GxEPD2

Arduino Display Library for SPI E-Paper Displays

• With full Graphics and Text support using Adafruit_GFX

• For SPI e-paper displays from Dalian Good Display

• and SPI e-paper boards from Waveshare

important note:

• the display panels are for 3.3V supply and 3.3V data lines
• never connect data lines directly to 5V Arduino data pins, use e.g. 4k7/10k resistor divider
• series resistor only is not enough for reliable operation (back-feed effect through protection diodes)
• 4k7/10k resistor divider may not work with flat cable extensions or Waveshare 4.2 board, use level converter then
• do not forget to connect GND
• the actual Waveshare display boards now have level converters and series regulator, safe for 5V
• use 3k3 pull-down on SS for ESP8266 for boards with level converters
• note that 7.5" e-paper displays don't work reliable if fed from 3.3V Arduino pin
• note that Waveshare boards with "clever" reset circuit may need shortened reset pulse
• use init(115200, true, 2, false) for Waveshare boards with "clever" reset circuit
• note that Waveshare boards with "clever" reset circuit need 1k pull-up on RST on ESP8266, or different pin

Paged Drawing, Picture Loop

• This library uses paged drawing to limit RAM use and cope with missing single pixel update support
• buffer size can be selected in the application by template parameter page_height, see GxEPD2_Example
• Paged drawing is implemented as picture loop, like in U8G2 (Oliver Kraus)
• see https://github.com/olikraus/u8glib/wiki/tpictureloop
• Paged drawing is also available using drawPaged() and drawCallback(), like in GxEPD
• // GxEPD style paged drawing; drawCallback() is called as many times as needed
• void drawPaged(void (*drawCallback)(const void*), const void* pv)
• paged drawing is done using Adafruit_GFX methods inside picture loop or drawCallback

Full Screen Buffer Support

• full screen buffer is selected by setting template parameter page_height to display height
• drawing to full screen buffer is done using Adafruit_GFX methods without picture loop or drawCallback
• and then calling method display()

Low Level Bitmap Drawing Support

• bitmap drawing support to the controller memory and screen is available:
• either through the template class instance methods that forward calls to the base display class
• or directly using an instance of a base display class and calling its methods directly

Supporting Arduino Forum Topics:

• Waveshare e-paper displays with SPI: http://forum.arduino.cc/index.php?topic=487007.0
• Good Display ePaper for Arduino : https://forum.arduino.cc/index.php?topic=436411.0

Note on documentation

• GxEPD2 uses Adafruit_GFX for Graphics and Text support, which is well documented there
• GxEPD2 uses meaningful method names, and has some comments in the header files
• consult the header files GxEPD2_BW.h, GxEPD2_3C.h and GxEPD2_GFX.h
• for the concept of paged drawing and picture loop see:
• https://github.com/olikraus/u8glib/wiki/tpictureloop

Supported SPI e-paper panels from Good Display:

