fastspi_bitbang.h

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#ifndef __INC_FASTSPI_BITBANG_H
#define __INC_FASTSPI_BITBANG_H
 
#include "FastLED.h"
 
#include "fastled_delay.h"
#include "fl/force_inline.h"
 
FASTLED_NAMESPACE_BEGIN


template <uint8_t DATA_PIN, uint8_t CLOCK_PIN, uint32_t SPI_SPEED>
class AVRSoftwareSPIOutput {
    // The data types for pointers to the pin port - typedef'd here from the ::Pin definition because on AVR these
    // are pointers to 8 bit values, while on ARM they are 32 bit
    typedef typename FastPin<DATA_PIN>::port_ptr_t data_ptr_t;
    typedef typename FastPin<CLOCK_PIN>::port_ptr_t clock_ptr_t;
 
    // The data type for what's at a pin's port - typedef'd here from the Pin definition because on avr the ports
    // are 8 bits wide while on arm they are 32.
    typedef typename FastPin<DATA_PIN>::port_t data_t;
    typedef typename FastPin<CLOCK_PIN>::port_t clock_t;
    Selectable    *m_pSelect;  
 
public:
    AVRSoftwareSPIOutput() { m_pSelect = NULL; }
    AVRSoftwareSPIOutput(Selectable *pSelect) { m_pSelect = pSelect; }

    void setSelect(Selectable *pSelect) { m_pSelect = pSelect; }

    void init() {
        // set the pins to output and make sure the select is released (which apparently means hi?  This is a bit
        // confusing to me)
        FastPin<DATA_PIN>::setOutput();
        FastPin<CLOCK_PIN>::setOutput();
        release();
    }

    static void stop() { }

    static void wait() __attribute__((always_inline)) { }
    static void waitFully() __attribute__((always_inline)) { wait(); }

    static void writeByteNoWait(uint8_t b) __attribute__((always_inline)) { writeByte(b); }
    static void writeBytePostWait(uint8_t b) __attribute__((always_inline)) { writeByte(b); wait(); }

    static void writeWord(uint16_t w) __attribute__((always_inline)) { writeByte(w>>8); writeByte(w&0xFF); }

    static void writeByte(uint8_t b) {
        writeBit<7>(b);
        writeBit<6>(b);
        writeBit<5>(b);
        writeBit<4>(b);
        writeBit<3>(b);
        writeBit<2>(b);
        writeBit<1>(b);
        writeBit<0>(b);
    }
 
private:
    static void writeByte(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin)  {
        writeBit<7>(b, clockpin, datapin);
        writeBit<6>(b, clockpin, datapin);
        writeBit<5>(b, clockpin, datapin);
        writeBit<4>(b, clockpin, datapin);
        writeBit<3>(b, clockpin, datapin);
        writeBit<2>(b, clockpin, datapin);
        writeBit<1>(b, clockpin, datapin);
        writeBit<0>(b, clockpin, datapin);
    }

    static void writeByte(uint8_t b, data_ptr_t datapin,
                          data_t hival, data_t loval,
                          clock_t hiclock, clock_t loclock) {
        writeBit<7>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<6>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<5>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<4>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<3>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<2>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<1>(b, datapin, hival, loval, hiclock, loclock);
        writeBit<0>(b, datapin, hival, loval, hiclock, loclock);
    }

    static void writeByte(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin,
                          data_t hival, data_t loval,
                          clock_t hiclock, clock_t loclock) {
        writeBit<7>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<6>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<5>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<4>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<3>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<2>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<1>(b, clockpin, datapin, hival, loval, hiclock, loclock);
        writeBit<0>(b, clockpin, datapin, hival, loval, hiclock, loclock);
    }
 
public:
 
#if defined(FASTLED_TEENSY4)
    #define DELAY_NS (1000 / (SPI_SPEED/1000000))
    #define CLOCK_HI_DELAY do { delayNanoseconds((DELAY_NS/4)); } while(0);
    #define CLOCK_LO_DELAY do { delayNanoseconds((DELAY_NS/4)); } while(0);
#else
    #define MIN_DELAY ((NS(35)>3) ? (NS(35) - 3) : 1)

