zGxEPD2/src/epd/GxEPD2_270.cpp

// Display Library for SPI e-paper panels from Dalian Good Display and boards from Waveshare.
// Requires HW SPI and Adafruit_GFX. Caution: these e-papers require 3.3V supply AND data lines!
//
// based on Demo Example from Good Display: http://www.e-paper-display.com/download_list/downloadcategoryid=34&isMode=false.html
// Controller: IL91874 : http://www.e-paper-display.com/download_detail/downloadsId=539.html
//
// Author: Jean-Marc Zingg
//
// Version: see library.properties
//
// Library: https://github.com/ZinggJM/GxEPD2

#include "GxEPD2_270.h"

GxEPD2_270::GxEPD2_270(int8_t cs, int8_t dc, int8_t rst, int8_t busy) :
  GxEPD2_EPD(cs, dc, rst, busy, LOW, 10000000, WIDTH, HEIGHT, panel, hasColor, hasPartialUpdate, hasFastPartialUpdate)
{
}

void GxEPD2_270::clearScreen(uint8_t value)
{
  if (_initial)
  {
    _Init_Full();
    _writeCommand(0x10); // preset previous
    for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
    {
      _writeData(0xFF); // 0xFF is white
    }
    _writeCommand(0x13); // set current
    for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
    {
      _writeData(value);
    }
    _Update_Full();
    _initial = false;
  }
  if (!_using_partial_mode) _Init_Part();
  _setPartialRamArea(0x15, 0, 0, WIDTH, HEIGHT);
  for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
  {
    _writeData(value);
  }
  _refreshWindow(0, 0, WIDTH, HEIGHT);
  _waitWhileBusy("clearScreen", partial_refresh_time);
  _setPartialRamArea(0x14, 0, 0, WIDTH, HEIGHT);
  for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
  {
    _writeData(value);
  }
}

void GxEPD2_270::writeScreenBuffer(uint8_t value)
{
  if (_initial) clearScreen(value);
  else _writeScreenBuffer(value);
}

void GxEPD2_270::_writeScreenBuffer(uint8_t value)
{
  _Init_Part();
  _setPartialRamArea(0x15, 0, 0, WIDTH, HEIGHT);
  for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
  {
    _writeData(value);
  }
}

void GxEPD2_270::writeScreenBufferAgain(uint8_t value)
{
  _Init_Part();
  _setPartialRamArea(0x14, 0, 0, WIDTH, HEIGHT);
  for (uint32_t i = 0; i < uint32_t(WIDTH) * uint32_t(HEIGHT) / 8; i++)
  {
    _writeData(value);
  }
}

void GxEPD2_270::writeImage(const uint8_t bitmap[], int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  _writeImage(0x15, bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::writeImageAgain(const uint8_t bitmap[], int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  _writeImage(0x14, bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::_writeImage(uint8_t command, const uint8_t bitmap[], int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  delay(1); // yield() to avoid WDT on ESP8266 and ESP32
  int16_t wb = (w + 7) / 8; // width bytes, bitmaps are padded
  x -= x % 8; // byte boundary
  w = wb * 8; // byte boundary
  int16_t x1 = x < 0 ? 0 : x; // limit
  int16_t y1 = y < 0 ? 0 : y; // limit
  int16_t w1 = x + w < int16_t(WIDTH) ? w : int16_t(WIDTH) - x; // limit
  int16_t h1 = y + h < int16_t(HEIGHT) ? h : int16_t(HEIGHT) - y; // limit
  int16_t dx = x1 - x;
  int16_t dy = y1 - y;
  w1 -= dx;
  h1 -= dy;
  if ((w1 <= 0) || (h1 <= 0)) return;
  if (!_using_partial_mode) _Init_Part();
  _setPartialRamArea(command, x1, y1, w1, h1);
  for (int16_t i = 0; i < h1; i++)
  {
    for (int16_t j = 0; j < w1 / 8; j++)
    {
      uint8_t data;
      // use wb, h of bitmap for index!
      int16_t idx = mirror_y ? j + dx / 8 + ((h - 1 - (i + dy))) * wb : j + dx / 8 + (i + dy) * wb;
      if (pgm)
      {
#if defined(__AVR) || defined(ESP8266) || defined(ESP32)
        data = pgm_read_byte(&bitmap[idx]);
#else
        data = bitmap[idx];
#endif
      }
      else
      {
        data = bitmap[idx];
      }
      if (invert) data = ~data;
      _writeData(data);
    }
  }
  delay(1); // yield() to avoid WDT on ESP8266 and ESP32
}

