ST7789v_arduino.cpp

/***************************************************
  This is a library for the ST7789 IPS SPI display.

  Originally written by Limor Fried/Ladyada for 
  Adafruit Industries.

  Modified by Ananev Ilia
  Modified by Kamran Gasimov
 ****************************************************/

#include "ST7789v_arduino.h"
#include <limits.h>
#include "pins_arduino.h"
#include "wiring_private.h"
#include "SPI.h"
// #include <PI.h >

static const uint8_t PROGMEM
  cmd_240x240[] = {                     // Initialization commands for 7789 screens
    10,                               // 9 commands in list:
    ST7789_SWRESET,   ST_CMD_DELAY,     // 1: Software reset, no args, w/delay
      150,                            // 150 ms delay
    ST7789_SLPOUT ,   ST_CMD_DELAY,     // 2: Out of sleep mode, no args, w/delay
      255,                            // 255 = 500 ms delay
    ST7789_COLMOD , 1+ST_CMD_DELAY,     // 3: Set color mode, 1 arg + delay:
      0x55,                           // 16-bit color
      10,                             // 10 ms delay
    ST7789_MADCTL , 1,            // 4: Memory access ctrl (directions), 1 arg:
      0x00,                           // Row addr/col addr, bottom to top refresh
    ST7789_CASET  , 4,            // 5: Column addr set, 4 args, no delay:
      0x00, ST7789_240x240_XSTART,          // XSTART = 0
    (ST7789_TFTWIDTH+ST7789_240x240_XSTART) >> 8,
    (ST7789_TFTWIDTH+ST7789_240x240_XSTART) & 0xFF,   // XEND = 240
    ST7789_RASET  , 4,            // 6: Row addr set, 4 args, no delay:
      0x00, ST7789_240x240_YSTART,          // YSTART = 0
      (ST7789_TFTHEIGHT+ST7789_240x240_YSTART) >> 8,
    (ST7789_TFTHEIGHT+ST7789_240x240_YSTART) & 0xFF,  // YEND = 240
    ST7789_INVON ,   ST_CMD_DELAY,      // 7: Inversion ON
      10,
    ST7789_NORON  ,   ST_CMD_DELAY,     // 8: Normal display on, no args, w/delay
      10,                             // 10 ms delay
    ST7789_DISPON ,   ST_CMD_DELAY,     // 9: Main screen turn on, no args, w/delay
    255 };                          // 255 = 500 ms delay

inline uint16_t swapcolor(uint16_t x) { 
  return (x << 11) | (x & 0x07E0) | (x >> 11);
}

// #if defined (SPI_HAS_TRANSACTION)
  static SPISettings mySPISettings;
// #elif defined (__AVR__) || defined(CORE_TEENSY) 
//   static uint8_t SPCRbackup;
//   static uint8_t mySPCR;
// #endif


#if defined (SPI_HAS_TRANSACTION)
#define SPI_BEGIN_TRANSACTION()    if (_hwSPI)    SPI.begin();
#define SPI_END_TRANSACTION()      if (_hwSPI)    SPI.endTransaction()
#else
#define SPI_BEGIN_TRANSACTION()    if (_hwSPI)    SPI.begin();
#define SPI_END_TRANSACTION()      if (_hwSPI)    SPI.endTransaction()
#endif

// Constructor when using software SPI.  All output pins are configurable.
ST7789v_arduino::ST7789v_arduino(int8_t dc, int8_t rst, int8_t sid, int8_t sclk, int8_t cs) 
  : Adafruit_GFX(ST7789_TFTWIDTH, ST7789_TFTHEIGHT)
{
  _cs   = cs;
  _dc   = dc;
  _sid  = sid;
  _sclk = sclk;
  _rst  = rst;
  _hwSPI = false;
  if(dc == -1) _SPI9bit = true;
  else _SPI9bit = false;  
}