    #define CLOCK_HI_DELAY do { delaycycles<MIN_DELAY>(); delaycycles<((SPI_SPEED > 10) ? (((SPI_SPEED-6) / 2) - MIN_DELAY) : (SPI_SPEED))>(); } while(0);
    #define CLOCK_LO_DELAY do { delaycycles<((SPI_SPEED > 10) ? ((SPI_SPEED-6) / 2) : (SPI_SPEED))>(); } while(0);
#endif

    template <uint8_t BIT> __attribute__((always_inline, hot)) inline static void writeBit(uint8_t b) {
        //cli();
        if(b & (1 << BIT)) {
            FastPin<DATA_PIN>::hi();
#ifdef ESP32
            // try to ensure we never have adjacent write opcodes to the same register
            FastPin<CLOCK_PIN>::lo();
            FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::toggle(); CLOCK_LO_DELAY;
#else
            FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::lo(); CLOCK_LO_DELAY;
#endif
        } else {
            FastPin<DATA_PIN>::lo();
            FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
#ifdef ESP32
            // try to ensure we never have adjacent write opcodes to the same register
            FastPin<CLOCK_PIN>::toggle(); CLOCK_HI_DELAY;
#else
            FastPin<CLOCK_PIN>::lo(); CLOCK_LO_DELAY;
#endif
        }
        //sei();
    }
 
private:
    template <uint8_t BIT> FASTLED_FORCE_INLINE static void writeBit(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin) {
        if(b & (1 << BIT)) {
            FastPin<DATA_PIN>::hi(datapin);
            FastPin<CLOCK_PIN>::hi(clockpin); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::lo(clockpin); CLOCK_LO_DELAY;
        } else {
            FastPin<DATA_PIN>::lo(datapin);
            FastPin<CLOCK_PIN>::hi(clockpin); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::lo(clockpin); CLOCK_LO_DELAY;
        }
 
    }

    template <uint8_t BIT> FASTLED_FORCE_INLINE static void writeBit(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin,
                                                    data_t hival, data_t loval, clock_t hiclock, clock_t loclock) {
        // // only need to explicitly set clock hi if clock and data are on different ports
        if(b & (1 << BIT)) {
            FastPin<DATA_PIN>::fastset(datapin, hival);
            FastPin<CLOCK_PIN>::fastset(clockpin, hiclock); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::fastset(clockpin, loclock); CLOCK_LO_DELAY;
        } else {
            // FL_NOP;
            FastPin<DATA_PIN>::fastset(datapin, loval);
            FastPin<CLOCK_PIN>::fastset(clockpin, hiclock); CLOCK_HI_DELAY;
            FastPin<CLOCK_PIN>::fastset(clockpin, loclock); CLOCK_LO_DELAY;
        }
    }

    template <uint8_t BIT> FASTLED_FORCE_INLINE static void writeBit(uint8_t b, data_ptr_t clockdatapin,
                                                    data_t datahiclockhi, data_t dataloclockhi,
                                                    data_t datahiclocklo, data_t dataloclocklo) {
#if 0
        writeBit<BIT>(b);
#else
        if(b & (1 << BIT)) {
            FastPin<DATA_PIN>::fastset(clockdatapin, datahiclocklo);
            FastPin<DATA_PIN>::fastset(clockdatapin, datahiclockhi); CLOCK_HI_DELAY;
            FastPin<DATA_PIN>::fastset(clockdatapin, datahiclocklo); CLOCK_LO_DELAY;
        } else {
            // FL_NOP;
            FastPin<DATA_PIN>::fastset(clockdatapin, dataloclocklo);
            FastPin<DATA_PIN>::fastset(clockdatapin, dataloclockhi); CLOCK_HI_DELAY;
            FastPin<DATA_PIN>::fastset(clockdatapin, dataloclocklo); CLOCK_LO_DELAY;
        }
#endif
    }
 
public:

    void select() { if(m_pSelect != NULL) { m_pSelect->select(); } } // FastPin<SELECT_PIN>::hi(); }

    void release() { if(m_pSelect != NULL) { m_pSelect->release(); } } // FastPin<SELECT_PIN>::lo(); }

    void writeBytesValue(uint8_t value, int len) {
        select();
        writeBytesValueRaw(value, len);
        release();
    }

    static void writeBytesValueRaw(uint8_t value, int len) {
#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
        // TODO: Weird things may happen if software bitbanging SPI output and other pins on the output reigsters are being twiddled.  Need
        // to allow specifying whether or not exclusive i/o access is allowed during this process, and if i/o access is not allowed fall
        // back to the degenerative code below
        while(len--) {
            writeByte(value);
        }
#else
        FASTLED_REGISTER data_ptr_t datapin = FastPin<DATA_PIN>::port();
 
        if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
            // If data and clock are on different ports, then writing a bit will consist of writing the value foor
            // the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
            FASTLED_REGISTER clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
            FASTLED_REGISTER data_t datahi = FastPin<DATA_PIN>::hival();
            FASTLED_REGISTER data_t datalo = FastPin<DATA_PIN>::loval();
            FASTLED_REGISTER clock_t clockhi = FastPin<CLOCK_PIN>::hival();
            FASTLED_REGISTER clock_t clocklo = FastPin<CLOCK_PIN>::loval();
            while(len--) {
                writeByte(value, clockpin, datapin, datahi, datalo, clockhi, clocklo);
            }
 
