OctoSK6812.cpp

/*  OctoWS2811 - High Performance WS2811 LED Display Library
    http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
    Copyright (c) 2013 Paul Stoffregen, PJRC.COM, LLC

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
*/

// OctoWS2811 slightly modified to work with SK6812 leds, specifically RGBW leds
// changes made by Mackenzie Hauck nocduro.ca

#include <string.h>
#include "OctoSK6812.h"


uint16_t OctoSK6812::stripLen;
uint8_t OctoSK6812::pixelBits;
void * OctoSK6812::frameBuffer;
void * OctoSK6812::drawBuffer;
uint8_t OctoSK6812::params;
DMAChannel OctoSK6812::dma1;
DMAChannel OctoSK6812::dma2;
DMAChannel OctoSK6812::dma3;

static uint8_t ones = 0xFF;
static volatile uint8_t update_in_progress = 0;
static uint32_t update_completed_at = 0;


OctoSK6812::OctoSK6812(uint32_t numPerStrip, void *frameBuf, void *drawBuf, uint8_t config)
{
  stripLen = numPerStrip;
  frameBuffer = frameBuf;
  drawBuffer = drawBuf;
  params = config;
  if (params > 3) {
    // if RGBW strips we need 32 bits per led
    pixelBits = 32;
  } else {
    pixelBits = 24;
  }
}

// Waveform timing: these set the high time for a 0 and 1 bit, as a fraction of
// the total 800 kHz or 400 kHz clock cycle.  The scale is 0 to 255.  The Worldsemi
// datasheet seems T1H should be 600 ns of a 1250 ns cycle, or 48%.  That may
// erroneous information?  Other sources reason the chip actually samples the
// line close to the center of each bit time, so T1H should be 80% if TOH is 20%.
// The chips appear to work based on a simple one-shot delay triggered by the
// rising edge.  At least 1 chip tested retransmits 0 as a 330 ns pulse (26%) and
// a 1 as a 660 ns pulse (53%).  Perhaps it's actually sampling near 500 ns?
// There doesn't seem to be any advantage to making T1H less, as long as there
// is sufficient low time before the end of the cycle, so the next rising edge
// can be detected.  T0H has been lengthened slightly, because the pulse can
// narrow if the DMA controller has extra latency during bus arbitration.  If you
// have an insight about tuning these parameters AND you have actually tested on
// real LED strips, please contact [email protected].  Please do not email based only
// on reading the datasheets and purely theoretical analysis.
#define SK6812_TIMING_T0H  60
#define SK6812_TIMING_T1H  176

// Discussion about timing and flicker & color shift issues:
// http://forum.pjrc.com/threads/23877-WS2812B-compatible-with-OctoWS2811-library?p=38190&viewfull=1#post38190


void OctoSK6812::begin(void)
{
  uint32_t bufsize, frequency;

  bufsize = stripLen * pixelBits;

  // set up the buffers
  memset(frameBuffer, 0, bufsize);
  if (drawBuffer) {
    memset(drawBuffer, 0, bufsize);
  } else {
    drawBuffer = frameBuffer;
  }
  
  // configure the 8 output pins
  GPIOD_PCOR = 0xFF;
  pinMode(2, OUTPUT);  // strip #1
  pinMode(14, OUTPUT);  // strip #2
  pinMode(7, OUTPUT);  // strip #3
  pinMode(8, OUTPUT);  // strip #4
  pinMode(6, OUTPUT);  // strip #5
  pinMode(20, OUTPUT);  // strip #6
  pinMode(21, OUTPUT);  // strip #7
  pinMode(5, OUTPUT);  // strip #8

  // create the two waveforms for WS2811 low and high bits
  //frequency = (params & WS2811_400kHz) ? 400000 : 800000;
  frequency = 800000;
  analogWriteResolution(8);
  analogWriteFrequency(3, frequency);
  analogWriteFrequency(4, frequency);
  analogWrite(3, SK6812_TIMING_T0H);
  analogWrite(4, SK6812_TIMING_T1H);

