- Name : ER_OLEDM1_CH1115
- Title : Library to support the ER-OLEDM1.09-1 OLED Display Module driven by the CH1115 controller for the Arduino eco-system.
- Description :
- Arduino eco-system library.
- Invert colour, vertical rotate, sleep, fade effect, horizontal scroll and contrast control functions supported.
- 12 ASCII fonts included.
- Graphics support included.
- Multi Screen, single shared buffer mode.
- Bitmaps supported.
- Hardware & software SPI options
-
Author: Gavin Lyons
-
Light weight basic text version here at link..
Output Screenshots, From left to right, top to bottom.
- Full screen bitmap displayed
- Shared Screen mode, screen divided into two Screens with one buffer, Frame rate per second demo.
- Shared Screen mode, screen divided into two Screens with one buffer, clock demo.
- Different size and type of fonts
- Available ASCII font printed out 0-127
- Extended ASCII font printed out 128-255
- Font 1-4
- Font 7
The library is included in the official Arduino library manger and the optimum way to install it is using the library manager which can be opened by the manage libraries option in Arduino IDE.
CH1115 is a single-chip CMOS OLED driver with controller for organic light emitting diode dot-matrix graphic display system. CH1115 consists of 128 segments, 64 commons that can support a maximum display resolution of 128 X 64. It is designed for Common Cathode type OLED panel. ER-OLEDM1.09-1W-SPI is a White 1.09" OLED Display Panel with Breakout Board. This module is a combination of the two.(controller and OLED)
| pin no | pin name | pin desc |
|---|---|---|
| 1 | Gnd | Ground |
| 2 | VCC | voltage supply |
| 3 | SCL | Serial clock input |
| 4 | SDA | Serial data input |
| 5 | RES | This pin is reset signal input. When the pin is low, initialization of the chip is executed. |
| 6 | DC | This pin is Data or Command control pin. |
| 7 | CS | This pin is chip select input. The chip is enabled for MCU comms when CS is pulled low |
VCC The CH1115 controller chip is a 3.3V device but the ERM LCD module has a "662k" 3.3V regulator at back. So the ERM OLED module VCC will also run at 5V.
Logic lines The logic lines where always connected to 3.3 Volts logic during all testing of library. The system can also run at 5 volts logic, the manufacture has instructional videos connected to an Arduino Mega.
This wiring Diagram from the manufacturer datasheet showing hardware setup connected to a 3.3 volt system MCU.
The API (application programming interface) documentation is at link hosted on github pages and generated by Doxygen.
Hardware and software SPI. Two different class constructors. User can pick the relevant constructor, see examples files. Hardware SPI is recommended, far faster and more reliable but Software SPI allows for more flexible GPIO selection. When running Software SPI it may be necessary on very fast high frequency MCU's to change the ERMCH1115_HIGHFREQ_DELAY define, It is a microsecond delay by default it is at 0. All the hardware SPI settings are defined in the header file and can be easily changed if necessary.
The library features a multi-screen shared buffer mode, In order to save data memory.
For example if user defines a buffer to cover the whole screen it takes 1024 bytes of data memory. Instead a user can create a buffer that covers half the screen for just 512 bytes then define two screens each pointing to the same buffer. The user uses the ERMCH1115_SharedBuffer Class objects to define each screen and the ActiveBufferPtr pointer to switch between each screen. Multiple screens of same size can be created so OLED screen can be divided into thirds or quarters saving even more memory. The disadvantage of this is the code is slightly more complicated and user can only write to one screen at a time. If user does not want to use multi screen mode they can simply just define ONE screen to cover entire OLED screen. See example files for more detail.