        } else {
            // If data and clock are on the same port then we can combine setting the data and clock pins
            FASTLED_REGISTER data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
 
            while(len--) {
                writeByte(value, datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
            }
        }
#endif
    }

    template <class D> void writeBytes(FASTLED_REGISTER uint8_t *data, int len) {
        select();
#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
        uint8_t *end = data + len;
        while(data != end) {
            writeByte(D::adjust(*data++));
        }
#else
        FASTLED_REGISTER clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
        FASTLED_REGISTER data_ptr_t datapin = FastPin<DATA_PIN>::port();
 
        if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
            // If data and clock are on different ports, then writing a bit will consist of writing the value foor
            // the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
            FASTLED_REGISTER data_t datahi = FastPin<DATA_PIN>::hival();
            FASTLED_REGISTER data_t datalo = FastPin<DATA_PIN>::loval();
            FASTLED_REGISTER clock_t clockhi = FastPin<CLOCK_PIN>::hival();
            FASTLED_REGISTER clock_t clocklo = FastPin<CLOCK_PIN>::loval();
            uint8_t *end = data + len;
 
            while(data != end) {
                writeByte(D::adjust(*data++), clockpin, datapin, datahi, datalo, clockhi, clocklo);
            }
 
        } else {
            // FastPin<CLOCK_PIN>::hi();
            // If data and clock are on the same port then we can combine setting the data and clock pins
            FASTLED_REGISTER data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
 
            uint8_t *end = data + len;
 
            while(data != end) {
                writeByte(D::adjust(*data++), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
            }
            // FastPin<CLOCK_PIN>::lo();
        }
#endif
        D::postBlock(len);
        release();
    }

    void writeBytes(FASTLED_REGISTER uint8_t *data, int len) { writeBytes<DATA_NOP>(data, len); }
 

    template <uint8_t FLAGS, class D, EOrder RGB_ORDER>  __attribute__((noinline)) void writePixels(PixelController<RGB_ORDER> pixels, void* context = NULL) {
        FASTLED_UNUSED(context);
        select();
        int len = pixels.mLen;
 
#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
        // If interrupts or other things may be generating output while we're working on things, then we need
        // to use this block
        while(pixels.has(1)) {
            if(FLAGS & FLAG_START_BIT) {
                writeBit<0>(1);
            }
            writeByte(D::adjust(pixels.loadAndScale0()));
            writeByte(D::adjust(pixels.loadAndScale1()));
            writeByte(D::adjust(pixels.loadAndScale2()));
            pixels.advanceData();
            pixels.stepDithering();
        }
#else
        // If we can guaruntee that no one else will be writing data while we are running (namely, changing the values of the PORT/PDOR pins)
        // then we can use a bunch of optimizations in here
        FASTLED_REGISTER data_ptr_t datapin = FastPin<DATA_PIN>::port();
 
        if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
            FASTLED_REGISTER clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
            // If data and clock are on different ports, then writing a bit will consist of writing the value foor
            // the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
            FASTLED_REGISTER data_t datahi = FastPin<DATA_PIN>::hival();
            FASTLED_REGISTER data_t datalo = FastPin<DATA_PIN>::loval();
            FASTLED_REGISTER clock_t clockhi = FastPin<CLOCK_PIN>::hival();
            FASTLED_REGISTER clock_t clocklo = FastPin<CLOCK_PIN>::loval();
 
            while(pixels.has(1)) {
                if(FLAGS & FLAG_START_BIT) {
                    writeBit<0>(1, clockpin, datapin, datahi, datalo, clockhi, clocklo);
                }
                writeByte(D::adjust(pixels.loadAndScale0()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
                writeByte(D::adjust(pixels.loadAndScale1()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
                writeByte(D::adjust(pixels.loadAndScale2()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
                pixels.advanceData();
                pixels.stepDithering();
            }
 
        } else {
            // If data and clock are on the same port then we can combine setting the data and clock pins
            FASTLED_REGISTER data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
            FASTLED_REGISTER data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
 
            while(pixels.has(1)) {
                if(FLAGS & FLAG_START_BIT) {
                    writeBit<0>(1, datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
                }
                writeByte(D::adjust(pixels.loadAndScale0()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
                writeByte(D::adjust(pixels.loadAndScale1()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
                writeByte(D::adjust(pixels.loadAndScale2()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
                pixels.advanceData();
                pixels.stepDithering();
            }
        }
#endif
        D::postBlock(len);
        release();
    }
};
 
FASTLED_NAMESPACE_END
 
#endif