• GDEW0102T4 1.02" b/w 80x128, UC8175
• DEPG0150BN 1.50" b/w 200x200, SSD1681, e.g. LILYGO® TTGO T5 V2.4.1 1.50 inch
• GDEP015OC1 1.54" b/w 200x200, IL3829, no longer available
• GDEH0154D67 1.54" b/w 200x200, SSD1681, replacement for GDEP015OC1
• GDEW0154T8 1.54" b/w 152x152, UC8151 (IL0373)
• GDEW0154M09 1.54" b/w 200x200, JD79653A
• GDEW0154M10 1.54" b/w 152x152, UC8151D, DES
• GDEY0154D67 1.54" b/w 200x200, SSD1681
• GDEW0154Z04 1.54" b/w/r 200x200, IL0376F, no longer available
• GDEH0154Z90 1.54" b/w/r 200x200, SSD1681, replacement for GDEW0154Z04
• GDE0213B1 2.13" b/w 122x250, IL3895, phased out
• GDEH0213B72 2.13" b/w 122x250, SSD1675A (IL3897), replacement for GDE0213B1
• GDEH0213B73 2.13" b/w 122x250, SSD1675B, new replacement for GDE0213B1, GDEH0213B72
• GDEM0213B74 2.13" b/w 122x250, SSD1680
• GDEW0213I5F 2.13" b/w 104x212, UC8151 (IL0373), flexible
• GDEW0213T5D 2.13" b/w 104x212, UC8151 (IL0373)
• GDEW0213M21 2.13" b/w 104x212, UC8151 (IL0373), DES
• GDEW0213Z16 2.13" b/w/r 104x212, UC8151 (IL0373)
• GDEW0213Z19 2.13" b/w/r 104x212, UC8151D
• GDEY0213Z98 2.13" b/w/r 122x250, SSD1680
• DEPG0213BN 2.13" b/w 122x250, SSD1680, e.g. LILYGO® TTGO T5 V2.3.1 2.13 inch
• GDEY0213B74 2.13" b/w 122x250, SSD1680
• GDEW026T0 2.6" b/w 152x296, UC8151 (IL0373)
• GDEW026M01 2.6" b/w 152x296, UC8151 (IL0373), DES
• DEPG0266BN 2.66" b/w 152x296, SSD1680, e.g. LILYGO® TTGO T5 2.66 inch
• GDEY0266Z90 2.66" b/w/r 152x296, SSD1680
• GDEW027C44 2.7" b/w/r 176x264, IL91874
• GDEW027W3 2.7" b/w 176x264, EK79652 (IL91874)
• GDEY027T91 2.7" b/w 176x264, SSD1680
• GDEH029A1 2.9" b/w 128x296, SSD1608 (IL3820)
• GDEW029T5 2.9" b/w 128x296, UC8151 (IL0373)
• GDEW029T5D 2.9" b/w 128x296, UC8151D
• GDEW029I6FD 2.9" b/w 128x296, UC8151D, flexible
• GDEM029T94 2.9" b/w 128x296, SSD1680
• GDEW029M06 2.9" b/w 128x296, UC8151D, DES
• GDEW029Z10 2.9" b/w/r 128x296, UC8151 (IL0373)
• GDEH029Z13 2.9" b/w/r 128x296, UC8151D
• GDEM029C90 2.9" b/w/y 128x296, SSD1680
• DEPG0290BS 2.9" b/w 128x296, SSD1680, e.g. LILYGO® TTGO T5 V2.4.1 2.9"
• GDEY029T94 2.9" b/w 128x296, SSD1680
• ED037TC1 3.7" b/w 280x480, SSD1677, Waveshare 3.7"
• GDEW0371W7 3.7" b/w 240x416, UC8171 (IL0324)
• GDEW042T2 4.2" b/w 400x300, UC8176 (IL0398)
• GDEW042M01 4.2" b/w 400x300, UC8176 (IL0398), DES
• GDEW042Z15 4.2" b/w/r 400x300, UC8176 (IL0398)
• GDEQ042Z21 4.2" b/w/r 400x300, UC8276, (Waveshare V2)
• GDEY042T91 4.2" b/w 400x300, SSD1683
• Waveshare437inch4color Waveshare 4.37" 4-color e-paper display 512x368
• ACeP565 5.65" Waveshare 5.65" 7-color e-paper display 600x448
• GDEW0583T7 5.83" b/w 600x448, UC8159c (IL0371)
• GDEW0583T8 5.83" b/w 648x480, EK79655 (GD7965)
• GDEW0583Z83 5.83" b/w/r 648x480, EK79655 (GD7965)
• GDEQ0583T31 5.83" b/w 648x480, UC8179
• GDEY073D46 7.3" 800x480 7-color
• GDEW075T8 7.5" b/w 640x384, UC8159c (IL0371)
• GDEW075T7 7.5" b/w 800x480, EK79655 (GD7965)
• GDEY075T7 7.5" b/w 800x480, UC8179 (GD7965)
• GDEW075Z09 7.5" b/w/r 640x384, UC8159c (IL0371)
• GDEW075Z08 7.5" b/w/r 800x480, EK79655 (GD7965)
• GDEH075Z90 7.5" b/w/r 880x528, SSD1677
• GDEH116T91 11.6" b/w 960x640, SSD1677
• GDEW1248T3 12.48" b/w 1304x984, UC8179
• GDEY1248Z51 12.48" b/w/r 1304x984, UC8179

Supported SPI e-paper panels & boards from Waveshare: compare with Good Display, same panel

other supported panels

• ED060SCT 6" grey levels, on Waveshare e-Paper IT8951 Driver HAT
• ED060KC1 6" grey levels, 1448x1072, on Waveshare e-Paper IT8951 Driver HAT
• ED078KC2 7.8" grey levels, 1872x1404, on Waveshare e-Paper IT8951 Driver HAT
• ES103TC1 10.3" grey levels, 1872x1404, on Waveshare e-Paper IT8951 Driver HAT

I can and will only support e-paper panels I have!