// Constructor when using hardware SPI.  Faster, but must use SPI pins
// specific to each board type (e.g. 11,13 for Uno, 51,52 for Mega, etc.)
ST7789v_arduino::ST7789v_arduino(int8_t dc, int8_t rst, int8_t cs) 
  : Adafruit_GFX(ST7789_TFTWIDTH, ST7789_TFTHEIGHT) {
  _cs   = cs;
  _dc   = dc;
  _rst  = rst;
  _hwSPI = true;
  _SPI9bit = false;
  _sid  = _sclk = -1;
}

inline void ST7789v_arduino::spiwrite(uint8_t c) 
{

  //Serial.println(c, HEX);

  if (_hwSPI) 
  {
#if defined (SPI_HAS_TRANSACTION)
      SPI.transfer(c);
#elif defined (__AVR__) || defined(CORE_TEENSY)
      SPCRbackup = SPCR;
      SPCR = mySPCR;
      SPI.transfer(c);
      SPCR = SPCRbackup;
#elif defined (__arm__)
      SPI.setClockDivider(21); //4MHz
      SPI.setDataMode(SPI_MODE2);
      SPI.transfer(c);
#endif
  }
  else 
  {
    if(_SPI9bit)
    {
    //9s bit send first
#if defined(USE_FAST_IO)
    *clkport &= ~clkpinmask;
    if(_DCbit) *dataport |=  datapinmask;
    else        *dataport &= ~datapinmask;
    *clkport |=  clkpinmask;
#else
    digitalWrite(_sclk, LOW);
    if(_DCbit) digitalWrite(_sid, HIGH);
    else        digitalWrite(_sid, LOW);
    digitalWrite(_sclk, HIGH);
#endif
    
    
    // Fast SPI bitbang swiped from LPD8806 library
    for(uint8_t bit = 0x80; bit; bit >>= 1) {
#if defined(USE_FAST_IO)
    *clkport &= ~clkpinmask;
    if(c & bit) *dataport |=  datapinmask;
    else        *dataport &= ~datapinmask;
    *clkport |=  clkpinmask;
#else
    digitalWrite(_sclk, LOW);
    if(c & bit) digitalWrite(_sid, HIGH);
    else        digitalWrite(_sid, LOW);
    digitalWrite(_sclk, HIGH);
#endif
      
    }
    }
    else
    {
      // Fast SPI bitbang swiped from LPD8806 library
    for(uint8_t bit = 0x80; bit; bit >>= 1) {
#if defined(USE_FAST_IO)
    *clkport &= ~clkpinmask;
    if(c & bit) *dataport |=  datapinmask;
    else        *dataport &= ~datapinmask;
    *clkport |=  clkpinmask;
#else
    digitalWrite(_sclk, LOW);
    if(c & bit) digitalWrite(_sid, HIGH);
    else        digitalWrite(_sid, LOW);
    digitalWrite(_sclk, HIGH);
#endif
    }
  }
  }
}

void ST7789v_arduino::writecommand(uint8_t c) {

  DC_LOW();
  CS_LOW();
  SPI_BEGIN_TRANSACTION();

  spiwrite(c);

  CS_HIGH();
  SPI_END_TRANSACTION();
}

void ST7789v_arduino::writedata(uint8_t c) {
  SPI_BEGIN_TRANSACTION();
  DC_HIGH();
  CS_LOW();
    
  spiwrite(c);

  CS_HIGH();
  SPI_END_TRANSACTION();
}

// Companion code to the above tables.  Reads and issues
// a series of LCD commands stored in PROGMEM byte array.
void ST7789v_arduino::displayInit(const uint8_t *addr) {

  uint8_t  numCommands, numArgs;
  uint16_t ms;
  //<-----------------------------------------------------------------------------------------
  DC_HIGH();
  #if defined(USE_FAST_IO)
      *clkport |=  clkpinmask;
  #else
      digitalWrite(_sclk, HIGH);
  #endif
  //<-----------------------------------------------------------------------------------------

  numCommands = pgm_read_byte(addr++);   // Number of commands to follow
  while(numCommands--) {                 // For each command...
    writecommand(pgm_read_byte(addr++)); //   Read, issue command
    numArgs  = pgm_read_byte(addr++);    //   Number of args to follow
    ms       = numArgs & ST_CMD_DELAY;   //   If hibit set, delay follows args
    numArgs &= ~ST_CMD_DELAY;            //   Mask out delay bit
    while(numArgs--) {                   //   For each argument...
      writedata(pgm_read_byte(addr++));  //     Read, issue argument
    }

    if(ms) {
      ms = pgm_read_byte(addr++); // Read post-command delay time (ms)
      if(ms == 255) ms = 500;     // If 255, delay for 500 ms
      delay(ms);
    }
  }
}