#if defined(KINETISK)
  // pin 16 triggers DMA(port B) on rising edge (configure for pin 3's waveform)
  CORE_PIN16_CONFIG = PORT_PCR_IRQC(1)|PORT_PCR_MUX(3);
  pinMode(3, INPUT_PULLUP); // pin 3 no longer needed

  // pin 15 triggers DMA(port C) on falling edge of low duty waveform
  // pin 15 and 16 must be connected by the user: 16 is output, 15 is input
  pinMode(15, INPUT);
  CORE_PIN15_CONFIG = PORT_PCR_IRQC(2)|PORT_PCR_MUX(1);

  // pin 4 triggers DMA(port A) on falling edge of high duty waveform
  CORE_PIN4_CONFIG = PORT_PCR_IRQC(2)|PORT_PCR_MUX(3);

#elif defined(KINETISL)
  // on Teensy-LC, use timer DMA, not pin DMA
  //Serial1.println(FTM2_C0SC, HEX);
  //FTM2_C0SC = 0xA9;
  //FTM2_C0SC = 0xA9;
  //uint32_t t = FTM2_C0SC;
  //FTM2_C0SC = 0xA9;
  //Serial1.println(t, HEX);
  CORE_PIN3_CONFIG = 0;
  CORE_PIN4_CONFIG = 0;
  //FTM2_C0SC = 0;
  //FTM2_C1SC = 0;
  //while (FTM2_C0SC) ;
  //while (FTM2_C1SC) ;
  //FTM2_C0SC = 0x99;
  //FTM2_C1SC = 0x99;

  //MCM_PLACR |= MCM_PLACR_ARB;

#endif

  // DMA channel #1 sets WS2811 high at the beginning of each cycle
  dma1.source(ones);
  dma1.destination(GPIOD_PSOR);
  dma1.transferSize(1);
  dma1.transferCount(bufsize);
  dma1.disableOnCompletion();

  // DMA channel #2 writes the pixel data at 20% of the cycle
  dma2.sourceBuffer((uint8_t *)frameBuffer, bufsize);
  dma2.destination(GPIOD_PDOR);
  dma2.transferSize(1);
  dma2.transferCount(bufsize);
  dma2.disableOnCompletion();

  // DMA channel #3 clear all the pins low at 48% of the cycle
  dma3.source(ones);
  dma3.destination(GPIOD_PCOR);
  dma3.transferSize(1);
  dma3.transferCount(bufsize);
  dma3.disableOnCompletion();
  dma3.interruptAtCompletion();

#ifdef __MK20DX256__
  MCM_CR = MCM_CR_SRAMLAP(1) | MCM_CR_SRAMUAP(0);
  AXBS_PRS0 = 0x1032;
#endif

#if defined(KINETISK)
  // route the edge detect interrupts to trigger the 3 channels
  dma1.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTB);
  dma2.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTC);
  dma3.triggerAtHardwareEvent(DMAMUX_SOURCE_PORTA);
#elif defined(KINETISL)
  // route the timer interrupts to trigger the 3 channels
  dma1.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_OV);
  dma2.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_CH0);
  dma3.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_CH1);
#endif

  // enable a done interrupts when channel #3 completes
  dma3.attachInterrupt(isr);
  //pinMode(9, OUTPUT); // testing: oscilloscope trigger
}

void OctoSK6812::isr(void)
{
  //Serial1.print(".");
  //Serial1.println(dma3.CFG->DCR, HEX);
  //Serial1.print(dma3.CFG->DSR_BCR > 24, HEX);
  dma3.clearInterrupt();
  //Serial1.print("*");
  update_completed_at = micros();
  update_in_progress = 0;
}

int OctoSK6812::busy(void)
{
  if (update_in_progress) return 1;
  // busy for 50 us after the done interrupt, for WS2811 reset
  if (micros() - update_completed_at < 50) return 1;
  return 0;
}

void OctoSK6812::show(void)
{
  // wait for any prior DMA operation
  //Serial1.print("1");
  while (update_in_progress) ; 
  //Serial1.print("2");
  // it's ok to copy the drawing buffer to the frame buffer
  // during the 50us WS2811 reset time
  if (drawBuffer != frameBuffer) {
    // TODO: this could be faster with DMA, especially if the
    // buffers are 32 bit aligned... but does it matter?
    memcpy(frameBuffer, drawBuffer, stripLen * pixelBits);
  }
  // wait for WS2811 reset
  while (micros() - update_completed_at < 50) ;