• promotion panels from suppliers are welcome, to add support to GxEPD2
• donation panels from users are welcome, to add support to GxEPD2

Version 1.5.2

• added support for Waveshare 4.37" 4-color e-paper display 512x368
• fixed __has_include test (for packages that don't support __has_include)
• added WIDTH_VISIBLE for correct graphics width for 2.13" b/w 122x250
• added end() method, to release SPI and reset all pins to INPUT

Version 1.5.1

• added support for GDEY0154D67 1.54" b/w 200x200
• added support for GDEY0213B74 2.13" b/w 128x250
• updated support for GDEY027T91 2.7" b/w 176x264
• renamed driver class for GDEY027T91 to GxEPD2_270_GDEY027T91
• added support for GDEY029T94 2.9" b/w 128x296
• added support for GDEY042T91 4.2" b/w 400x300
• added support for GDEQ0583T31 5.83" b/w 648x480
• these panels have fast full refresh capability
• fast full refresh can be disabled in the class header for low temperature use
• added support for GDEY073D46 7.3" 800x480 7-color
• all these new panels have been donated by Good Display
• added __has_include test to GxEPD2_BW.h, GxEPD2_3C.h, GxEPD2_7C
• this allows to remove or put aside unused driver classes for faster compile
• several fixes and improvements

Version 1.5.0

• added support for GDEY075T7 7.5" b/w 800x480
• updated GxEPD2_Example, added HSPI use for Waveshare ESP32 Driver Board
• updated GxEPD2_SD_AVR_Example, fixes for BMP handling
• updated GxEPD2_SD_Example, fixes for BMP handling, added HSPI use for Waveshare ESP32 Driver Board
• updated GxEPD2_SerialFlash_Example, fixes for BMP handling
• updated GxEPD2_SerialFlash_Loader, updated https certificates and use
• updated GxEPD2_Spiffs_Example, fixes for BMP handling
• updated GxEPD2_Spiffs_Loader, updated https certificates and use
• added GxEPD2_WiFi_CertStore_Example, use of a BearSSL CertStore on ESP8266, like a browser
• added GxEPD2_WiFi_CertStore_Loader, download root certificates (from Mozilla) to ESP8266 flash
• updated GxEPD2_WiFi_Example, fixes for BMP handling, updated https certificates and use
• updated GxEPD2_WS_ESP32_Driver, added HSPI use for Waveshare ESP32 Driver Board

Version 1.4.9

• added missing constructor lines to GxEPD2_display_selection.h
• added panel details to comments in GxEPD2_display_selection.h
• added panel details to Supported SPI e-paper panels in README.md

Version 1.4.8

• added support for GDEY027T91 2.7" b/w 176x264
• added support for GDEY1248Z51 12.48" b/w/r 1304x984
• fixed name of panel DEPG0150BN
• updated certificate and fingerprint for GitHub download in GxEPD2_WiFi_Example

Version 1.4.7

• added support for DEPG0150BN 1.50" b/w 200x200, e.g. LILYGO® TTGO T5 V2.4.1 1.50 inch
• added support for DEPG0213BN 2.13" b/w 128x250, e.g. LILYGO® TTGO T5 V2.3.1 2.13 inch
• added support for DEPG0266BN 2.66" b/w 152x296, e.g. LILYGO® TTGO T5 2.66 inch
• added support for DEPG0290BS 2.9" b/w 128x296, e.g. LILYGO® TTGO T5 V2.4.1 2.9"
• added support for ES103TC1 10.3" grey levels, 1872x1404, on Waveshare e-Paper IT8951 Driver HAT

Version 1.4.6

• added support for GDEY0266Z90 2.66" b/w/r 152x296
• added support for GDEW0583Z83 5.83" b/w/r 648x460

Version 1.4.5

• added support for GDEY0213Z98 2.13" b/w/r 122x250
• tested with LOLIN 2.13" Tri-Color eInk / ePaper 250x122 Display Shield
• https://www.aliexpress.com/item/1005003020667903.html

Version 1.4.4

• interim update to solve compiler warnings (ALL for GCC for AVR)

