375 lines
16 KiB
C++
375 lines
16 KiB
C++
#ifndef __INC_FASTSPI_BITBANG_H
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#define __INC_FASTSPI_BITBANG_H
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#include "FastLED.h"
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#include "fastled_delay.h"
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FASTLED_NAMESPACE_BEGIN
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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//
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// Software SPI (aka bit-banging) support - with aggressive optimizations for when the clock and data pin are on the same port
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//
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// TODO: Replace the select pin definition with a set of pins, to allow using mux hardware for routing in the future
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//
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//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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template <uint8_t DATA_PIN, uint8_t CLOCK_PIN, uint8_t SPI_SPEED>
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class AVRSoftwareSPIOutput {
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// The data types for pointers to the pin port - typedef'd here from the Pin definition because on avr these
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// are pointers to 8 bit values, while on arm they are 32 bit
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typedef typename FastPin<DATA_PIN>::port_ptr_t data_ptr_t;
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typedef typename FastPin<CLOCK_PIN>::port_ptr_t clock_ptr_t;
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// The data type for what's at a pin's port - typedef'd here from the Pin definition because on avr the ports
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// are 8 bits wide while on arm they are 32.
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typedef typename FastPin<DATA_PIN>::port_t data_t;
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typedef typename FastPin<CLOCK_PIN>::port_t clock_t;
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Selectable *m_pSelect;
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public:
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AVRSoftwareSPIOutput() { m_pSelect = NULL; }
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AVRSoftwareSPIOutput(Selectable *pSelect) { m_pSelect = pSelect; }
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void setSelect(Selectable *pSelect) { m_pSelect = pSelect; }
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void init() {
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// set the pins to output and make sure the select is released (which apparently means hi? This is a bit
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// confusing to me)
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FastPin<DATA_PIN>::setOutput();
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FastPin<CLOCK_PIN>::setOutput();
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release();
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}
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// stop the SPI output. Pretty much a NOP with software, as there's no registers to kick
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static void stop() { }
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// wait until the SPI subsystem is ready for more data to write. A NOP when bitbanging
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static void wait() __attribute__((always_inline)) { }
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static void waitFully() __attribute__((always_inline)) { wait(); }
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static void writeByteNoWait(uint8_t b) __attribute__((always_inline)) { writeByte(b); }
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static void writeBytePostWait(uint8_t b) __attribute__((always_inline)) { writeByte(b); wait(); }
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static void writeWord(uint16_t w) __attribute__((always_inline)) { writeByte(w>>8); writeByte(w&0xFF); }
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// naive writeByte implelentation, simply calls writeBit on the 8 bits in the byte.
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static void writeByte(uint8_t b) {
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writeBit<7>(b);
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writeBit<6>(b);
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writeBit<5>(b);
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writeBit<4>(b);
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writeBit<3>(b);
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writeBit<2>(b);
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writeBit<1>(b);
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writeBit<0>(b);
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}
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private:
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// writeByte implementation with data/clock registers passed in.
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static void writeByte(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin) {
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writeBit<7>(b, clockpin, datapin);
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writeBit<6>(b, clockpin, datapin);
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writeBit<5>(b, clockpin, datapin);
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writeBit<4>(b, clockpin, datapin);
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writeBit<3>(b, clockpin, datapin);
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writeBit<2>(b, clockpin, datapin);
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writeBit<1>(b, clockpin, datapin);
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writeBit<0>(b, clockpin, datapin);
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}
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// writeByte implementation with the data register passed in and prebaked values for data hi w/clock hi and
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// low and data lo w/clock hi and lo. This is to be used when clock and data are on the same GPIO register,
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// can get close to getting a bit out the door in 2 clock cycles!
