u8g Module

U8glib is a graphics library developed at olikraus/u8glib with support for many different displays. The NodeMCU firmware supports a subset of these.

I²C and SPI mode:

  • sh1106_128x64
  • ssd1306 - 128x64 and 64x48 variants
  • ssd1309_128x64
  • ssd1327_96x96_gr
  • uc1611 - dogm240 and dogxl240 variants

SPI only:

  • ld7032_60x32
  • pcd8544_84x48
  • pcf8812_96x65
  • ssd1322_nhd31oled - bw and gr variants
  • ssd1325_nhd27oled - bw and gr variants
  • ssd1351_128x128 - gh and hicolor variants
  • st7565_64128n - variants 64128n, dogm128/132, lm6059/lm6063, c12832/c12864
  • uc1601_c128032
  • uc1608 - 240x128 and 240x64 variants
  • uc1610_dogxl160 - bw and gr variants
  • uc1611 - dogm240 and dogxl240 variants
  • uc1701 - dogs102 and mini12864 variants

This integration is based on v1.18.1.

Overview

I²C Connection

Hook up SDA and SCL to any free GPIOs. Eg. u8g_graphics_test.lua expects SDA=5 (GPIO14) and SCL=6 (GPIO12). They are used to set up nodemcu's I²C driver before accessing the display:

sda = 5
scl = 6
i2c.setup(0, sda, scl, i2c.SLOW)

SPI connection

The HSPI module is used (more information), so certain pins are fixed:

  • HSPI CLK = GPIO14
  • HSPI MOSI = GPIO13
  • HSPI MISO = GPIO12 (not used)

All other pins can be assigned to any available GPIO:

  • CS
  • D/C
  • RES (optional for some displays)

Also refer to the initialization sequence eg in u8g_graphics_test.lua:

spi.setup(1, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, 8, 8)

Library Usage

The Lua bindings for this library closely follow u8glib's object oriented C++ API. Based on the u8g class, you create an object for your display type.

SSD1306 via I²C:

sla = 0x3c
disp = u8g.ssd1306_128x64_i2c(sla)

SSD1306 via SPI:

cs  = 8 -- GPIO15, pull-down 10k to GND
dc  = 4 -- GPIO2
res = 0 -- GPIO16, RES is optional YMMV
disp = u8g.ssd1306_128x64_hw_spi(cs, dc, res)

This object provides all of u8glib's methods to control the display. Again, refer to u8g_graphics_test.lua to get an impression how this is achieved with Lua code. Visit the u8glib homepage for technical details.

Displays

I²C and HW SPI based displays with support in u8glib can be enabled. To get access to the respective constructors, add the desired entries to the I²C or SPI display tables in app/include/u8g_config.h:

#define U8G_DISPLAY_TABLE_I2C                   \
    U8G_DISPLAY_TABLE_ENTRY(ssd1306_128x64_i2c) \

#define U8G_DISPLAY_TABLE_SPI                      \
    U8G_DISPLAY_TABLE_ENTRY(ssd1306_128x64_hw_spi) \
    U8G_DISPLAY_TABLE_ENTRY(pcd8544_84x48_hw_spi)  \
    U8G_DISPLAY_TABLE_ENTRY(pcf8812_96x65_hw_spi)  \

Fonts

u8glib comes with a wide range of fonts for small displays. Since they need to be compiled into the firmware image, you'd need to include them in app/include/u8g_config.h and recompile. Simply add the desired fonts to the font table:

#define U8G_FONT_TABLE \
    U8G_FONT_TABLE_ENTRY(font_6x10)  \
    U8G_FONT_TABLE_ENTRY(font_chikita)

They'll become available as u8g.<font_name> in Lua.

Bitmaps

Bitmaps and XBMs are supplied as strings to drawBitmap() and drawXBM(). This off-loads all data handling from the u8g module to generic methods for binary files. See u8g_bitmaps.lua. In contrast to the source code based inclusion of XBMs into u8glib, it's required to provide precompiled binary files. This can be performed online with Online-Utility's Image Converter: Convert from XBM to MONO format and upload the binary result with nodemcu-uploader.py.

I²C Display Drivers

Initialize a display via I²C.

  • u8g.sh1106_128x64_i2c()
  • u8g.ssd1306_128x64_i2c()
  • u8g.ssd1306_64x48_i2c()
  • u8g.ssd1309_128x64_i2c()
  • u8g.ssd1327_96x96_gr_i2c()
  • u8g.uc1611_dogm240_i2c()
  • u8g.uc1611_dogxl240_i2c()

Syntax

u8g.ssd1306_128x64_i2c(address)

Parameters

address I²C slave address of display

Returns

u8g display object

Example

sda = 5
scl = 6
i2c.setup(0, sda, scl, i2c.SLOW)

sla = 0x3c
disp = u8g.ssd1306_128x64_i2c(sla)

See also

SPI Display Drivers

SPI Display Drivers

Initialize a display via Hardware SPI.

