134 lines
3.8 KiB
C++
134 lines
3.8 KiB
C++
/*-------------------------------------------------------------------------
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NeoPixel library helper functions for DotStars using SPI hardware (APA102).
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Written by Michael C. Miller.
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I invest time and resources providing this open source code,
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please support me by dontating (see https://github.com/Makuna/NeoPixelBus)
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-------------------------------------------------------------------------
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This file is part of the Makuna/NeoPixelBus library.
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NeoPixelBus is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation, either version 3 of
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the License, or (at your option) any later version.
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NeoPixelBus is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with NeoPixel. If not, see
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<http://www.gnu.org/licenses/>.
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-------------------------------------------------------------------------*/
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#pragma once
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#include <SPI.h>
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class DotStarSpiMethod
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{
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public:
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DotStarSpiMethod(uint16_t pixelCount, size_t elementSize) :
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_sizeData(pixelCount * elementSize),
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_sizeSendBuffer(calcBufferSize(pixelCount * elementSize))
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{
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_sendBuffer = (uint8_t*)malloc(_sizeSendBuffer);
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memset(_sendBuffer, 0, _sizeSendBuffer);
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setEndFrameBytes();
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}
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~DotStarSpiMethod()
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{
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SPI.end();
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free(_sendBuffer);
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}
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bool IsReadyToUpdate() const
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{
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return true; // dot stars don't have a required delay
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}
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#if defined(ARDUINO_ARCH_ESP32)
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void Initialize(int8_t sck, int8_t miso, int8_t mosi, int8_t ss)
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{
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SPI.begin(sck, miso, mosi, ss);
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}
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#endif
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void Initialize()
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{
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SPI.begin();
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}
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void Update(bool)
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{
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SPI.beginTransaction(SPISettings(20000000L, MSBFIRST, SPI_MODE0));
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#if defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32)
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// ESPs have a method to write without inplace overwriting the send buffer
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// since we don't care what gets received, use it for performance
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SPI.writeBytes(_sendBuffer, _sizeSendBuffer);
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#else
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// default ARDUINO transfer inplace overwrites the send buffer
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// which is bad, so we have to send one byte at a time
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uint8_t* out = _sendBuffer;
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uint8_t* end = out + _sizeSendBuffer;
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while (out < end)
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{
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SPI.transfer(*out++);
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}
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#endif
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SPI.endTransaction();
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}
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uint8_t* getPixels() const
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{
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return _sendBuffer + _countStartFrame;
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};
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size_t getPixelsSize() const
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{
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return _sizeData;
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};
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private:
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const size_t _countStartFrame = 4;
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const size_t _sizeData; // size of actuall pixel data within _sendBuffer
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const size_t _sizeSendBuffer; // Size of '_sendBuffer' buffer below
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uint8_t* _sendBuffer; // Holds SPI send Buffer, including LED color values
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size_t calcBufferSize(size_t sizePixels) const
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{
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const size_t countEndFrameBytes = calcEndFrameSize(sizePixels);
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// start frame + data + end frame
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const size_t bufferSize = _countStartFrame + sizePixels + countEndFrameBytes;
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return bufferSize;
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}
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size_t calcEndFrameSize(size_t sizePixels) const
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{
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// end frame
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// one bit for every two pixels with no less than 1 byte
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return ((sizePixels / 4) + 15) / 16;
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}
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void setEndFrameBytes()
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{
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uint8_t* pEndFrame = _sendBuffer + _countStartFrame + _sizeData;
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uint8_t* pEndFrameStop = pEndFrame + calcEndFrameSize(_sizeData);
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while (pEndFrame != pEndFrameStop)
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{
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*pEndFrame++ = 0xff;
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}
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}
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};
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