void GxEPD2_270::writeImagePart(const uint8_t bitmap[], int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
                                    int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  _writeImagePart(0x15, bitmap, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::writeImagePartAgain(const uint8_t bitmap[], int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
    int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  _writeImagePart(0x14, bitmap, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::_writeImagePart(uint8_t command, const uint8_t bitmap[], int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
                                int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  delay(1); // yield() to avoid WDT on ESP8266 and ESP32
  if ((w_bitmap < 0) || (h_bitmap < 0) || (w < 0) || (h < 0)) return;
  if ((x_part < 0) || (x_part >= w_bitmap)) return;
  if ((y_part < 0) || (y_part >= h_bitmap)) return;
  int16_t wb_bitmap = (w_bitmap + 7) / 8; // width bytes, bitmaps are padded
  x_part -= x_part % 8; // byte boundary
  w = w_bitmap - x_part < w ? w_bitmap - x_part : w; // limit
  h = h_bitmap - y_part < h ? h_bitmap - y_part : h; // limit
  x -= x % 8; // byte boundary
  w = 8 * ((w + 7) / 8); // byte boundary, bitmaps are padded
  int16_t x1 = x < 0 ? 0 : x; // limit
  int16_t y1 = y < 0 ? 0 : y; // limit
  int16_t w1 = x + w < int16_t(WIDTH) ? w : int16_t(WIDTH) - x; // limit
  int16_t h1 = y + h < int16_t(HEIGHT) ? h : int16_t(HEIGHT) - y; // limit
  int16_t dx = x1 - x;
  int16_t dy = y1 - y;
  w1 -= dx;
  h1 -= dy;
  if ((w1 <= 0) || (h1 <= 0)) return;
  if (!_using_partial_mode) _Init_Part();
  _setPartialRamArea(command, x1, y1, w1, h1);
  for (int16_t i = 0; i < h1; i++)
  {
    for (int16_t j = 0; j < w1 / 8; j++)
    {
      uint8_t data;
      // use wb_bitmap, h_bitmap of bitmap for index!
      int16_t idx = mirror_y ? x_part / 8 + j + dx / 8 + ((h_bitmap - 1 - (y_part + i + dy))) * wb_bitmap : x_part / 8 + j + dx / 8 + (y_part + i + dy) * wb_bitmap;
      if (pgm)
      {
#if defined(__AVR) || defined(ESP8266) || defined(ESP32)
        data = pgm_read_byte(&bitmap[idx]);
#else
        data = bitmap[idx];
#endif
      }
      else
      {
        data = bitmap[idx];
      }
      if (invert) data = ~data;
      _writeData(data);
    }
  }
  delay(1); // yield() to avoid WDT on ESP8266 and ESP32
}

void GxEPD2_270::writeImage(const uint8_t* black, const uint8_t* color, int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (black)
  {
    writeImage(black, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::writeImagePart(const uint8_t* black, const uint8_t* color, int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
                                int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (black)
  {
    writeImagePart(black, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::writeNative(const uint8_t* data1, const uint8_t* data2, int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (data1)
  {
    writeImage(data1, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::drawImage(const uint8_t bitmap[], int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  writeImage(bitmap, x, y, w, h, invert, mirror_y, pgm);
  refresh(x, y, w, h);
  writeImageAgain(bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::drawImagePart(const uint8_t bitmap[], int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
                               int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  writeImagePart(bitmap, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
  refresh(x, y, w, h);
  writeImagePartAgain(bitmap, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
}

void GxEPD2_270::drawImage(const uint8_t* black, const uint8_t* color, int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (black)
  {
    drawImage(black, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::drawImagePart(const uint8_t* black, const uint8_t* color, int16_t x_part, int16_t y_part, int16_t w_bitmap, int16_t h_bitmap,
                               int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (black)
  {
    drawImagePart(black, x_part, y_part, w_bitmap, h_bitmap, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::drawNative(const uint8_t* data1, const uint8_t* data2, int16_t x, int16_t y, int16_t w, int16_t h, bool invert, bool mirror_y, bool pgm)
{
  if (data1)
  {
    drawImage(data1, x, y, w, h, invert, mirror_y, pgm);
  }
}

void GxEPD2_270::refresh(bool partial_update_mode)
{
  if (partial_update_mode) refresh(0, 0, WIDTH, HEIGHT);
  else
  {
    if (_using_partial_mode) _Init_Full();
    _Update_Full();
  }
}

