120 lines
3.1 KiB
C++
120 lines
3.1 KiB
C++
#include "LedDeviceSk6822SPI.h"
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/*
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From the data sheet:
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(TH+TL=1.7μs±600ns)
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T0H, 0 code, high level time, 0.35µs ±0.150ns
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T0L, 0 code, low level time, 1.36µs ±0.150ns
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T1H, 1 code, high level time, 1.36µs ±0.150ns
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T1L, 1 code, low level time, 0.35µs ±0.150ns
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WT, Wait for the processing time, 12µs ±0.150ns
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Trst, Reset code,low level time, 50µs
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To normalise the pulse times so they fit in 4 SPI bits:
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Use timings at upper end of tolerance:
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1.36 -> 1.50 uS
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0.35 -> 0.50 uS
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A SPI bit time of 0.50uS = 2Mbit/sec
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T0 is sent as 1000
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T1 is sent as 1110
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With a bit of excel testing, we can work out the maximum and minimum speeds:
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2000000 MIN
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2230000 AVG
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2460000 MAX
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Wait time:
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using the min of 2000000, the bit time is 0.500
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Wait time is 12uS = 24 bits = 3 bytes
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Reset time:
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using the min of 2000000, the bit time is 0.500
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Reset time is 50uS = 100 bits = 13 bytes
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*/
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LedDeviceSk6822SPI::LedDeviceSk6822SPI(const QJsonObject &deviceConfig)
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: ProviderSpi()
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, SPI_BYTES_PER_COLOUR(4)
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, SPI_BYTES_WAIT_TIME(3)
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, SPI_FRAME_END_LATCH_BYTES(13)
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, bitpair_to_byte {
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0b10001000,
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0b10001110,
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0b11101000,
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0b11101110,
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}
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{
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_devConfig = deviceConfig;
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_deviceReady = false;
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}
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LedDevice* LedDeviceSk6822SPI::construct(const QJsonObject &deviceConfig)
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{
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return new LedDeviceSk6822SPI(deviceConfig);
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}
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bool LedDeviceSk6822SPI::init(const QJsonObject &deviceConfig)
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{
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_baudRate_Hz = 2230000;
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bool isInitOK = ProviderSpi::init(deviceConfig);
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if ( isInitOK )
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{
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WarningIf(( _baudRate_Hz < 2000000 || _baudRate_Hz > 2460000 ), _log, "SPI rate %d outside recommended range (2000000 -> 2460000)", _baudRate_Hz);
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_ledBuffer.resize( (_ledRGBCount * SPI_BYTES_PER_COLOUR) + (_ledCount * SPI_BYTES_WAIT_TIME ) + SPI_FRAME_END_LATCH_BYTES, 0x00);
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// Debug(_log, "_ledBuffer.resize(_ledRGBCount:%d * SPI_BYTES_PER_COLOUR:%d) + ( _ledCount:%d * SPI_BYTES_WAIT_TIME:%d ) + SPI_FRAME_END_LATCH_BYTES:%d, 0x00)", _ledRGBCount, SPI_BYTES_PER_COLOUR, _ledCount, SPI_BYTES_WAIT_TIME, SPI_FRAME_END_LATCH_BYTES);
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}
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return isInitOK;
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}
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int LedDeviceSk6822SPI::write(const std::vector<ColorRgb> &ledValues)
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{
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unsigned spi_ptr = 0;
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const int SPI_BYTES_PER_LED = sizeof(ColorRgb) * SPI_BYTES_PER_COLOUR;
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for (const ColorRgb& color : ledValues)
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{
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uint32_t colorBits = ((unsigned int)color.red << 16)
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| ((unsigned int)color.green << 8)
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| color.blue;
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for (int j=SPI_BYTES_PER_LED - 1; j>=0; j--)
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{
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_ledBuffer[spi_ptr+j] = bitpair_to_byte[ colorBits & 0x3 ];
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colorBits >>= 2;
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}
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spi_ptr += SPI_BYTES_PER_LED;
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spi_ptr += SPI_BYTES_WAIT_TIME; // the wait between led time is all zeros
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}
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/*
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// debug the whole SPI packet
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char debug_line[2048];
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int ptr=0;
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for (unsigned int i=0; i < _ledBuffer.size(); i++)
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{
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if (i%16 == 0)
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{
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ptr += snprintf (ptr+debug_line, sizeof(debug_line)-ptr, "%03x: ", i);
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}
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ptr += snprintf (ptr+debug_line, sizeof(debug_line)-ptr, "%02x ", _ledBuffer.data()[i]);
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if ( (i%16 == 15) || ( i == _ledBuffer.size()-1 ) )
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{
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Debug(_log, debug_line);
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ptr = 0;
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}
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}
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*/
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return writeBytes(_ledBuffer.size(), _ledBuffer.data());
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}
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