA::SSP1_Tx )
                    -> transferSize (numLEDs * 3 + ((numLEDs +LATCHNUMBER-1) / LATCHNUMBER))
                    -> transferType (MODDMA::m2p)
                    -> dstConn      (MODDMA::SSP1_Tx)
                    -> attach_tc    (&dma_complete_callback)
                    -> attach_err   (&dma_err_callback);
       LPC_SSP1->DMACR = (1<<1)|(1<<0); // TX,RXDMAE
    }
    while (dma.Enabled(dma_config->channelNum())) {
        __nop();
    }
    dma.Setup(dma_config);
    dma.Enable(dma_config);
}

// LPD8806 is 7-bit, so we shift to normalize to 256 PWM steps.
uint32_t LPD8806_fast::total_luminance(void) {
    uint32_t running_total;
    running_total = 0;
    for (int i=0; i<numLEDs*3; i++)
        running_total += ((pixels[i] & 0x7f) <<1);
    return running_total;
}

// Convert R,G,B to combined 32-bit color
uint32_t LPD8806_fast::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 0x808080 | ((uint32_t)(g>>1) << 16) | ((uint32_t)(r>>1) << 8) | (uint32_t)(b>>1);
}

// store the rgb component in our array
void LPD8806_fast::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>>1) | 0x80;
    pixels[n*3+1] = (r>>1) | 0x80;
    pixels[n*3+2] = (b>>1) | 0x80;
}

void LPD8806_fast::setPixelR(uint16_t n, uint8_t r) {
    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed

    pixels[n*3+1] = (r>>1) | 0x80;
}

void LPD8806_fast::setPixelG(uint16_t n, uint8_t g) {
    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed

    pixels[n*3] = (g>>1) | 0x80;
}

void LPD8806_fast::setPixelB(uint16_t n, uint8_t b) {
    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed

    pixels[n*3+2] = (b>>1) | 0x80;
}

// Set all in one function call, assuming GRB ordering
void LPD8806_fast::setPackedPixels(uint8_t * buffer, uint32_t n) {
    if (n >= numLEDs) return;
    for (int i=0; i<n*3; i++)
        buffer[i] = (buffer[i] >> 1) | 0x80;
    memcpy(pixels, buffer, (size_t) (n*3));
}

void LPD8806_fast::setPixelColor(uint16_t n, uint32_t c) {
    if (n >= numLEDs) return; // '>=' because arrays are 0-indexed

    pixels[n*3  ] = (c >> 16) | 0x80;
    pixels[n*3+1] = (c >>  8) | 0x80;
    pixels[n*3+2] =  c        | 0x80;
}
#endif