Font data table:
| num | enum name | Char size XbyY | ASCII range | Size bytes | Size Scale-able |
|---|---|---|---|---|---|
| 1 | $_Default | 5x8 | 0-0x7F | 635 | Y |
| 2 | $_Thick | 7x8 | 0x20-0x5A, no lowercase letters | 406 | Y |
| 3 | $_SevenSeg | 4x8 | 0x20-0x7A | 360 | Y |
| 4 | $_Wide | 8x8 | 0x20-0x5A, no lowercase letters | 464 | Y |
| 5 | $_Tiny | 3x8 | 0x20-0x7E | 285 | Y |
| 6 | $_Homespun | 7x8 | 0x20-0x7E | 658 | Y |
| 7 | $_Bignum | 16x32 | 0x2D-0x3A ,0-10 - . / : | 896 | N |
| 8 | $_Mednum | 16x16 | 0x2D-0x3A ,0-10 - . / : | 448 | N |
| 9 | $_ArialRound | 16x24 | 0x20-0x7E | 4608 | N |
| 10 | $_ArialBold | 16x16 | 0x20-0x7E | 3072 | N |
| 11 | $_Mia | 8x16 | 0x20-0x7E | 1520 | N |
| 12 | $_Dedica | 6x12 | 0x20-0x7E | 1152 | N |
- $ = CH1115Font
- Fonts 1-6 are byte high(at text size 1) scale-able fonts, columns of padding added by SW.
- Font 7-8 are large numerical fonts and cannot be scaled(just one size).
- Fonts 9-12 Alphanumeric fonts and cannot be scaled(just one size)
Font Methods:
| Font num | Method | Size parameter | Notes |
|---|---|---|---|
| 1-6 | drawChar | Y | draws single character |
| 1-6 | drawText | Y | draws character array |
| 7-12 | drawChar | N | draws single character |
| 7-12 | drawText | N | draws character array |
| 1-12 | ~ | Polymorphic print class which will print out many data types(arduino built in) |
These functions return a enum( CH1115_Return_Codes_e), non-zero in event of an error, see API doc. By default only Font 1 is commented in and ready to go to save memory. So to use a non-default Font (2-12), two steps. Comment in the respective define at top of library header file ERM19264_UC1609_graphics_font.h in the USER FONT OPTION ONE section Call SetFontNum method and pass it name of respective font. eg SetFontNum(CH1115Font_Wide).
There is a few different ways of displaying bitmaps,
| Num | Method | Data addressing | Note |
|---|---|---|---|
| 1 | OLEDBitmap() | Vertical | Writes directly to screen , no buffer used. |
| 2 | OLEDBuffer() | Vertical | Mostly for internal use ... mostly |
| 3 | buffer init technique | Vertical | Can be used when initialising a buffer, splash screen |
| 4 | drawBitmap() | Vertical | default, setDrawBitmapAddr(true) |
| 5 | drawBitmap() | Horizontal | setDrawBitmapAddr(false) |
The drawBitmap function will return an enum with an error code if an error occurs see API docs. See the bitmap example file for more details on each method. Bitmaps can be turned to data here at link .
When the user calls OLEDbegin() to start OLED they can specify a contrast setting from 0x00 to 0xFF. Datasheet says 0x80 is default. User can also change contrast on the fly. Screen can be disabled to enter a sleep type mode where OLED draws 500uA. Screen pixel colour can be inverted and also screen can be vertically rotated.
There is a "fade or breath display effect". Whose parameters(time brightness) can be adjusted by passing data to function see "OLEDfadeEffect" in API and datasheet for more details. default is 0x81.
There is a Horizontal scroll effect. Whose parameters: Time-interval , direction , mode, can be adjusted by passing data to function see "OLEDscrollSetup" in API and datasheet for details. defaults are : 6 frames , right , continuous mode.
X = ER_OLEDM1_CH1115 in tables below
| Src Files | Description |
|---|---|
| X.hpp | library header file |
| X.cpp | library source file |
| X_graphics.hpp | graphics header file |
| X_graphics.cpp | graphics source file |
| X_graphics_font.hpp | font file |
| X_graphics_font.cpp | font data file |
The example files are setup for an arduino UNO/NANO
| Examples files ino | Description |
|---|---|
| X_BITMAPS | Shows use of bitmaps |
| X_GRAPHICS | Tests use of graphics |
| X_FUNCTIONS | Shows misc functions: flip, scroll , rotate, invert etc |
| X_MBUF | Shows use of shared buffer mode |
| X_CLOCK | Shows use of shared buffer mode + clock demo |
| X_TEXT | Shows use of text and fonts, All Fonts must be enabled to work fully |
| X_SWSPI | Shows use of software SPI |
| X_HELLO | Hello world, basic use case |
Tested on following MCUs. for the pin connections used during testing see extras folder, GPIO_MCU_used.txt file.
- Arduino UNO & NANO v3
- ESP8266
- ESP32
- STM32 "blue pill"
- Arduino Uno R4 Minima