Version 1.4.3

• added option to select an alternate HW SPI channel and/or SPI settings
• by method selectSPI(SPIClass& spi, SPISettings spi_settings) of driver base class GxEPD2_EPD
• by calling selectSPI before calling init() of display class
• or by calling extended init() method that has these parameters added
• tested with RPi Pico RP2040 using Good Display DESPI-PICO connection shield
• updated GxEPD2_Example to show use with DESPI-PICO
• DESPI-PICO: see https://www.good-display.com/product/393.html

Version 1.4.2

• added support for Waveshare 3.7" b/w board and panel ED037TC1
• waveform tables for ED037TC1 are taken unmodified from Waveshare demo code
• refresh behavior with ED037TC1 with GxEPD2 is not perfect, could not be resolved
• ISSUE RESOLVED: RESE needs to be 3 ohms on DESPI-C02 for this panel, Waveshare schematics is wrong
• added differential refresh for GDEH116T91, waveform table taken from ED037TC1
• differential refresh for GDEH116T91 looks ok; can be disabled with hasFastPartialUpdate = false
• increased sustain phase for differential refresh on GDEW042T2

Version 1.4.1

• fix for Waveshare "clever" reset circuit: power controller before reset pulse

Version 1.4.0

• changed the default reset duration to 10ms instead of 20ms
• changed the delay after reset to 10ms or reset duration, whichever is higher, instead of 200ms
• added a busyCallback feature, to allow to service periodic actions during wait for BUSY termination
• // register a callback function to be called during _waitWhileBusy continuously.
• void setBusyCallback(void (*busyCallback)(const void*), const void* busy_callback_parameter = 0);
• added example GxEPD2_RotaryUsingBusyCallback.ino

Version 1.3.9

• fix for STM32 official package pin number range (int16_t)
• fix for refresh(int16_t x, int16_t y, int16_t w, int16_t h) methods screen intersection

Version 1.3.8

• added support for GDEQ042Z21 4.2" b/w/r 400x300 panel or Waveshare 4.2" V2 b/w/r board
• the Waveshare 4.2" V2 b/w/r board requires the shortened reset pulse
• added support for GDEW029I6FD 2.9" b/w 128x296 flexible board
• some fixes and improvement for the new style panel selection

Version 1.3.7

• added support for GDEW0102T4 1.02" b/w 80x128 panel or Waveshare 1.02" b/w board
• the GDEW0102T4 panel has a different connector than the other SPI panels
• the GDEW0102T4 panel can be used with the DESPI-C102 connection module
• https://buy-lcd.com/products/connection-board-demo-kit-for-102-inch-e-ink-display-despi-c102
• my test have been done with the Waveshare 1.02" b/w board

Version 1.3.6

• added support for Waveshare 2.9" b/w V2, driver class GxEPD2_290_T94_V2
• Waveshare 2.9" b/w V2 uses a GDEM029T94 variant without partial update wft in OTP
• driver class GxEPD2_290_T94_V2 uses partial update wft written to registers
• added NOTE for RST pull-up on ESP8266 with "clever" reset circuit, or alternate pin

Version 1.3.5

• added support for GDEM0213B74 122x250 b/w e-paper panel
• added support for ED078KC2, 7.8" grey levels, 1872x1404, on Waveshare e-Paper IT8951 Driver HAT

Version 1.3.4

• added support for GDEH116T91 960x640 b/w e-paper panel
• GDEH116T91 has only full screen refresh, no wavetable for differential refresh yet
• added support for processor Arduino Nano RP2040 Connect to the examples
• added general fast b/w refresh for capable 3-color displays GDEW0213Z19, GDEW029Z13
• added example GxEPD2x_FastBlackWhiteOnColor.ino for GDEW0213Z19, GDEW029Z13
• evaluation of other fast b/w capable 3-color panels may follow

Version 1.3.3

• added b/w differential refresh method to GDEW0213Z19
• added b/w differential refresh method to GDEW029Z13
• up to 100 b/w fast refreshes have been possible (resulting in slightly reddish background)
• added experimental example GxEPD2x_MixedTest for proof of concept
• GxEPD2x_MixedTest needs enough RAM for 2 GFXCanvas1 objects
• general 3-color mixed refresh in GxEPD2 is in evaluation, for capable panels

Version 1.3.2

• added support for GDEW0213T5D 104x212 b/w e-paper panel
• added support for GDEW029T5D 128x296 b/w e-paper panel
• added support for GDEW0213Z19 104x212 b/w/r e-paper panel
• added support for GDEW029Z13 128x296 b/w/r e-paper panel
• both GDEW0213Z19 and GDEW029Z13 support only full screen refresh (controller issue)

