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nodemcu-firmware/docs/en/modules/u8g2.md

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u8g2 Module

Since Origin / Contributor Maintainer Source
2017-06-02 Oli Kraus, Arnim Läuger Arnim Läuger u8g2.c

U8g2 is a graphics library developed at olikraus/u8g2 with support for many different displays. It is the successor of U8glib which is not developed any further.

The NodeMCU firmware supports the following displays in I²C and SPI mode:

  • ld7032 60x32
  • sh1106 128x64
  • ssd1305 128x32
  • ssd1306 - 128x32, 128x64, 64x48, and 96x16 variants
  • ssd1309 128x64
  • ssd1325 128x63
  • ssd1327 96x96
  • st7588 jlx12864
  • uc1601 128x32
  • uc1604 jlx19264
  • uc1608 - 240x180 and erc24064 variants
  • ux1610 dogxl160
  • uc1611 - variants dogm240, dogxl240, and ew50850

SPI only:

  • il3820 v2 296x128
  • ist3020 erc19264
  • ls013b7dh03 128x128
  • max7219 32x8
  • nt7534 tg12864r
  • pcd8544 84x48
  • pcf8812 96x65
  • sed1520 122x32
  • ssd1322 nhd 256x64
  • ssd1329 128x96
  • ssd1606 172x72
  • ssd1607 200x200
  • st7565 - variants 64128n, dogm128/132, erc12864, lm6059, c12832/c12864, and zolen 128x64
  • st7567 132x64 and jlx12864 variants
  • st75256 jlx172104 and jlx256128 variants
  • uc1701 - dogs102 and mini12864 variants

This integration is based on v2.19.8.

Overview

I²C Connection

Hook up SDA and SCL to any free GPIOs. Eg. graphics_test.lua expects SDA=GPIO16 and SCL=GPIO17. They are used to set up nodemcu's I²C driver before accessing the display:

id  = i2c.HW0
sda = 16
scl = 17
i2c.setup(id, sda, scl, i2c.FAST)

SPI connection

Hook up pins to any free GPIOs:

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

Again, refer to the initialization sequence eg. in graphics_test.lua:

sclk = 19
mosi = 23
bus = spi.master(spi.HSPI, {sclk=sclk, mosi=mosi})

Library Usage

The Lua bindings for this library closely follow u8g2's object oriented C++ API. Based on the u8g2 class, you create an object for your display type.

SSD1306 via I²C:

sla = 0x3c
disp = u8g2.ssd1306_i2c_128x64_noname(id, sla)

SSD1306 via SPI:

cs  = 22
dc  = 16
res = 0 -- RES is optional YMMV
disp = u8g2.ssd1306_128x64_noname(bus, cs, dc, res)

This object provides all of u8g2's methods to control the display. Refer to graphics_test.lua to get an impression how this is achieved with Lua code. Visit the u8g2 homepage for technical details.

Displays

I²C and HW SPI based displays with support in u8g2 can be enabled. To get access to the respective constructors, enable the desired entries for I²C and SPI displays in u8g2's sub-menu (run make menuconfig).

Fonts

u8g2 comes with a wide range of fonts for small displays. They can be supplied as strings or compiled into the firmware image to decrease the RAM footprint. Simply add the desired fonts to the font selection sub-entry via make menuconfig.

They'll become available as u8g2.<font_name> in Lua.

Bitmaps

XBM bitmaps are supplied as strings to drawXBM(). This off-loads all data handling from the u8g2 module to generic methods for binary files. See graphics_test.lua.

In contrast to the source code based inclusion of XBMs in upstream u8g2 library, 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.

I²C Display Drivers

Initialize a display via I²C.

  • u8g2.ld7032_i2c_60x32()
  • u8g2.sh1106_i2c_128x64_noname()
  • u8g2.sh1106_i2c_128x64_vcomh0()
  • u8g2.ssd1305_i2c_128x32_noname()
  • u8g2.ssd1306_i2c_128x32_univision()
  • u8g2.ssd1306_i2c_128x64_noname()
  • u8g2.ssd1306_i2c_128x64_vcomh0()
  • u8g2.ssd1309_i2c_128x64_noname0()
  • u8g2.ssd1309_i2c_128x64_noname2()
  • u8g2.ssd1306_i2c_64x48_er()
  • u8g2.ssd1306_i2c_96x16_er()
  • u8g2.ssd1325_i2c_nhd_128x64()
  • u8g2.ssd1327_i2c_seeed_96x96()
  • u8g2.st7588_i2c_jlx12864()
  • u8g2.uc1604_i2c_jlx19264()
  • u8g2.uc1608_i2c_erc24064()
  • u8g2.uc1608_i2c_240x128()
  • u8g2.uc1610_i2c_ea_dogxl160()
  • u8g2.uc1611_i2c_ea_dogm240()
  • u8g2.uc1611_i2c_ea_dogxl240()

Syntax

u8g2.ssd1306_i2c_128x64_noname(id, address[, cb_fn])

Parameters

Returns

u8g2 display object

Example

id  = i2c.HW0
sda = 16
scl = 17
sla = 0x3c
i2c.setup(id, sda, scl, i2c.FAST)
disp = u8g2.ssd1306_i2c_128x64_noname(id, sla)

SPI Display Drivers

Initialize a display via Hardware SPI.