#if defined(KINETISK)
  // ok to start, but we must be very careful to begin
  // without any prior 3 x 800kHz DMA requests pending
  uint32_t sc = FTM1_SC;
  uint32_t cv = FTM1_C1V;
  noInterrupts();
  // CAUTION: this code is timing critical.  Any editing should be
  // tested by verifying the oscilloscope trigger pulse at the end
  // always occurs while both waveforms are still low.  Simply
  // counting CPU cycles does not take into account other complex
  // factors, like flash cache misses and bus arbitration from USB
  // or other DMA.  Testing should be done with the oscilloscope
  // display set at infinite persistence and a variety of other I/O
  // performed to create realistic bus usage.  Even then, you really
  // should not mess with this timing critical code!
  update_in_progress = 1;
  while (FTM1_CNT <= cv) ; 
  while (FTM1_CNT > cv) ; // wait for beginning of an 800 kHz cycle
  while (FTM1_CNT < cv) ;
  FTM1_SC = sc & 0xE7;  // stop FTM1 timer (hopefully before it rolls over)
  //digitalWriteFast(9, HIGH); // oscilloscope trigger
  PORTB_ISFR = (1<<0);    // clear any prior rising edge
  PORTC_ISFR = (1<<0);  // clear any prior low duty falling edge
  PORTA_ISFR = (1<<13);  // clear any prior high duty falling edge
  dma1.enable();
  dma2.enable();    // enable all 3 DMA channels
  dma3.enable();
  FTM1_SC = sc;    // restart FTM1 timer
  //digitalWriteFast(9, LOW);
#elif defined(KINETISL)
  uint32_t sc = FTM2_SC;
  uint32_t cv = FTM2_C1V;
  noInterrupts();
  update_in_progress = 1;
  while (FTM2_CNT <= cv) ;
  while (FTM2_CNT > cv) ; // wait for beginning of an 800 kHz cycle
  while (FTM2_CNT < cv) ;
  FTM2_SC = 0;    // stop FTM2 timer (hopefully before it rolls over)
  //digitalWriteFast(9, HIGH); // oscilloscope trigger


  dma1.clearComplete();
  dma2.clearComplete();
  dma3.clearComplete();
  uint32_t bufsize = stripLen*pixelBits;
  dma1.transferCount(bufsize);
  dma2.transferCount(bufsize);
  dma3.transferCount(bufsize);
  dma2.sourceBuffer((uint8_t *)frameBuffer, bufsize);

  // clear any pending event flags
  FTM2_SC = 0x80;
  FTM2_C0SC = 0xA9;  // clear any previous pending DMA requests
  FTM2_C1SC = 0xA9;
  // clear any prior pending DMA requests
  dma1.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_OV);
  dma2.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_CH0);
  dma3.triggerAtHardwareEvent(DMAMUX_SOURCE_FTM2_CH1);
  //GPIOD_PTOR = 0xFF;
  //GPIOD_PTOR = 0xFF;
  dma1.enable();
  dma2.enable();    // enable all 3 DMA channels
  dma3.enable();
  FTM2_SC = 0x188;
  //digitalWriteFast(9, LOW);
#endif
  //Serial1.print("3");
  interrupts();
  //Serial1.print("4");
}

void OctoSK6812::setPixel(uint32_t num, int color)
{
  uint32_t strip, offset, mask;
  uint8_t bit, *p;
  