Version 1.3.1

• added support for GDEM029C90 128x296 b/w/y e-paper panel
• GDEM029C90 has a very long refresh time of about 27 seconds
• GDEM029C90 has partial update (window addressing) of controller memory
• GDEM029C90 supports only full refresh of screen

Version 1.3.0

• added support for GDEM029T94 128x296 b/w e-paper panel
• added support for GDEW026M01 152x296 b/w new DES e-paper panel
• the new GDEW026M01 DES b/w e-paper panel has higher contrast and wide temperature range
• differential refresh (fast partial update) is supported for normal temperature range
• disable differential refresh for extended temperatures by setting hasFastPartialUpdate = false;
• the differential waveform table for GDEW026M01 is experimental and may need improvement
• major update of display selection in the examples to make additions easier:
• old style selection is now in separate include files GxEPD2_display_selection.h
• and GxEPD2_display_selection_added.h
• added new style display selection in include file GxEPD2_display_selection_new_style.h
• either selection style can be used. old style is intended for easy copying of constructor lines.

Version 1.2.16

• fix for GDEH0154D67, to work independent of OTP version (ping-pong issue)

Version 1.2.15

• added support for GDEW0213M21 2.13" 104x212 b/w new DES e-paper panel
• added support for GDEW029M06 2.9" 128x296 b/w new DES e-paper panel
• added support for GDEW042M01 4.2" 400x300 b/w new DES e-paper panel
• these new DES b/w e-paper panels have higher contrast and wide temperature range
• differential refresh (fast partial update) is supported for normal temperature range
• disable differential refresh for extended temperatures by setting hasFastPartialUpdate = false;
• the GDEW042M01 I have is a preliminary version, differential waveform may need update

Version 1.2.14

• added support for 6" 1448x1072 ED060KC1 on Waveshare e-Paper IT8951 Driver HAT
• fixed GxEPD2_WiFi_Example.ino: new GitHub fingerprint for ESP8266, certificate for ESP32
• fixed color discriminator for 7-color display in GxEPD2_7C.h
• added multicolor support for 7-color display in GxEPD2_WiFi_Example, GxEPD2_Spiffs_Example,
• and GxEPD2_SD_Example, GxEPD2_SerialFlash_Example
• fixed paged write to 7-color display controller (transaction and CS handling issue)
• some more fixes

Version 1.2.13

• added support for GDEH0154Z90 1.54" 200x200 b/w/r, replacement for GDEW0154Z04
• GDEH0154Z90 has partial window addressing, but no partial window refresh
• added some missing constructor examples, e.g. for IT8951 Driver HAT on Due
• cleaned-up wiring information in the examples

Version 1.2.12

• fixed GxEPD2_MinimumExample.ino to draw black on white (white on white was invisible)
• added example GxEPD2_HelloWorld.ino
• updated wiring info and constructor parameters for the actual Waveshare e-Paper ESP8266 Driver Board
• added some missing explicit initializers (nobody noticed as compilers usually initialize simple members)

Version 1.2.11

• added support for Waveshare 5.65" 7-color e-paper display 600x448
• the unknown controller of this display doesn't support partial update, as far as known
• 7-color graphics support is available with class GxEPD2_7C
• 7-color graphics support requires paging even on ESP32
• 7-color graphics support causes heavy paging on Arduino UNO, gets very slow
• refresh is quite fast for a color e-paper display: 12 seconds

Version 1.2.10

• added support for GDEH075Z90 7.5" b/w/r 880x528
• the controller of GDEH075Z90 supports partial update, but refesh is full screen
• the controller of GDEH075Z90 doesn't support differential update (not possible on 3-color anyway)
• note: the connector of the GDEH075Z90 is mirrored; connects downward on DESPI-C02
• added optional init parameter "reset_duration" in ms, same default 20ms as before
• reset_duration = 2 may help with "clever" reset circuit of newer boards from Waveshare

Version 1.2.9

• added support for GDEW0154T8 1.54" b/w 152x152
• added support for GDEW0154M09 1.54" b/w 200x200
• added support for GDEW0154M10 1.54" b/w 152x152 DES
• added support for GDEW0583T8 5.83" b/w 648x460
• added option to use class GFX of library GFX_Root instead of Adafruit_GFX
• differential update on GDEW0154M10 is experimental, there is no partial update demo yet

