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.
• 2.0.0 - 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.

Dependencies

• font.h
• twi.c
• twi.h

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

Tested

Library was tested and proved on 0.96″ OLED Display with SSD1306 driver and Atmega328p.

Init OLED Sequence

Init sequence OLED display was defined according to page 64 (next to last page) of Datasheet SSD1306.

// +---------------------------+
// |      Set MUX Ratio        |
// +---------------------------+
// |        0xA8, 0x3F         |
// +---------------------------+
//              |
// +---------------------------+
// |    Set Display Offset     |
// +---------------------------+
// |        0xD3, 0x00         |
// +---------------------------+
//              |
// +---------------------------+
// |  Set Display Start Line   |
// +---------------------------+
// |          0x40             |
// +---------------------------+
//              |
// +---------------------------+
// |     Set Segment Remap     |
// +---------------------------+
// |       0xA0 / 0xA1         |
// +---------------------------+
//              |
// +---------------------------+
// |   Set COM Output Scan     |
// |        Direction          |
// +---------------------------+
// |       0xC0 / 0xC8         |
// +---------------------------+
//              |
// +---------------------------+
// |   Set COM Pins hardware   |
// |       configuration       |
// +---------------------------+
// |        0xDA, 0x02         |
// +---------------------------+
//              |
// +---------------------------+
// |   Set Contrast Control    |
// +---------------------------+
// |        0x81, 0x7F         |
// +---------------------------+
//              |
// +---------------------------+
// | Disable Entire Display On |
// +---------------------------+
// |          0xA4             |
// +---------------------------+
//              |
// +---------------------------+
// |    Set Normal Display     |
// +---------------------------+
// |          0xA6             |
// +---------------------------+
//              |
// +---------------------------+
// |    Set Osc Frequency      |
// +---------------------------+
// |       0xD5, 0x80          |
// +---------------------------+
//              |
// +---------------------------+
// |    Enable charge pump     |
// |        regulator          |
// +---------------------------+
// |       0x8D, 0x14          |
// +---------------------------+
//              |
// +---------------------------+
// |        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

Acknowledgement

• Adafruit SSD1306 Library

Links

• Datasheet SSD1306
• Atmega328