File content as of revision 1:c7bb475f0022:

//--------------------------------------------------------
//  SPI を使って WS2812B を点灯するためのクラス
//      サポートするボード： Nucleo-F401RE, Nucleo-F446RE
//
//  2016/11/21, Copyright (c) 2016 MIKAMI, Naoki
//--------------------------------------------------------

#include "WS2812B.h"
#include "PeripheralPins.h"     // for pinmap_peripheral()

WS2812B::WS2812B(PinName pin, bool inv)
    : spi_(pin, NC, NC),
      mySpi_((SPI_TypeDef *)pinmap_peripheral(pin, PinMap_SPI_MOSI))
{
    spi_.format(8, 0);
    // クロックを 23 MHz 以下で最大の値に設定
    //      F401RE: 21.0 MHz
    //      F446RE: 22.5 MHz
#if defined(STM32F446xx)
    spi_.frequency(22500000);
#elif defined(STM32F401xE)
    spi_.frequency(21000000);
#else
#error This code is not move this board.
#endif
    if (!inv) fp = &WS2812B::SendByteNorm;
    else      fp = &WS2812B::SendByteInv;
}

void WS2812B::Write(uint32_t x)
{
    static const uint32_t bit23 = 0x800000;
    for (int n=0; n<24; n++)
    {
        if ((x & bit23) == bit23) T1HL();
        else                      T0HL();
        x <<= 1;
    }
}

void WS2812B::Write(uint32_t x, int k)
{
    for (int n=0; n<k; n++) Write(x);
}  

void WS2812B::Clear(int k)
{
    for (int n=0; n<k; n++) Write(0x000000);
    Reset();
}

void WS2812B::Send3Bytes(uint8_t x0, uint8_t x1, uint8_t x2)
{
    SendByte(x0);
    SendByte(x1);
    SendByte(x2);
}

void WS2812B::SendByteNorm(uint8_t x)
{
    while ((mySpi_->SR & SPI_SR_TXE) != SPI_SR_TXE) {}
    mySpi_->DR = x;
}

void WS2812B::SendByteInv(uint8_t x)
{
    while ((mySpi_->SR & SPI_SR_TXE) != SPI_SR_TXE) {}
    mySpi_->DR = ~x;
}