Version 1.2.8

• improved transfer speed for the bigger displays (3.71" and up)

Version 1.2.7

• fix paged drawing of initial screen on GDEH029A1
• sometimes true is false, if applied the wrong way round

Version 1.2.6

• slightly improved differential refresh for GDEW1248T3
• minor fixes

Version 1.2.5

• added support for GDEW1248T3 12.84" b/w panel on Waveshare 12.48 e-paper display frame
• tested with Waveshare Epaper ESP32 Driver Board mounted on connection board
• tested with Arduino UNO mounted on connection board, is extremely slow
• doesn't work with Arduino MEGA on connection board with switch set to ICSP and pins bent out of way, reason unknown
• not tested with other processors
• caution: wiring connector is on 5V side of level converters!

Version 1.2.4

• added support for GDEH0154D67 1.54" b/w, replacement for GDEP015OC1
• added GxEPD2_SerialFlash_Loader, WiFi bitmap downloader for SPI-flash
• added GxEPD2_SerialFlash_Example, SPI-flash example, e.g. for Winbond 25Q16BVSIG
• minor fixes and comment cleanups
• fix refresh(false) in upper layer: add powerOff() after full refresh

Version 1.2.3

• fixed partial update for 2.13" 3-color and 2.9" 3-color e-paper
• partial update can be disabled with attribute usePartialUpdateWindow = false
• added GxEPD2_GFX_Example to show uses of GxEPD2_GFX base class
• replaced GxEPD2_MultiDisplayExample code, same code as GxEPD2_GFX_MultiDisplayExample
• added extras/examples/GxEPD2_T_MultiDisplayExample, alternate example using template functions
• major and minor fixes, such as typos that survived too long

Version 1.2.2

• fixed BMP handling, e.g. for BMPs created by ImageMagick
• see also Arduino Forum Topic https://forum.arduino.cc/index.php?topic=642343.0

Version 1.2.1

• added support for GDEW075T7 7.5" b/w 800x480
• GDEW075T7 has differential update (1.6s) using a charge balancing waveform
• added optional SW SPI support, see /extras/sw_spi/README
• added /extras/tests/GxEPD2_RefreshTests/GxEPD2_RefreshTests.ino, for waveform tuning
• minor fixes
• note that 7.5" e-paper displays don't work reliable if fed from 3.3V Arduino pin

Version 1.2.0

• added "fast partial update" (differential update) for GDEW0371W7 3.7" b/w 240x416
• improved differential update waveform for GDEW026T0 2.6" b/w 152x256
• fixed init code & improved differential update for GDEW042T2 4.2" b/w 300x400
• note that all differential refresh waveforms are a compromise (ghosting, big font use)
• parameters for differential waveform for these display can easily be changed for experimenting
• GDEW042T2 would have greyed background without sustain phase
• GDEW042T2 needs multiple full refreshes after extended use of partial updates

Version 1.1.10

• added support for GDEH0213B73 2.13" b/w, replacement for GDE0213B1, GDEH0213B72
• added support for GDEW026T0 2.6" b/w 152x256
• added support for GDEW0371W7 3.7" b/w 240x416
• added support for GDEW075Z08 7.5" b/w/r 800x480
• GDEW075Z08 does allow (slow) partial update, set usePartialUpdate = false to disable for better image
• changed 4.2" b/w waveform table, for better result with actual panels

Version 1.1.9

• note for ESP8266 when using SS for CS: (wiring suggestion)
• connect 4.7k pull-down from GPIO15 to GND if your board or shield has level converters
• fixes for large displays (use uint16_t for buffer index)

Version 1.1.8

• fix for incomplete download in GxEPD2_WiFi_Example
• added missing method displayWindow() to GxEPD2_GFX base class
• fix and clean up of initial refresh for panels with differential update
• initial refresh needs to be full update, not "fast partial update", for these panels,
• as the screen content may differ from the "previous buffer" content.
• add clean of controller buffer(s) on initial write to controller, for partial update.