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static void writeByte(uint8_t b, data_ptr_t datapin,
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data_t hival, data_t loval,
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clock_t hiclock, clock_t loclock) {
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writeBit<7>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<6>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<5>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<4>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<3>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<2>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<1>(b, datapin, hival, loval, hiclock, loclock);
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writeBit<0>(b, datapin, hival, loval, hiclock, loclock);
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}
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// writeByte implementation with not just registers passed in, but pre-baked values for said registers for
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// data hi/lo and clock hi/lo values. Note: weird things will happen if this method is called in cases where
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// the data and clock pins are on the same port! Don't do that!
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static void writeByte(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin,
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data_t hival, data_t loval,
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clock_t hiclock, clock_t loclock) {
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writeBit<7>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<6>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<5>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<4>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<3>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<2>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<1>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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writeBit<0>(b, clockpin, datapin, hival, loval, hiclock, loclock);
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}
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public:
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// We want to make sure that the clock pulse is held high for a nininum of 35ns.
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#define MIN_DELAY (NS(35) - 3)
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#define CLOCK_HI_DELAY delaycycles<MIN_DELAY>(); delaycycles<(((SPI_SPEED-6) / 2) - MIN_DELAY)>();
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#define CLOCK_LO_DELAY delaycycles<(((SPI_SPEED-6) / 4))>();
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// write the BIT'th bit out via spi, setting the data pin then strobing the clcok
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template <uint8_t BIT> __attribute__((always_inline, hot)) inline static void writeBit(uint8_t b) {
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//cli();
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if(b & (1 << BIT)) {
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FastPin<DATA_PIN>::hi();
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#ifdef ESP32
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// try to ensure we never have adjacent write opcodes to the same register
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FastPin<CLOCK_PIN>::lo();
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FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::toggle(); CLOCK_LO_DELAY;
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#else
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FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::lo(); CLOCK_LO_DELAY;
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#endif
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} else {
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FastPin<DATA_PIN>::lo();
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FastPin<CLOCK_PIN>::hi(); CLOCK_HI_DELAY;
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#ifdef ESP32
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// try to ensure we never have adjacent write opcodes to the same register
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FastPin<CLOCK_PIN>::toggle(); CLOCK_HI_DELAY;
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#else
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FastPin<CLOCK_PIN>::lo(); CLOCK_LO_DELAY;
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#endif
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}
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//sei();
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}
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private:
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// write the BIT'th bit out via spi, setting the data pin then strobing the clock, using the passed in pin registers to accelerate access if needed
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template <uint8_t BIT> __attribute__((always_inline)) inline static void writeBit(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin) {
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if(b & (1 << BIT)) {
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FastPin<DATA_PIN>::hi(datapin);
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FastPin<CLOCK_PIN>::hi(clockpin); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::lo(clockpin); CLOCK_LO_DELAY;
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} else {
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FastPin<DATA_PIN>::lo(datapin);
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FastPin<CLOCK_PIN>::hi(clockpin); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::lo(clockpin); CLOCK_LO_DELAY;
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}
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}
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// the version of write to use when clock and data are on separate pins with precomputed values for setting
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// the clock and data pins
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template <uint8_t BIT> __attribute__((always_inline)) inline static void writeBit(uint8_t b, clock_ptr_t clockpin, data_ptr_t datapin,
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data_t hival, data_t loval, clock_t hiclock, clock_t loclock) {
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// // only need to explicitly set clock hi if clock and data are on different ports
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if(b & (1 << BIT)) {
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FastPin<DATA_PIN>::fastset(datapin, hival);
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FastPin<CLOCK_PIN>::fastset(clockpin, hiclock); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::fastset(clockpin, loclock); CLOCK_LO_DELAY;
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} else {
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// FL_NOP;
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FastPin<DATA_PIN>::fastset(datapin, loval);
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FastPin<CLOCK_PIN>::fastset(clockpin, hiclock); CLOCK_HI_DELAY;
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FastPin<CLOCK_PIN>::fastset(clockpin, loclock); CLOCK_LO_DELAY;
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}
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}
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// the version of write to use when clock and data are on the same port with precomputed values for the various
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// combinations
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template <uint8_t BIT> __attribute__((always_inline)) inline static void writeBit(uint8_t b, data_ptr_t clockdatapin,
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data_t datahiclockhi, data_t dataloclockhi,
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data_t datahiclocklo, data_t dataloclocklo) {
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#if 0
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writeBit<BIT>(b);
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#else
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if(b & (1 << BIT)) {
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FastPin<DATA_PIN>::fastset(clockdatapin, datahiclocklo);
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FastPin<DATA_PIN>::fastset(clockdatapin, datahiclockhi); CLOCK_HI_DELAY;
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FastPin<DATA_PIN>::fastset(clockdatapin, datahiclocklo); CLOCK_LO_DELAY;
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} else {
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// FL_NOP;
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FastPin<DATA_PIN>::fastset(clockdatapin, dataloclocklo);
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FastPin<DATA_PIN>::fastset(clockdatapin, dataloclockhi); CLOCK_HI_DELAY;
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FastPin<DATA_PIN>::fastset(clockdatapin, dataloclocklo); CLOCK_LO_DELAY;
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}
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#endif
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}
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public:
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// select the SPI output (TODO: research whether this really means hi or lo. Alt TODO: move select responsibility out of the SPI classes
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// entirely, make it up to the caller to remember to lock/select the line?)