void GxEPD2_270::refresh(int16_t x, int16_t y, int16_t w, int16_t h)
{
  x -= x % 8; // byte boundary
  w -= x % 8; // byte boundary
  int16_t x1 = x < 0 ? 0 : x; // limit
  int16_t y1 = y < 0 ? 0 : y; // limit
  int16_t w1 = x + w < int16_t(WIDTH) ? w : int16_t(WIDTH) - x; // limit
  int16_t h1 = y + h < int16_t(HEIGHT) ? h : int16_t(HEIGHT) - y; // limit
  w1 -= x1 - x;
  h1 -= y1 - y;
  _refreshWindow(x1, y1, w1, h1);
  _waitWhileBusy("refresh", partial_refresh_time);
}

void GxEPD2_270::powerOff(void)
{
  _PowerOff();
}

void GxEPD2_270::hibernate()
{
  _PowerOff();
  if (_rst >= 0)
  {
    _writeCommand(0x07); // deep sleep
    _writeData(0xA5);    // check code
    _hibernating = true;
  }
}

void GxEPD2_270::_setPartialRamArea(uint8_t command, uint16_t x, uint16_t y, uint16_t w, uint16_t h)
{
  w = (w + 7 + (x % 8)) & 0xfff8; // byte boundary exclusive (round up)
  _writeCommand(command);
  _writeData(x >> 8);
  _writeData(x & 0xf8);
  _writeData(y >> 8);
  _writeData(y & 0xff);
  _writeData(w >> 8);
  _writeData(w & 0xf8);
  _writeData(h >> 8);
  _writeData(h & 0xff);
}

void GxEPD2_270::_refreshWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h)
{
  w = (w + 7 + (x % 8)) & 0xfff8; // byte boundary exclusive (round up)
  h = gx_uint16_min(h, 256); // strange controller error
  _writeCommand(0x16);
  _writeData(x >> 8);
  _writeData(x & 0xf8);
  _writeData(y >> 8);
  _writeData(y & 0xff);
  _writeData(w >> 8);
  _writeData(w & 0xf8);
  _writeData(h >> 8);
  _writeData(h & 0xff);
}

void GxEPD2_270::_PowerOn()
{
  if (!_power_is_on)
  {
    _writeCommand(0x04);
    _waitWhileBusy("_PowerOn", power_on_time);
  }
  _power_is_on = true;
}

void GxEPD2_270::_PowerOff()
{
  _writeCommand(0x02); // power off
  _waitWhileBusy("_PowerOff", power_off_time);
  _power_is_on = false;
  _using_partial_mode = false;
}

void GxEPD2_270::_InitDisplay()
{
  if (_hibernating) _reset();
  _writeCommand(0x01); //POWER SETTING
  _writeData (0x03);
  _writeData (0x00);
  _writeData (0x2b);
  _writeData (0x2b);
  _writeCommand(0x06); //boost
  _writeData (0x07);   //A
  _writeData (0x07);   //B
  _writeData (0x17);   //C
  _writeCommand(0x16);
  _writeData(0x00);
  //_writeCommand(0x04);
  //_waitWhileBusy("_wakeUp Power On");
  _writeCommand(0x00); //panel setting
  _writeData(0xbf);    //KW-BF   KWR-AF  BWROTP 0f
  _writeCommand(0x30); //PLL setting
  _writeData (0x3a);   //90 50HZ  3A 100HZ   29 150Hz 39 200HZ 31 171HZ
  _writeCommand(0x61); //resolution setting
  _writeData (0x00);
  _writeData (0xb0); //176
  _writeData (0x01);
  _writeData (0x08); //264
  _writeCommand(0x82); //vcom_DC setting
  _writeData (0x08);   //0x28:-2.0V,0x12:-0.9V
}

