C Library for SSD1306 0.96" OLED display
SSD1306 Description
Detailed information are described in Datasheet SSD1306.
Library
C library is aimed for driving 0.96" OLED display with SSD1306 driver 128x64 or 128x32 version through TWI's (I2C). Settings for particular versions:
- 128x64 version
- command argument SSD1306_SET_MUX_RATIO set to 0x3F (ssd1306.c)
- command argument SSD1306_COM_PIN_CONF set to 0x12 (ssd1306.c)
- END_PAGE_ADDR set to 7 (ssd1306.h)
- 128x32 version
- command argument SSD1306_SET_MUX_RATIO set to 0x1F (ssd1306.c)
- command argument SSD1306_COM_PIN_CONF set to 0x02 (ssd1306.c)
- END_PAGE_ADDR set to 3 (ssd1306.h)
Versions
- 1.0 - basic functions. The first publication.
- 2.0 - more changes:
- rebuild to 'cacheMemLcd' array approach. It means that every request is stored in 'cacheMemLcd' array (RAM) and by the SSD1306_UpdateScreen (uint8_t) function is printed on the display.
- added new function -> SSD1306_DrawLine (uint8_t, uint8_t, uint8_t, uint8_t). Possible depicted any line (horizontal, vertical, with slope).
- possible to use for more than 1 display (not tested).
- !!! ~1kB RAM memory consumption.
- 3.0 - simplified alphanumeric version
- displaying alphanumeric characters
- for one display applicable
- only few RAM bytes consumption
- !!! no graphic functions like drawLine
- 3.1 - simplified version with draw lines
- displaying alphanumeric characters with graphic functions like drawLine vertical & horizontal
- for one display applicable
- only few RAM bytes consumption
- horizontal scroll function added
Dependencies
Font.c can be modified according to application requirements with form defined in font.c. Maximal permissible horizontal dimension is 8 bits.
Usage
Prior defined for MCU Atmega328p / Atmega8 / Atmega16. Need to be carefull with TWI ports definition.
| PORT | Atmega16 | Atmega8 / Atmega328 |
|---|---|---|
| SCL | PC0 | PC5 |
| SDA | PC1 | PC4 |
Picture of hardware connection
Tested
Library was tested and proved with 0.96″ 128x64 and 0.91" 128x32 OLED Display (SSD1306 driver) and Arduino UNO R3. The Arduino was without a bootloader installed, it was only raw Atmega328P microcontroller. Communication was done through I2C (TWI) interface of Arduino UNO R3. This hardware configuration was chosen for simplicity.
Init OLED Sequence
Init sequence OLED display was defined mainly according to page 64 (next to last page) of Datasheet SSD1306.
Flowchart
// +---------------------------+
// | Software Reset | // not tested yet, @source https://github.com/SmingHub/Sming/issues/501
// +---------------------------+
// | 0xE4 |
// +---------------------------+
// ||
// +---------------------------+
// | DISPLAY OFF |
// +---------------------------+
// | 0xAE |
// +---------------------------+
// ||
// +---------------------------+
// | Set MUX Ratio |
// +---------------------------+
// | 0xA8 |
// | 0x3F |
// +---------------------------+
// ||
// +---------------------------+
// | Set Memory Addr Mode |
// +---------------------------+
// | 0x20 |
// | 0x00 |
// +---------------------------+
// ||
// +---------------------------+
// | Set Start Line |
// +---------------------------+
// | 0x40 |
// +---------------------------+
// ||
// +---------------------------+
// | Set Display Offset |
// +---------------------------+
// | 0xD3 |
// | 0x00 |
// +---------------------------+
// ||
// +---------------------------+
// | Set Segment Remap |
// +---------------------------+
// | 0xA0 or 0xA1 |
// +---------------------------+
// ||
// +---------------------------+
// | Set COM Output Scan |
// | Direction |
// +---------------------------+
// | 0xC0 or 0xC8 |
// +---------------------------+
// ||
// +---------------------------+
// | Set COM Pins hardware |
// | configuration |
// +---------------------------+
// | 0xDA |
// | 0x12 for 128x64 |
// | 0x02 for 128x32 |
// +---------------------------+
// ||
// +---------------------------+
// | Set Contrast Control |
// +---------------------------+
// | 0x81 |
// | 0x7F |
// +---------------------------+
// ||
// +---------------------------+
// | Disable Entire Display On |
// +---------------------------+
// | 0xA4 |
// +---------------------------+
// ||
// +---------------------------+
// | Set Normal Display |
// +---------------------------+
// | 0xA6 |
// +---------------------------+
// ||
// +---------------------------+
// | Set OSC Frequency Fosc |
// +---------------------------+
// | 0xD5 |
// | 0x80 |
// +---------------------------+
// ||
// +---------------------------+
// | Enable charge pump |
// | regulator |
// +---------------------------+
// | 0x8D |
// | 0x14 |
// +---------------------------+
// ||
// +---------------------------+
// | Deactivate Scroll |
// +---------------------------+
// | 0x2E |
// +---------------------------+
// ||
// +---------------------------+
// | Display On |
// +---------------------------+
// | 0xAF |
// +---------------------------+Functions
- SSD1306_Init (uint8_t) - Init display
- SSD1306_ClearScreen (void) - Clear screen
- SSD1306_NormalScreen (uint8_t) - Normal screen
- SSD1306_InverseScreen (uint8_t) - Inverse screen
- SSD1306_SetPosition (uint8_t, uint8_t) - Set position
- SSD1306_DrawChar (char) - Draw specific character
- SSD1306_DrawString (char*) - Draw specific string
- SSD1306_UpdateScreen (uint8_t) - Update content on display
- SSD1306_DrawLine (uint8_t, uint8_t, uint8_t, uint8_t) - Draw line
Demonstration version v1.0.0
Demonstration version v2.0.0
Demonstration version v3.0.0