  • u8g2.ist3020_erc19264()
  • u8g2.ld7032_60x32()
  • u8g2.ls013b7dh03_128x128()
  • u8g2.max7219_32x8()
  • u8g2.nt7534_tg12864r()
  • u8g2.pcd8544_84x48()
  • u8g2.pcf8812_96x65()
  • u8g2.sh1106_128x64_noname()
  • u8g2.sh1106_128x64_vcomh0()
  • u8g2.ssd1305_128x32_noname()
  • u8g2.ssd1306_128x32_univision()
  • u8g2.ssd1306_128x64_noname()
  • u8g2.ssd1306_128x64_vcomh0()
  • u8g2.ssd1306_64x48_er()
  • u8g2.ssd1306_96x16_er()
  • u8g2.ssd1309_128x64_noname0()
  • u8g2.ssd1309_128x64_noname2()
  • u8g2.sed1520_122x32()
  • u8g2.ssd1322_nhd_256x64()
  • u8g2.ssd1325_nhd_128x64()
  • u8g2.ssd1327_seeed_96x96()
  • u8g2.ssd1329_128x96_noname()
  • u8g2.ssd1606_172x72()
  • u8g2.ssd1607_200x200()
  • u8g2.st7565_64128n()
  • u8g2.st7565_ea_dogm128()
  • u8g2.st7565_ea_dogm132()
  • u8g2.st7565_erc12864()
  • u8g2.st7565_lm6059()
  • u8g2.st7565_nhd_c12832()
  • u8g2.st7565_nhd_c12864()
  • u8g2.st7565_zolen_128x64()
  • u8g2.st7567_pi_132x64()
  • u8g2.st7588_jlx12864()
  • u8g2.st7920_s_128x64()
  • u8g2.st7920_s_192x32()
  • u8g2.uc1604_jlx19264()
  • u8g2.uc1608_240x128()
  • u8g2.uc1608_erc24064()
  • u8g2.uc1610_ea_dogxl160()
  • u8g2.uc1611_ea_dogm240()
  • u8g2.uc1611_ea_dogxl240()
  • u8g2.uc1701_ea_dogs102()
  • u8g2.uc1701_mini12864()

Syntax

u8g2.ssd1306_128x64_noname(cs, dc[, [res][, cb_fn]])

Parameters

  • cs GPIO pin for CS
  • dc GPIO pin for DC
  • res GPIO pin for RES, none if omitted
  • cb_fn optional callback function, see Framebuffer callback

Returns

u8g2 display object

Example

sclk = 19
mosi = 23
cs   = 22
dc   = 16
res  = 17
bus = spi.master(spi.HSPI, {sclk=sclk, mosi=mosi})
disp = u8g2.ssd1306_128x64_noname(bus, cs, dc, res)

Framebuffer callback

Each display type can be initialized to provide the framebuffer contents in run-length encoded format to a Lua callback. This mode is enabled when a callback function is specified for the setup function. Hardware display and framebuffer callback can be operated in parallel. If the callback function is the only parameter then no signals for a hardware display are generated, leaving a virtual display.

The callback function can be used to process the framebuffer line by line. It's called with either nil as parameter to indicate the start of a new frame or with a string containing a line of the framebuffer with run-length encoding. First byte in the string specifies how many pairs of (x, len) follow, while each pair defines the start (leftmost x-coordinate) and length of a sequence of lit pixels. All other pixels in the line are dark.

n = struct.unpack("B", rle_line)
print(n.." pairs")
for i = 0,n-1 do
  print(string.format("  x: %d len: %d", struct.unpack("BB", rle_line, 1+1 + i*2)))
end

Syntax

u8g2.ssd1306_i2c_128x64_noname(id, address[, cb_fn])
u8g2.ssd1306_i2c_128x64_noname(cb_fn)
u8g2.ssd1306_128x64_noname(cs, dc[, [res][, cb_fn]])
u8g2.ssd1306_128x64_noname(cb_fn)

Parameters

  • id, address, cs, dc, res see above
  • cb_fn([rle_line]) callback function. rle_line is a string containing a run-length encoded framebuffer line, or nil to indicate start of frame.

Constants

Constants for various functions.

u8g2.DRAW_UPPER_RIGHT, u8g2.DRAW_UPPER_LEFT, u8g2.DRAW_LOWER_RIGHT, u8g2.DRAW_LOWER_LEFT, u8g2.DRAW_ALL,

u8g2.R0, u8g2.R1, u8g2.R2, u8g2.R3, u8g2.MIRROR,

u8g2.font_6x10, ...