// Initialization code common to all ST7789 displays
void ST7789v_arduino::commonInit(const uint8_t *cmdList) {
  _ystart = _xstart = 0;
  _colstart  = _rowstart = 0; // May be overridden in init func

  pinMode(_dc, OUTPUT);
  if(_cs) {
    pinMode(_cs, OUTPUT);
  }

#if defined(USE_FAST_IO)
  dcport    = portOutputRegister(digitalPinToPort(_dc));
  dcpinmask = digitalPinToBitMask(_dc);
  if(_cs) {
  csport    = portOutputRegister(digitalPinToPort(_cs));
  cspinmask = digitalPinToBitMask(_cs);
  }
  
#endif

  if(_hwSPI) { // Using hardware SPI
// #if defined (SPI_HAS_TRANSACTION)
    SPI.begin();
    SPI.setClockDivider(SPI_CLOCK_DIV2);
    mySPISettings = SPISettings(0, MSBFIRST, SPI_MODE2);
    
// #elif defined (__AVR__) || defined(CORE_TEENSY)
//     SPCRbackup = SPCR;
//     SPI.begin();
//     SPI.setClockDivider(SPI_CLOCK_DIV4);
//     SPI.setDataMode(SPI_MODE2);
//     mySPCR = SPCR; // save our preferred state
//     SPCR = SPCRbackup;  // then restore
// #elif defined (__SAM3X8E__)
//     SPI.begin();
//     SPI.setClockDivider(21); //4MHz
//     SPI.setDataMode(SPI_MODE2);
// #endif
  } else {
    pinMode(_sclk, OUTPUT);
    pinMode(_sid , OUTPUT);
    digitalWrite(_sclk, LOW);
    digitalWrite(_sid, LOW);

#if defined(USE_FAST_IO)
    clkport     = portOutputRegister(digitalPinToPort(_sclk));
    dataport    = portOutputRegister(digitalPinToPort(_sid));
    clkpinmask  = digitalPinToBitMask(_sclk);
    datapinmask = digitalPinToBitMask(_sid);
#endif
  }

  // toggle RST low to reset; CS low so it'll listen to us
  CS_LOW();
  if (_rst != -1) {
    pinMode(_rst, OUTPUT);
    digitalWrite(_rst, HIGH);
    delay(50);
    digitalWrite(_rst, LOW);
    delay(50);
    digitalWrite(_rst, HIGH);
    delay(50);
  }

  if(cmdList) 
    displayInit(cmdList);
}

void ST7789v_arduino::setRotation(uint8_t m) {

  writecommand(ST7789_MADCTL);
  rotation = m % 4; // can't be higher than 3
  switch (rotation) {
   case 0:
     writedata(ST7789_MADCTL_MX | ST7789_MADCTL_MY | ST7789_MADCTL_RGB);

     _xstart = _colstart;
     _ystart = _rowstart;
     break;
   case 1:
     writedata(ST7789_MADCTL_MY | ST7789_MADCTL_MV | ST7789_MADCTL_RGB);

     _ystart = _colstart;
     _xstart = _rowstart;
     break;
  case 2:
     writedata(ST7789_MADCTL_RGB);
 
     _xstart = _colstart;
     _ystart = _rowstart;
     break;

   case 3:
     writedata(ST7789_MADCTL_MX | ST7789_MADCTL_MV | ST7789_MADCTL_RGB);

     _ystart = _colstart;
     _xstart = _rowstart;
     break;
  }
}

void ST7789v_arduino::setAddrWindow(uint16_t x0, uint16_t y0, uint16_t x1,
 uint16_t y1) {

  uint16_t x_start = x0 + _xstart, x_end = x1 + _xstart;
  uint16_t y_start = y0 + _ystart, y_end = y1 + _ystart;
  

  writecommand(ST7789_CASET); // Column addr set
  writedata(x_start >> 8);
  writedata(x_start & 0xFF);     // XSTART 
  writedata(x_end >> 8);
  writedata(x_end & 0xFF);     // XEND

  writecommand(ST7789_RASET); // Row addr set
  writedata(y_start >> 8);
  writedata(y_start & 0xFF);     // YSTART
  writedata(y_end >> 8);
  writedata(y_end & 0xFF);     // YEND

  writecommand(ST7789_RAMWR); // write to RAM
}

void ST7789v_arduino::pushColor(uint16_t color) {
  SPI_BEGIN_TRANSACTION();
  DC_HIGH();
  CS_LOW();

  spiwrite(color >> 8);
  spiwrite(color);