  • u8g.ld7032_60x32_hw_spi()
  • u8g.pcd8544_84x48_hw_spi()
  • u8g.pcf8812_96x65_hw_spi()
  • u8g.sh1106_128x64_hw_spi()
  • u8g.ssd1306_128x64_hw_spi()
  • u8g.ssd1306_64x48_hw_spi()
  • u8g.ssd1309_128x64_hw_spi()
  • u8g.ssd1322_nhd31oled_bw_hw_spi()
  • u8g.ssd1322_nhd31oled_gr_hw_spi()
  • u8g.ssd1325_nhd27oled_bw_hw_spi()
  • u8g.ssd1325_nhd27oled_gr_hw_spi()
  • u8g.ssd1327_96x96_gr_hw_spi()
  • u8g.ssd1351_128x128_332_hw_spi()
  • u8g.ssd1351_128x128gh_332_hw_spi()
  • u8g.ssd1351_128x128_hicolor_hw_spi()
  • u8g.ssd1351_128x128gh_hicolor_hw_spi()
  • u8g.ssd1353_160x128_332_hw_spi()
  • u8g.ssd1353_160x128_hicolor_hw_spi()
  • u8g.st7565_64128n_hw_spi()
  • u8g.st7565_dogm128_hw_spi()
  • u8g.st7565_dogm132_hw_spi()
  • u8g.st7565_lm6059_hw_spi()
  • u8g.st7565_lm6063_hw_spi()
  • u8g.st7565_nhd_c12832_hw_spi()
  • u8g.st7565_nhd_c12864_hw_spi()
  • u8g.uc1601_c128032_hw_spi()
  • u8g.uc1608_240x128_hw_spi()
  • u8g.uc1608_240x64_hw_spi()
  • u8g.uc1610_dogxl160_bw_hw_spi()
  • u8g.uc1610_dogxl160_gr_hw_spi()
  • u8g.uc1611_dogm240_hw_spi()
  • u8g.uc1611_dogxl240_hw_spi()
  • u8g.uc1701_dogs102_hw_spi()
  • u8g.uc1701_mini12864_hw_spi()

Syntax

u8g.ssd1306_128x64_spi(cs, dc[, res])

Parameters

  • cs GPIO pin for /CS
  • dc GPIO pin for DC
  • res GPIO pin for /RES (optional)

Returns

u8g display object

Example

spi.setup(1, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, 8, 8)

cs  = 8 -- GPIO15, pull-down 10k to GND
dc  = 4 -- GPIO2
res = 0 -- GPIO16, RES is optional YMMV
disp = u8g.ssd1306_128x64_hw_spi(cs, dc, res)

See also

I²C Display Drivers


Constants

Constants for various functions.

u8g.DRAW_UPPER_RIGHT, u8g.DRAW_UPPER_LEFT, u8g.DRAW_LOWER_RIGHT, u8g.DRAW_LOWER_LEFT, u8g.DRAW_ALL, u8g.MODE_BW, u8g.MODE_GRAY2BIT

u8g.font_6x10, ...

u8g.disp Sub-Module

u8g.disp:begin()

See u8glib begin().

u8g.disp:drawBitmap()

Draw a bitmap at the specified x/y position (upper left corner of the bitmap). Parts of the bitmap may be outside the display boundaries. The bitmap is specified by the array bitmap. A cleared bit means: Do not draw a pixel. A set bit inside the array means: Write pixel with the current color index. For a monochrome display, the color index 0 will usually clear a pixel and the color index 1 will set a pixel.

Syntax

disp:drawBitmap(x, y, cnt, h, bitmap)

Parameters

  • x X-position (left position of the bitmap)
  • y Y-position (upper position of the bitmap)
  • cnt number of bytes of the bitmap in horizontal direction. The width of the bitmap is cnt*8.
  • h height of the bitmap
  • bitmap bitmap data supplied as string

Returns

nil

See also

u8g.disp:drawBox()

See u8glib drawBox().

u8g.disp:drawCircle()

See u8glib drawCircle().

u8g.disp:drawDisc()

See u8glib drawDisc().

u8g.disp:drawEllipse()

See u8glib drawEllipse().

u8g.disp:drawFilledEllipse()

See u8glib drawFilledEllipse.

u8g.disp:drawFrame()

See u8glib drawFrame().

u8g.disp:drawHLine()

See u8glib drawHLine().

u8g.disp:drawLine()

See u8glib drawLine().

u8g.disp:drawPixel()

See u8glib drawPixel().

