hyperion.ng/libsrc/leddevice/dev_spi/LedDeviceAPA104.cpp
2020-08-08 00:21:19 +02:00

100 lines
2.2 KiB
C++

#include "LedDeviceAPA104.h"
/*
From the data sheet:
(TH+TL=1.25μs±600ns)
T0H, 0 code, high level time, 350ns ±150ns
T0L, 0 code, low level time, 1360ns ±150ns
T1H, 1 code, high level time, 1360ns ±150ns
T1L, 1 code, low level time, 350ns ±150ns
WT, Wait for the processing time, NA
Trst, Reset code,low level time, 24µs
To normalise the pulse times so they fit in 4 SPI bits:
On the assumption that the "low" time doesnt matter much
A SPI bit time of 0.40uS = 2.5 Mbit/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
2235000 AVG
2470000 MAX
Wait time:
Not Applicable for WS2812
Reset time:
using the max of 2470000, the bit time is 405nS
Reset time is 24uS = 59 bits = 8 bytes
*/
LedDeviceAPA104::LedDeviceAPA104(const QJsonObject &deviceConfig)
: ProviderSpi(deviceConfig)
, SPI_BYTES_PER_COLOUR(4)
, SPI_FRAME_END_LATCH_BYTES(8)
, bitpair_to_byte {
0b10001000,
0b10001110,
0b11101000,
0b11101110,
}
{
}
LedDevice* LedDeviceAPA104::construct(const QJsonObject &deviceConfig)
{
return new LedDeviceAPA104(deviceConfig);
}
bool LedDeviceAPA104::init(const QJsonObject &deviceConfig)
{
_baudRate_Hz = 2235000;
bool isInitOK = false;
// Initialise sub-class
if ( ProviderSpi::init(deviceConfig) )
{
WarningIf(( _baudRate_Hz < 2000000 || _baudRate_Hz > 2470000 ), _log, "SPI rate %d outside recommended range (2000000 -> 2470000)", _baudRate_Hz);
_ledBuffer.resize(_ledRGBCount * SPI_BYTES_PER_COLOUR + SPI_FRAME_END_LATCH_BYTES, 0x00);
isInitOK = true;
}
return isInitOK;
}
int LedDeviceAPA104::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;
}
for (int j=0; j < SPI_FRAME_END_LATCH_BYTES; j++)
{
_ledBuffer[spi_ptr++] = 0;
}
return writeBytes(_ledBuffer.size(), _ledBuffer.data());
}