  CS_HIGH();
  SPI_END_TRANSACTION();
}

void ST7789v_arduino::drawPixel(int16_t x, int16_t y, uint16_t color) {

  if((x < 0) ||(x >= _width) || (y < 0) || (y >= _height)) return;

  setAddrWindow(x,y,x+1,y+1);

  SPI_BEGIN_TRANSACTION();
  DC_HIGH();
  CS_LOW();

  spiwrite(color >> 8);
  spiwrite(color);

  CS_HIGH();
  SPI_END_TRANSACTION();
}

void ST7789v_arduino::drawFastVLine(int16_t x, int16_t y, int16_t h,
 uint16_t color) {

  // Rudimentary clipping
  if((x >= _width) || (y >= _height)) return;
  if((y+h-1) >= _height) h = _height-y;
  setAddrWindow(x, y, x, y+h-1);

  uint8_t hi = color >> 8, lo = color;
    
  SPI_BEGIN_TRANSACTION();
  DC_HIGH();
  CS_LOW();

  while (h--) {
    spiwrite(hi);
    spiwrite(lo);
  }

  CS_HIGH();
  SPI_END_TRANSACTION();
}

void ST7789v_arduino::drawFastHLine(int16_t x, int16_t y, int16_t w,
  uint16_t color) {

  // Rudimentary clipping
  if((x >= _width) || (y >= _height)) return;
  if((x+w-1) >= _width)  w = _width-x;
  setAddrWindow(x, y, x+w-1, y);

  uint8_t hi = color >> 8, lo = color;

  SPI_BEGIN_TRANSACTION();
  DC_HIGH();
  CS_LOW();

  while (w--) {
    spiwrite(hi);
    spiwrite(lo);
  }

  CS_HIGH();
  SPI_END_TRANSACTION();
}

void ST7789v_arduino::fillScreen(uint16_t color) {
  fillRect(0, 0,  _width, _height, color);
}

// // fill a rectangle
// void ST7789v_arduino::fillRect(int16_t x, int16_t y, int16_t w, int16_t h,
//   uint16_t color) {

//   // rudimentary clipping (drawChar w/big text requires this)
//   if((x >= _width) || (y >= _height)) return;
//   if((x + w - 1) >= _width)  w = _width  - x;
//   if((y + h - 1) >= _height) h = _height - y;

//   setAddrWindow(x, y, x+w-1, y+h-1);

//   uint8_t hi = color >> 8, lo = color;
    
//   SPI_BEGIN_TRANSACTION();

//   DC_HIGH();
//   CS_LOW();
//   for(y=h; y>0; y--) {
//     for(x=w; x>0; x--) {
//       spiwrite(hi);
//       spiwrite(lo);
//     }
//   }
//   CS_HIGH();
//   SPI_END_TRANSACTION();
// }

// fill a rectangle
void ST7789v_arduino::fillRect(int16_t x, int16_t y, int16_t w, int16_t h,
  uint16_t color) {

  // rudimentary clipping (drawChar w/big text requires this)
  if(x>=_width || y>=_height || w<=0 || h<=0) return;
  if(x+w-1>=_width)  w=_width -x;
  if(y+h-1>=_height) h=_height-y;
  setAddrWindow(x, y, x+w-1, y+h-1);

  uint8_t hi = color >> 8, lo = color;
    
  SPI_BEGIN_TRANSACTION();

  DC_HIGH();
  CS_LOW();
  
  uint32_t num = (uint32_t)w*h;
  uint16_t num16 = num>>4;
  while(num16--) {
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
    spiwrite(hi); spiwrite(lo);
  }
  uint8_t num8 = num & 0xf;
  while(num8--) { spiwrite(hi); spiwrite(lo); }