u8g.disp:drawRBox()

See u8glib drawRBox().

u8g.disp:drawRFrame()

See u8glib drawRFrame().

u8g.disp:drawStr()

See u8glib drawStr().

u8g.disp:drawStr90()

See u8glib drawStr90.

u8g.disp:drawStr180()

See u8glib drawStr180().

u8g.disp:drawStr270()

See u8glib drawStr270().

u8g.disp:drawTriangle()

See u8glib drawTriangle().

u8g.disp:drawVLine()

See u8glib drawVLine().

u8g.disp:drawXBM()

Draw a XBM Bitmap. Position (x,y) is the upper left corner of the bitmap. XBM contains monochrome, 1-bit bitmaps. This procedure only draws pixel values 1. The current color index is used for drawing (see setColorIndex). Pixel with value 0 are not drawn (transparent).

Bitmaps and XBMs are supplied as strings to drawBitmap() and drawXBM(). This off-loads all data handling from the u8g module to generic methods for binary files. In contrast to the source code based inclusion of XBMs into u8glib, it's required to provide precompiled binary files. This can be performed online with Online-Utility's Image Converter: Convert from XBM to MONO format and upload the binary result with nodemcu-uploader.py or ESPlorer.

Syntax

disp:drawXBM(x, y, w, h, bitmap)

Parameters

  • x X-position (left position of the bitmap)
  • y Y-position (upper position of the bitmap)
  • w width of the bitmap
  • h height of the bitmap
  • bitmap XBM data supplied as string

Returns

nil

See also

u8g.disp:firstPage()

See u8glib firstPage().

u8g.disp:getColorIndex()

See u8glib getColorIndex().

u8g.disp:getFontAscent()

See u8glib getFontAscent().

u8g.disp:getFontDescent()

See u8glib getFontDescent().

u8g.disp:getFontLineSpacing()

See u8glib getFontLineSpacing().

u8g.disp:getHeight()

See u8glib getHeight().

u8g.disp:getMode()

See u8glib getMode().

u8g.disp:getWidth()

See u8glib getWidth().

u8g.disp:getStrWidth()

See u8glib getStrWidth.

u8g.disp:nextPage()

See [u8glib nextPage()(https://github.com/olikraus/u8glib/wiki/userreference#nextpage).

u8g.disp:setColorIndex()

See u8glib setColorIndex().

u8g.disp:setDefaultBackgroundColor()

See u8glib setDefaultBackgroundColor().

u8g.disp:setDefaultForegroundColor()

See u8glib setDefaultForegroundColor().

u8g.disp:setFont()

u8glib comes with a wide range of fonts for small displays. Since they need to be compiled into the firmware image, you'd need to include them in app/include/u8g_config.h and recompile. Simply add the desired fonts to the font table:

#define U8G_FONT_TABLE \
    U8G_FONT_TABLE_ENTRY(font_6x10)  \
    U8G_FONT_TABLE_ENTRY(font_chikita)

They'll be available as u8g.<font_name> in Lua.

Syntax

disp:setFont(font)

Parameters

font Constant to indentify pre-compiled font

Returns

nil

Example

disp:setFont(u8g.font_6x10)

See also

u8g.disp:setFontLineSpacingFactor()

See u8glib setFontLineSpacingFactor().

u8g.disp:setFontPosBaseline()

See u8glib setFontPosBaseline().

u8g.disp:setFontPosBottom()

See u8glib setFontPosBottom().

u8g.disp:setFontPosCenter()

See u8glib setFontPosCenter().

u8g.disp:setFontPosTop()

See u8glib setFontPosTop().

u8g.disp:setFontRefHeightAll()

See u8glib setFontRefHeightAll().

u8g.disp:setFontRefHeightExtendedText()

See u8glib setFontRefHeightExtendedText().

u8g.disp:setFontRefHeightText()

See u8glib setFontRefHeightText().

u8g.disp:setRot90()

See u8glib setRot90().

u8g.disp:setRot180()

See u8glib setRot180().

u8g.disp:setRot270()

See u8glib setRot270().

u8g.disp:setScale2x2()

See u8glib setScale2x2().

u8g.disp:sleepOn()

See u8glib sleepOn().

u8g.disp:sleepOff()

See u8glib sleepOff().

u8g.disp:undoRotation()

See u8glib undoRotation().

u8g.disp:undoScale()

See u8glib undoScale().

Unimplemented Functions

  • Cursor handling
    • disableCursor()
    • enableCursor()
    • setCursorColor()
    • setCursorFont()
    • setCursorPos()
    • setCursorStyle()
  • General functions
    • setContrast()
    • setPrintPos()
    • setHardwareBackup()
    • setRGB()
    • setDefaultMidColor()