//full screen update LUT
const uint8_t GxEPD2_270::lut_20_vcomDC[] PROGMEM =
{
  0x00, 0x00,
  0x00, 0x08, 0x00, 0x00, 0x00, 0x02,
  0x60, 0x28, 0x28, 0x00, 0x00, 0x01,
  0x00, 0x14, 0x00, 0x00, 0x00, 0x01,
  0x00, 0x12, 0x12, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_21_ww[] PROGMEM =
{
  0x40, 0x08, 0x00, 0x00, 0x00, 0x02,
  0x90, 0x28, 0x28, 0x00, 0x00, 0x01,
  0x40, 0x14, 0x00, 0x00, 0x00, 0x01,
  0xA0, 0x12, 0x12, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_22_bw[] PROGMEM =
{
  0x40, 0x08, 0x00, 0x00, 0x00, 0x02,
  0x90, 0x28, 0x28, 0x00, 0x00, 0x01,
  0x40, 0x14, 0x00, 0x00, 0x00, 0x01,
  0xA0, 0x12, 0x12, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_23_wb[] PROGMEM =
{
  0x80, 0x08, 0x00, 0x00, 0x00, 0x02,
  0x90, 0x28, 0x28, 0x00, 0x00, 0x01,
  0x80, 0x14, 0x00, 0x00, 0x00, 0x01,
  0x50, 0x12, 0x12, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_24_bb[] PROGMEM =
{
  0x80, 0x08, 0x00, 0x00, 0x00, 0x02,
  0x90, 0x28, 0x28, 0x00, 0x00, 0x01,
  0x80, 0x14, 0x00, 0x00, 0x00, 0x01,
  0x50, 0x12, 0x12, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

//partial screen update LUT
const uint8_t GxEPD2_270::lut_20_vcomDC_partial[] PROGMEM =
{
  0x00, 0x00,
  0x00, 0x19, 0x01, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_21_ww_partial[] PROGMEM =
{
  0x00, 0x19, 0x01, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_22_bw_partial[] PROGMEM =
{
  0x80, 0x19, 0x01, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_23_wb_partial[] PROGMEM =
{
  0x40, 0x19, 0x01, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t GxEPD2_270::lut_24_bb_partial[] PROGMEM =
{
  0x00, 0x19, 0x01, 0x00, 0x00, 0x01,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

void GxEPD2_270::_Init_Full()
{
  _InitDisplay();
  _writeCommand(0x50); //VCOM AND DATA INTERVAL SETTING
  _writeData(0x97);    //WBmode:VBDF 17|D7 VBDW 97 VBDB 57   WBRmode:VBDF F7 VBDW 77 VBDB 37  VBDR B7
  _writeCommand(0x20);
  _writeDataPGM(lut_20_vcomDC, sizeof(lut_20_vcomDC));
  _writeCommand(0x21);
  _writeDataPGM(lut_21_ww, sizeof(lut_21_ww));
  _writeCommand(0x22);
  _writeDataPGM(lut_22_bw, sizeof(lut_22_bw));
  _writeCommand(0x23);
  _writeDataPGM(lut_23_wb, sizeof(lut_23_wb));
  _writeCommand(0x24);
  _writeDataPGM(lut_24_bb, sizeof(lut_24_bb));
  _PowerOn();
  _using_partial_mode = false;
}

void GxEPD2_270::_Init_Part()
{
  _InitDisplay();
  _writeCommand(0x50); //VCOM AND DATA INTERVAL SETTING
  _writeData(0x17);    //WBmode:VBDF 17|D7 VBDW 97 VBDB 57   WBRmode:VBDF F7 VBDW 77 VBDB 37  VBDR B7
  _writeCommand(0x20);
  _writeDataPGM(lut_20_vcomDC_partial, sizeof(lut_20_vcomDC_partial));
  _writeCommand(0x21);
  _writeDataPGM(lut_21_ww_partial, sizeof(lut_21_ww_partial));
  _writeCommand(0x22);
  _writeDataPGM(lut_22_bw_partial, sizeof(lut_22_bw_partial));
  _writeCommand(0x23);
  _writeDataPGM(lut_23_wb_partial, sizeof(lut_23_wb_partial));
  _writeCommand(0x24);
  _writeDataPGM(lut_24_bb_partial, sizeof(lut_24_bb_partial));
  _PowerOn();
  _using_partial_mode = true;
}

void GxEPD2_270::_Update_Full()
{
  _writeCommand(0x12); //display refresh
  _waitWhileBusy("_Update_Full", full_refresh_time);
}

void GxEPD2_270::_Update_Part()
{
  _writeCommand(0x12); //display refresh
  _waitWhileBusy("_Update_Part", partial_refresh_time);
}

void GxEPD2_270::_writeDataPGM(const uint8_t* data, uint16_t n)
{
  SPI.beginTransaction(_spi_settings);
  for (uint8_t i = 0; i < n; i++)
  {
    if (_cs >= 0) digitalWrite(_cs, LOW);
    SPI.transfer(pgm_read_byte(&*data++));
    if (_cs >= 0) digitalWrite(_cs, HIGH);
  }
  SPI.endTransaction();
}