Framebuffer API

Implement custom display chips with pixel-level control

Use the framebuffer API to implement displays (LCD, OLED, e-paper, etc.). The display size is defined in the .chip.json file. The framebuffer uses 32 bits per pixel. The pixels are stored in the RGBA format. The total size of the buffer is pixel_width * pixel_height * 4 bytes.

framebuffer_init

buffer_t framebuffer_init(uint32_t *pixel_width, uint32_t *pixel_height)

Returns the framebuffer for the current chip, and the pixel dimensions (width/height) of the frame buffer.

Note: framebuffer_init can only be called from chip_init(). Do not call it at a later time.

buffer_write

void buffer_write(buffer_t buffer, uint32_t offset, void *data, uint32_t data_len)

Copies data_len bytes from data into the frame buffer, at the given offset.

buffer_read

void buffer_read(buffer_t buffer, uint32_t offset, void *data, uint32_t data_len)

Copies data_len bytes at the given offset of the frame buffer into data.

Simulator examples

• Basic Framebuffer Chip Example
• SSD1306 I2C OLED Display
• IL9163 128x128 Color LCD Display Driver