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void select() { if(m_pSelect != NULL) { m_pSelect->select(); } } // FastPin<SELECT_PIN>::hi(); }
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// release the SPI line
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void release() { if(m_pSelect != NULL) { m_pSelect->release(); } } // FastPin<SELECT_PIN>::lo(); }
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// Write out len bytes of the given value out over SPI. Useful for quickly flushing, say, a line of 0's down the line.
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void writeBytesValue(uint8_t value, int len) {
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select();
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writeBytesValueRaw(value, len);
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release();
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}
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static void writeBytesValueRaw(uint8_t value, int len) {
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#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
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// TODO: Weird things may happen if software bitbanging SPI output and other pins on the output reigsters are being twiddled. Need
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// to allow specifying whether or not exclusive i/o access is allowed during this process, and if i/o access is not allowed fall
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// back to the degenerative code below
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while(len--) {
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writeByte(value);
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}
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#else
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register data_ptr_t datapin = FastPin<DATA_PIN>::port();
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if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
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// If data and clock are on different ports, then writing a bit will consist of writing the value foor
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// the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
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register clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
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register data_t datahi = FastPin<DATA_PIN>::hival();
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register data_t datalo = FastPin<DATA_PIN>::loval();
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register clock_t clockhi = FastPin<CLOCK_PIN>::hival();
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register clock_t clocklo = FastPin<CLOCK_PIN>::loval();
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while(len--) {
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writeByte(value, clockpin, datapin, datahi, datalo, clockhi, clocklo);
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}
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} else {
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// If data and clock are on the same port then we can combine setting the data and clock pins
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register data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
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register data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
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while(len--) {
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writeByte(value, datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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}
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}
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#endif
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}
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// write a block of len uint8_ts out. Need to type this better so that explicit casts into the call aren't required.
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// note that this template version takes a class parameter for a per-byte modifier to the data.
