SSD1306Ascii Library

SSD1306Ascii is an unbuffered, character-only library designed for small OLED displays using SSD1306 controllers (such as the Adafruit 1.3" and 0.96" Monochrome displays).

Key characteristics:

• Unbuffered: It does not use a full frame buffer, making it extremely memory-efficient.
• Low RAM usage: It requires only a few bytes of RAM. For example, a 'Hello world!' SPI sketch on an Arduino Uno uses only 54 bytes (2%) of dynamic memory.
• Compatibility: Runs on Arduino AVR boards, Arduino Due, and other Arduino-style boards that support the SPI or Wire libraries.

The set400kHz() method is a deprecated helper to set the I2C clock rate to 400 kHz. It is recommended to use the standard Arduino Wire.setClock(400000L) method instead.

// Deprecated: use Wire.setClock(400000L) instead
oled.set400kHz();

The begin() method initializes the pins and the display controller. It has two overloads:

1. void begin(const DevType* dev, uint8_t cs, uint8_t dc, uint8_t clk, uint8_t data)

   • dev: A pointer to a DevType initialization structure.
   • cs: Chip select pin.
   • dc: Data/command pin.
   • clk: SPI clock pin.
   • data: SPI MOSI pin.

2. void begin(const DevType* dev, uint8_t cs, uint8_t dc, uint8_t clk, uint8_t data, uint8_t rst)

   • dev: A pointer to a DevType initialization structure.
   • cs: Chip select pin.
   • dc: Data/command pin.
   • clk: SPI clock pin.
   • data: SPI MOSI pin.
   • rst: Reset pin. This overload performs a hardware reset (pulling the pin LOW for 10ms, then HIGH for 10ms) before calling the standard initialization.

Use setI2cClock(frequency) to adjust the I2C bit rate in Hz.

Note for 16 MHz boards: The valid frequency range is approximately 40 kHz to 444,000 Hz.

display.setI2cClock(400000); // Set to 400 kHz

If your project uses MULTIPLE_I2C_PORTS, you can instantiate SSD1306AsciiWire on a specific I2C bus by passing the desired Wire instance to the constructor. If MULTIPLE_I2C_PORTS is not defined, the class defaults to using the standard Wire object.

// Using a specific I2C bus (e.g., Wire1)
SSD1306AsciiWire oled(Wire1);

The SSD1306AsciiWire class is used to interface with SSD1306 OLED displays via the I2C protocol using the Arduino Wire library.

To initialize the display, use the begin() method. You must provide a DevType structure (defined in the base SSD1306Ascii class) and the I2C address of the display.

If your hardware includes a reset pin, you can use the overloaded begin() method that accepts a reset pin number to perform a hardware reset before initialization.

// Basic initialization
SSD1306AsciiWire oled;
// dev is a pointer to a DevType configuration structure
oled.begin(&dev, 0x3C);

// Initialization with a hardware reset pin
// rst is the GPIO pin number connected to the OLED reset pin
oled.begin(&dev, 0x3C, RST_PIN);

Use the SSD1306AsciiSoftSpi class to drive SSD1306 displays using bit-banged (software) SPI. This is useful when you need to use pins other than the hardware SPI pins. You can initialize the display using two versions of the begin() method: one that only requires the SPI pins, and one that also includes a reset pin.

// Using begin() without a reset pin
// dev: pointer to device initialization structure
// cs: chip select pin
// dc: data/command pin
// clk: clock pin
// data: MOSI pin
display.begin(dev, cs_pin, dc_pin, clk_pin, data_pin);

// Using begin() with a reset pin
// rst: reset pin
display.begin(dev, cs_pin, dc_pin, clk_pin, data_pin, rst_pin);

Use the begin() method to initialize an SSD1306 I2C display on an AVR-based board. This class uses the AvrI2c library, which is optimized to be smaller and faster than the standard Arduino Wire library.

You can initialize the display in two ways:

1. Standard initialization: Provide a device initialization structure (DevType) and the I2C address.
2. With Reset Pin: Provide the device initialization structure, the I2C address, and the specific GPIO pin used for the display's reset (rst).

// Standard initialization
display.begin(&dev, 0x3C);

// Initialization with a reset pin
display.begin(&dev, 0x3C, RST_PIN);