  CS_HIGH();
  SPI_END_TRANSACTION();
}

// Pass 8-bit (each) R,G,B, get back 16-bit packed color
uint16_t ST7789v_arduino::Color565(uint8_t r, uint8_t g, uint8_t b) {
  return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
}

void ST7789v_arduino::invertDisplay(boolean i) {
  writecommand(i ? ST7789_INVON : ST7789_INVOFF);
}

/******** low level bit twiddling **********/

inline void ST7789v_arduino::CS_HIGH(void) {
  if(_cs) {
    #if defined(USE_FAST_IO)
      *csport |= cspinmask;
    #else
    digitalWrite(_cs, HIGH);
    #endif
  }
}

inline void ST7789v_arduino::CS_LOW(void) {
  if(_cs) {
    #if defined(USE_FAST_IO)
    *csport &= ~cspinmask;
    #else
    digitalWrite(_cs, LOW);
    #endif
  }
}

inline void ST7789v_arduino::DC_HIGH(void) {
  _DCbit = true;
#if defined(USE_FAST_IO)
  *dcport |= dcpinmask;
#else
  digitalWrite(_dc, HIGH);
#endif
}

inline void ST7789v_arduino::DC_LOW(void) {
  _DCbit = false;
#if defined(USE_FAST_IO)
  *dcport &= ~dcpinmask;
#else
  digitalWrite(_dc, LOW);
#endif
}

void ST7789v_arduino::init(uint16_t width, uint16_t height) {
  commonInit(NULL);

  _colstart = ST7789_240x240_XSTART;
  _rowstart = ST7789_240x240_YSTART;
  _height = 320;
  _width = 240;

  displayInit(cmd_240x240);

  setRotation(2);
}

// ----------------------------------------------------------
// draws image from RAM
void ST7789v_arduino::drawImage(int16_t x, int16_t y, int16_t w, int16_t h, uint16_t *img16) 
{
  if(x>=_width || y>=_height || w<=0 || h<=0) return;
  setAddrWindow(x, y, x+w-1, y+h-1);

  SPI_BEGIN_TRANSACTION();

  DC_HIGH();
  CS_LOW();

  uint32_t num = (uint32_t)w*h;
  uint16_t num16 = num>>3;
  uint8_t *img = (uint8_t *)img16;
  while(num16--) {
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
    spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2;
  }
  uint8_t num8 = num & 0x7;
  while(num8--) { spiwrite(*(img+1)); spiwrite(*(img+0)); img+=2; }

  CS_HIGH();
  SPI_END_TRANSACTION();
}


// ----------------------------------------------------------
// draws image from flash (PROGMEM)
void ST7789v_arduino::drawImageF(int16_t x, int16_t y, int16_t w, int16_t h, const uint16_t *img16) 
{
  if(x>=_width || y>=_height || w<=0 || h<=0) return;
  setAddrWindow(x, y, x+w-1, y+h-1);

  SPI_BEGIN_TRANSACTION();

  DC_HIGH();
  CS_LOW();

  uint32_t num = (uint32_t)w*h;
  uint16_t num16 = num>>3;
  uint8_t *img = (uint8_t *)img16;
  while(num16--) {
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
    spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2;
  }
  uint8_t num8 = num & 0x7;
  while(num8--) { spiwrite(pgm_read_byte(img+1)); spiwrite(pgm_read_byte(img+0)); img+=2; }

  CS_HIGH();
  SPI_END_TRANSACTION();


}



// ----------------------------------------------------------
void ST7789v_arduino::partialDisplay(boolean mode) 
{
  writecommand(mode ? ST7789_PTLON : ST7789_NORON);
}

// ----------------------------------------------------------
void ST7789v_arduino::sleepDisplay(boolean mode) 
{
  writecommand(mode ? ST7789_SLPIN : ST7789_SLPOUT);
  delay(5);
}

// ----------------------------------------------------------
void ST7789v_arduino::enableDisplay(boolean mode) 
{
  writecommand(mode ? ST7789_DISPON : ST7789_DISPOFF);
}

// ----------------------------------------------------------
void ST7789v_arduino::idleDisplay(boolean mode) 
{
  writecommand(mode ? ST7789_IDMON : ST7789_IDMOFF);
}