  switch (params) {
    case SK6812_RBG:
    color = (color&0xFF0000) | ((color<<8)&0x00FF00) | ((color>>8)&0x0000FF);
    break;
    case SK6812_GRB:
    color = ((color<<8)&0xFF0000) | ((color>>8)&0x00FF00) | (color&0x0000FF);
    break;
    case SK6812_GBR:
    color = ((color<<8)&0xFFFF00) | ((color>>16)&0x0000FF);
    break;
    case SK6812_GRBW:
    color = ((color<<8)&0xFF000000) | ((color>>8)&0x00FF0000) | (color&0x0000FFFF);
    break;
    default:
    break;
  }
  strip = num / stripLen;  // Cortex-M4 has 2 cycle unsigned divide :-)
  offset = num % stripLen;
  bit = (1<<strip);
  p = ((uint8_t *)drawBuffer) + offset * pixelBits;
  for (mask = (1<<(pixelBits-1)) ; mask ; mask >>= 1) {
    if (color & mask) {
      *p++ |= bit;
    } else {
      *p++ &= ~bit;
    }
  }
}

int OctoSK6812::getPixel(uint32_t num)
{
  uint32_t strip, offset, mask;
  uint8_t bit, *p;
  int color=0;

  strip = num / stripLen;
  offset = num % stripLen;
  bit = (1<<strip);
  p = ((uint8_t *)drawBuffer) + offset * pixelBits;
  for (mask = (1<<(pixelBits-1)) ; mask ; mask >>= 1) {
    if (*p++ & bit) color |= mask;
  }
  
  switch (params) {
    case SK6812_RBG:
    color = (color&0xFF0000) | ((color<<8)&0x00FF00) | ((color>>8)&0x0000FF);
    break;
    case SK6812_GRB:
    color = ((color<<8)&0xFF0000) | ((color>>8)&0x00FF00) | (color&0x0000FF);
    break;
    case SK6812_GBR:
    color = ((color<<8)&0xFFFF00) | ((color>>16)&0x0000FF);
    break;
    case SK6812_GRBW:
    color = ((color<<8)&0xFF000000) | ((color>>8)&0x00FF0000) | (color&0x0000FFFF);
    break;
    default:
    break;
  }

  return color;
}

OctoSK6812.h

/*  OctoWS2811 - High Performance WS2811 LED Display Library
    http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
    Copyright (c) 2013 Paul Stoffregen, PJRC.COM, LLC

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
*/

#ifndef OctoSK6812_h
#define OctoSK6812_h

#include <Arduino.h>
#include "DMAChannel.h"

#if TEENSYDUINO < 121
#error "Teensyduino version 1.21 or later is required to compile this library."
#endif
#ifdef __AVR__
#error "OctoSK6812 does not work with Teensy 2.0 or Teensy++ 2.0."
#endif

#define SK6812_RGB  0  // The WS2811 datasheet documents this way
#define SK6812_RBG  1
#define SK6812_GRB  2  // Most LED strips are wired this way
#define SK6812_GBR  3

#define SK6812_RGBW 4
#define SK6812_GRBW 5

class OctoSK6812 {
public:
  OctoSK6812(uint32_t numPerStrip, void *frameBuf, void *drawBuf, uint8_t config = SK6812_RGB);
  void begin(void);

  void setPixel(uint32_t num, int color);
  void setPixel(uint32_t num, uint8_t red, uint8_t green, uint8_t blue) {
    setPixel(num, color(red, green, blue));
  }
  void setPixel(uint32_t num, uint8_t red, uint8_t green, uint8_t blue, uint8_t white) {
    setPixel(num, color(red, green, blue, white));
  }
  int getPixel(uint32_t num);

  void show(void);
  int busy(void);

  int numPixels(void) {
    return stripLen * 8;
  }
  int color(uint8_t red, uint8_t green, uint8_t blue) {
    return (red << 16) | (green << 8) | blue;
  }
  int color(uint8_t red, uint8_t green, uint8_t blue, uint8_t white) {
    return (red << 24) | (green << 16) | (blue << 8) | white;
  }
  

private:
  static uint16_t stripLen;
  static uint8_t pixelBits;
  static void *frameBuffer;
  static void *drawBuffer;
  static uint8_t params;
  static DMAChannel dma1, dma2, dma3;
  static void isr(void);
};

#endif