hyperion.ng/libsrc/leddevice/LedDeviceSk6822SPI.cpp

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[untested] added Sk6822 led device support (#397) * Adding support for sk6822 timing This isnt complete, but should be a good starting point for others to learn from. 1) Here is where the led device source is located: cd libsrc/leddevice 2) Find the files that need changing: root@loungepi:libsrc/leddevice# grep -ri 2812spi * CMakeLists.txt: ${CURRENT_SOURCE_DIR}/LedDeviceWs2812SPI.h CMakeLists.txt: ${CURRENT_SOURCE_DIR}/LedDeviceWs2812SPI.cpp LedDeviceFactory.cpp: #include "LedDeviceWs2812SPI.h" LedDeviceFactory.cpp: REGISTER(Ws2812SPI); LedDeviceSchemas.qrc: <file alias="schema-ws2812spi">schemas/schema-ws2812spi.json</file> LedDeviceWs2812SPI.cpp:#include "LedDeviceWs2812SPI.h" LedDeviceWs2812SPI.cpp:LedDeviceWs2812SPI::LedDeviceWs2812SPI(const QJsonObject &deviceConfig) LedDeviceWs2812SPI.cpp:LedDevice* LedDeviceWs2812SPI::construct(const QJsonObject &deviceConfig) LedDeviceWs2812SPI.cpp: return new LedDeviceWs2812SPI(deviceConfig); LedDeviceWs2812SPI.cpp:bool LedDeviceWs2812SPI::init(const QJsonObject &deviceConfig) LedDeviceWs2812SPI.cpp:int LedDeviceWs2812SPI::write(const std::vector<ColorRgb> &ledValues) LedDeviceWs2812SPI.h:class LedDeviceWs2812SPI : public ProviderSpi LedDeviceWs2812SPI.h: LedDeviceWs2812SPI(const QJsonObject &deviceConfig); 3) Copy the existing files as a starting point: cp LedDeviceWs2812SPI.cpp LedDeviceSk6822SPI.cpp cp LedDeviceWs2812SPI.h LedDeviceSk6822SPI.h cp schemas/schema-ws2812spi.json schemas/schema-sk6822spi.json 4) Do some search and replacing: :%s/Ws2812SPI/Sk6822SPI/g 5) edit the other files (see the diffs in this commit) * Added wait time and reset time * Fixed up debugging output and commented it out.
2017-02-14 09:33:28 +01:00
#include "LedDeviceSk6822SPI.h"
/*
From the data sheet:
(TH+TL=1.7μs±600ns)
T0H, 0 code, high level time, 0.35µs ±0.150ns
T0L, 0 code, low level time, 1.36µs ±0.150ns
T1H, 1 code, high level time, 1.36µs ±0.150ns
T1L, 1 code, low level time, 0.35µs ±0.150ns
WT, Wait for the processing time, 12µs ±0.150ns
Trst, Reset code,low level time, 50µs
To normalise the pulse times so they fit in 4 SPI bits:
Use timings at upper end of tolerance:
1.36 -> 1.50 uS
0.35 -> 0.50 uS
A SPI bit time of 0.50uS = 2Mbit/sec
T0 is sent as 1000
T1 is sent as 1110
With a bit of excel testing, we can work out the maximum and minimum speeds:
2000000 MIN
2230000 AVG
2460000 MAX
Wait time:
using the min of 2000000, the bit time is 0.500
Wait time is 12uS = 24 bits = 3 bytes
Reset time:
using the min of 2000000, the bit time is 0.500
Reset time is 50uS = 100 bits = 13 bytes
*/
LedDeviceSk6822SPI::LedDeviceSk6822SPI(const QJsonObject &deviceConfig)
: ProviderSpi()
, SPI_BYTES_PER_COLOUR(4)
, SPI_BYTES_WAIT_TIME(3)
, SPI_FRAME_END_LATCH_BYTES(13)
, bitpair_to_byte {
0b10001000,
0b10001110,
0b11101000,
0b11101110,
}
{
_deviceReady = init(deviceConfig);
}
LedDevice* LedDeviceSk6822SPI::construct(const QJsonObject &deviceConfig)
{
return new LedDeviceSk6822SPI(deviceConfig);
}
bool LedDeviceSk6822SPI::init(const QJsonObject &deviceConfig)
{
_baudRate_Hz = 2230000;
if ( !ProviderSpi::init(deviceConfig) )
{
return false;
}
WarningIf(( _baudRate_Hz < 2000000 || _baudRate_Hz > 2460000 ), _log, "SPI rate %d outside recommended range (2000000 -> 2460000)", _baudRate_Hz);
_ledBuffer.resize( (_ledRGBCount * SPI_BYTES_PER_COLOUR) + (_ledCount * SPI_BYTES_WAIT_TIME ) + SPI_FRAME_END_LATCH_BYTES, 0x00);
// 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);
return true;
}
int LedDeviceSk6822SPI::write(const std::vector<ColorRgb> &ledValues)
{
unsigned spi_ptr = 0;
const int SPI_BYTES_PER_LED = sizeof(ColorRgb) * SPI_BYTES_PER_COLOUR;
for (const ColorRgb& color : ledValues)
{
uint32_t colorBits = ((unsigned int)color.red << 16)
| ((unsigned int)color.green << 8)
| color.blue;
for (int j=SPI_BYTES_PER_LED - 1; j>=0; j--)
{
_ledBuffer[spi_ptr+j] = bitpair_to_byte[ colorBits & 0x3 ];
colorBits >>= 2;
}
spi_ptr += SPI_BYTES_PER_LED;
spi_ptr += SPI_BYTES_WAIT_TIME; // the wait between led time is all zeros
}
/*
// debug the whole SPI packet
char debug_line[2048];
int ptr=0;
for (unsigned int i=0; i < _ledBuffer.size(); i++)
{
if (i%16 == 0)
{
ptr += snprintf (ptr+debug_line, sizeof(debug_line)-ptr, "%03x: ", i);
}
ptr += snprintf (ptr+debug_line, sizeof(debug_line)-ptr, "%02x ", _ledBuffer.data()[i]);
if ( (i%16 == 15) || ( i == _ledBuffer.size()-1 ) )
{
Debug(_log, debug_line);
ptr = 0;
}
}
*/
return writeBytes(_ledBuffer.size(), _ledBuffer.data());
}