// ----------------------------------------------------------
void ST7789v_arduino::resetDisplay() 
{
  writecommand(ST7789_SWRESET);
  delay(5);
}

// ----------------------------------------------------------
void ST7789v_arduino::setScrollArea(uint16_t tfa, uint16_t bfa) 
{
  uint16_t vsa = 240-tfa-bfa; // ST7789 320x240 VRAM
  writecommand(ST7789_VSCRDEF); // SETSCROLLAREA = 0x33
  writedata(tfa >> 8);
  writedata(tfa);
  writedata(vsa >> 8);
  writedata(vsa);
  writedata(bfa >> 8);
  writedata(bfa);
}

// ----------------------------------------------------------
void ST7789v_arduino::setScroll(uint16_t vsp) 
{
  writecommand(ST7789_VSCRSADD); // VSCRSADD = 0x37
  writedata(vsp >> 8);
  writedata(vsp);
}

// ----------------------------------------------------------
void ST7789v_arduino::setPartArea(uint16_t sr, uint16_t er) 
{
  writecommand(ST7789_PTLAR);  // SETPARTAREA = 0x30
  writedata(sr >> 8);
  writedata(sr);
  writedata(er >> 8);
  writedata(er);
}

// ----------------------------------------------------------
// doesn't work
void ST7789v_arduino::setBrightness(uint8_t br) 
{
  //writecommand(ST7789_WRCACE);
  //writedata(0xb1);  // 80,90,b0, or 00,01,02,03
  //writecommand(ST7789_WRCABCMB);
  //writedata(120);

  //BCTRL=0x20, dd=0x08, bl=0x04
  int val = 0x04;
  writecommand(ST7789_WRCTRLD);
  writedata(val);
  writecommand(ST7789_WRDISBV);
  writedata(br);
}

// ----------------------------------------------------------
// 0 - off
// 1 - idle
// 2 - normal
// 4 - display off
void ST7789v_arduino::powerSave(uint8_t mode) 
{
  if(mode==0) {
    writecommand(ST7789_POWSAVE);
    writedata(0xec|3);
    writecommand(ST7789_DLPOFFSAVE);
    writedata(0xff);
    return;
  }
  int is = (mode&1) ? 0 : 1;
  int ns = (mode&2) ? 0 : 2;
  writecommand(ST7789_POWSAVE);
  writedata(0xec|ns|is);
  if(mode&4) {
    writecommand(ST7789_DLPOFFSAVE);
    writedata(0xfe);
  }
}

// ------------------------------------------------
// Input a value 0 to 511 (85*6) to get a color value.
// The colours are a transition R - Y - G - C - B - M - R.
void ST7789v_arduino::rgbWheel(int idx, uint8_t *_r, uint8_t *_g, uint8_t *_b)
{
  idx &= 0x1ff;
  if(idx < 85) { // R->Y  
    *_r = 255; *_g = idx * 3; *_b = 0;
    return;
  } else if(idx < 85*2) { // Y->G
    idx -= 85*1;
    *_r = 255 - idx * 3; *_g = 255; *_b = 0;
    return;
  } else if(idx < 85*3) { // G->C
    idx -= 85*2;
    *_r = 0; *_g = 255; *_b = idx * 3;
    return;  
  } else if(idx < 85*4) { // C->B
    idx -= 85*3;
    *_r = 0; *_g = 255 - idx * 3; *_b = 255;
    return;    
  } else if(idx < 85*5) { // B->M
    idx -= 85*4;
    *_r = idx * 3; *_g = 0; *_b = 255;
    return;    
  } else { // M->R
    idx -= 85*5;
    *_r = 255; *_g = 0; *_b = 255 - idx * 3;
   return;
  }
} 

uint16_t ST7789v_arduino::rgbWheel(int idx)
{
  uint8_t r,g,b;
  rgbWheel(idx, &r,&g,&b);
  return RGBto565(r,g,b);
}

void ST7789v_arduino::startWrite(void){

  SPI_BEGIN_TRANSACTION();
  CS_LOW();
}

void ST7789v_arduino::endWrite(void){
  CS_HIGH();
  SPI_END_TRANSACTION();
}