Version 1.1.7

• enhanced support for full buffered, non-paged use, for processors with enough RAM
• use void display(bool partial_update_mode = false); corresponds to update() in GxEPD
• use added void displayWindow(uint16_t x, uint16_t y, uint16_t w, uint16_t h);
• use added writeImagePart(...), drawImagePart(...), used by displayWindow()
• added example GxEPD2_NotPagedExample.ino
• several fixes, e.g. parameter range check in setPartialWindow()

Version 1.1.6

• added support for GDEH0213B72 2.13" b/w, replacement for GDE0213B1
• changed SPI speed for IT8951 Driver HAT to 24MHz for write, 10MHz for read
• minor fixes, e.g. centering of text bounding box in GxEPD2_Example

Version 1.1.5

• added support for 6" ED060SCT on Waveshare e-Paper IT8951 Driver HAT
• uses 3.3V data lines, but 5V supply (~80mA active, ~20mA stand-by, sleep doesn't work)
• note: 5V supply needs to be exact and strong; 5V over diode from USB (e.g. Wemos D1 mini) doesn't work!
• note that the IT8951 Driver HAT is panel specific, with flash parameterized by supplier
• this is an initial version

Version 1.1.4+

• added GxEPD2_WS_ESP32_Driver example for Waveshare ESP32 Driver Board

Version 1.1.4

• eliminated double refresh for "fast partial update"
• moved wavetables to the driver classes
• added one explicit drawImage(...) and writeImage(...) method (for removed default paramter values for 1.1.3)
• added init method with added parameter initial, for re-init after processor deep sleep wakeup
• added init parameter pulldown_rst_mode, for special RST handling (not needed for waveshare shield)

Version 1.1.3

• fixed wavetables for GDEW029T5 and GDEW0213I5F
• fixed drawImage(...) overloaded methods signature matching ambiguity

Version 1.1.2

• added support for GDEW029T5
• fixed (added) clipping for partial window
• fixed (added) powerOff() after full update (partial update keeps power on)
• added hibernate() for minimum power use by displays that support it

Version 1.1.1

• 2.7" b/w GDEW027W3 with fast partial update support, based on new demo code wavetable
• mapping suggestion added for Arduino MEGA
• NOTE: use voltage divider resistors for 5V Arduinos, series resistor is not reliable enough
• ConnectingHardware.md updated

Version 1.1.0

• added support for GDEW0213I5F for 2.13" b/w 104x212 flexible display
• updated GxEPD2_WiFi_Example and GxEPD2_Spiffs_Loader to use BearSSL on ESP8266, for large bitmap downloads

Version 1.0.9

• add GxEPD2_U8G2_Fonts_Example, e.g. for use of Umlauts ÄÖÜäéöü
• NOTE: you need to SAVE the modified example to a saveable location for UTF-8 characters to work

Version 1.0.8

• add GxEPD2_SD_AVR_boards_added.h to GxEPD2_SD_AVR_Example
• with example definitions for non-AVR boards (low level display class use example)

Version 1.0.7

• add GxEPD2_boards_added.h to GxEPD2_Example
• with example definitions for Arduino DUE and MKR1000

Version 1.0.6

• add buffered drawing option to GxEPD2_WiFi_Example
• allows use with 1.54" 3-color 200x200 display, may also be useful for small bitmaps

Version 1.0.5

• add buffered drawing option to GxEPD2_SD_Example and GxEPD2_Spiffs_Example
• allows use with 1.54" 3-color 200x200 display, may also be useful for small bitmaps

Version 1.0.4

• add GxEPD2_GFX base class support (optional, selectable, uses slightly more code)
• base class GxEPD2_GFX can be used to pass references or pointers to the display instance as parameter
• add GxEPD2_GFX_MultiDisplayExample, uses GxEPD2_GFX reference parameter
• modify GxEPD2_MultiDisplayExample for ESP8266 (template issue: class expected instead of typename)

Version 1.0.3

• fix GxEPD2_SD_Example & GxEPD2_SD_AVR_Example
• add GxEPD2_MultiDisplayExample (preliminary version)

Version 1.0.2

• initial release version 1.0.2
• tested with ESP8266, ESP32, STM32F103C8T6, AVR Arduino (Pro Mini 3.3V)
• 1.54" 3-color GxEPD2_154c can be used with paging for AVR
• wave tables in program space, 4.2" b/w can be used with GxEPD2_SD_AVR_Example
• issues enabled and welcome, please use Forum Topic for enhancement suggestions

Version 1.0.1

• pre-release test version
• GxEPD2_SD_AVR_Example added, has no graphics buffer to reduce RAM usage (base display class use)
• issues disabled so far, use Arduino Forum Topics instead
• in this version 1.54" 3-color GxEPD2_154c can only be used with full size buffer (or with no buffer base display class)

Version 1.0.0

• preliminary version, under construction