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template <class D> void writeBytes(register uint8_t *data, int len) {
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select();
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#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
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uint8_t *end = data + len;
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while(data != end) {
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writeByte(D::adjust(*data++));
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}
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#else
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register clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
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register data_ptr_t datapin = FastPin<DATA_PIN>::port();
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if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
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// If data and clock are on different ports, then writing a bit will consist of writing the value foor
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// the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
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register data_t datahi = FastPin<DATA_PIN>::hival();
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register data_t datalo = FastPin<DATA_PIN>::loval();
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register clock_t clockhi = FastPin<CLOCK_PIN>::hival();
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register clock_t clocklo = FastPin<CLOCK_PIN>::loval();
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uint8_t *end = data + len;
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while(data != end) {
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writeByte(D::adjust(*data++), clockpin, datapin, datahi, datalo, clockhi, clocklo);
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}
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} else {
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// FastPin<CLOCK_PIN>::hi();
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// If data and clock are on the same port then we can combine setting the data and clock pins
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register data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
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register data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
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uint8_t *end = data + len;
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while(data != end) {
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writeByte(D::adjust(*data++), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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}
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// FastPin<CLOCK_PIN>::lo();
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}
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#endif
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D::postBlock(len);
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release();
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}
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// default version of writing a block of data out to the SPI port, with no data modifications being made
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void writeBytes(register uint8_t *data, int len) { writeBytes<DATA_NOP>(data, len); }
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// write a block of uint8_ts out in groups of three. len is the total number of uint8_ts to write out. The template
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// parameters indicate how many uint8_ts to skip at the beginning of each grouping, as well as a class specifying a per
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// byte of data modification to be made. (See DATA_NOP above)
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template <uint8_t FLAGS, class D, EOrder RGB_ORDER> __attribute__((noinline)) void writePixels(PixelController<RGB_ORDER> pixels) {
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select();
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int len = pixels.mLen;
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#ifdef FAST_SPI_INTERRUPTS_WRITE_PINS
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// If interrupts or other things may be generating output while we're working on things, then we need
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// to use this block
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while(pixels.has(1)) {
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if(FLAGS & FLAG_START_BIT) {
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writeBit<0>(1);
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}
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writeByte(D::adjust(pixels.loadAndScale0()));
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writeByte(D::adjust(pixels.loadAndScale1()));
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writeByte(D::adjust(pixels.loadAndScale2()));
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pixels.advanceData();
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pixels.stepDithering();
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}
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#else
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// 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)
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// then we can use a bunch of optimizations in here
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register data_ptr_t datapin = FastPin<DATA_PIN>::port();
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if(FastPin<DATA_PIN>::port() != FastPin<CLOCK_PIN>::port()) {
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register clock_ptr_t clockpin = FastPin<CLOCK_PIN>::port();
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// If data and clock are on different ports, then writing a bit will consist of writing the value foor
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// the bit (hi or low) to the data pin port, and then two writes to the clock port to strobe the clock line
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register data_t datahi = FastPin<DATA_PIN>::hival();
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register data_t datalo = FastPin<DATA_PIN>::loval();
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register clock_t clockhi = FastPin<CLOCK_PIN>::hival();
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register clock_t clocklo = FastPin<CLOCK_PIN>::loval();
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while(pixels.has(1)) {
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if(FLAGS & FLAG_START_BIT) {
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writeBit<0>(1, clockpin, datapin, datahi, datalo, clockhi, clocklo);
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}
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writeByte(D::adjust(pixels.loadAndScale0()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
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writeByte(D::adjust(pixels.loadAndScale1()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
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writeByte(D::adjust(pixels.loadAndScale2()), clockpin, datapin, datahi, datalo, clockhi, clocklo);
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pixels.advanceData();
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pixels.stepDithering();
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}
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} else {
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// If data and clock are on the same port then we can combine setting the data and clock pins
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register data_t datahi_clockhi = FastPin<DATA_PIN>::hival() | FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clockhi = FastPin<DATA_PIN>::loval() | FastPin<CLOCK_PIN>::mask();
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register data_t datahi_clocklo = FastPin<DATA_PIN>::hival() & ~FastPin<CLOCK_PIN>::mask();
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register data_t datalo_clocklo = FastPin<DATA_PIN>::loval() & ~FastPin<CLOCK_PIN>::mask();
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while(pixels.has(1)) {
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if(FLAGS & FLAG_START_BIT) {
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writeBit<0>(1, datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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}
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writeByte(D::adjust(pixels.loadAndScale0()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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writeByte(D::adjust(pixels.loadAndScale1()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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writeByte(D::adjust(pixels.loadAndScale2()), datapin, datahi_clockhi, datalo_clockhi, datahi_clocklo, datalo_clocklo);
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pixels.advanceData();
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pixels.stepDithering();
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}
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}
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#endif
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D::postBlock(len);
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release();
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}
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};
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FASTLED_NAMESPACE_END
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#endif
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