OLED Driver

OLED Supported Hardware

OLED modules using SSD1306 or SH1106 driver ICs, communicating over I2C. Tested combinations:

IC driver

Size

Keyboard Platform

Notes

SSD1306

128x32

AVR

Primary support

SSD1306

128x64

AVR

Verified working

SSD1306

128x32

ARM

SH1106

128x64

AVR

No rotation or scrolling

Hardware configurations using ARM-based microcontrollers or different sizes of OLED modules may be compatible, but are untested.

!> Warning: This OLED Driver currently uses the new i2c_master driver from split common code. If your split keyboard uses I2C to communicate between sides, this driver could cause an address conflict (serial is fine). Please contact your keyboard vendor and ask them to migrate to the latest split common code to fix this. In addition, the display timeout system to reduce OLED burn-in also uses split common to detect keypresses, so you will need to implement custom timeout logic for non-split common keyboards.

Usage

To enable the OLED feature, there are three steps. First, when compiling your keyboard, you'll need to set OLED_DRIVER_ENABLE=yes in rules.mk, e.g.:

OLED_DRIVER_ENABLE = yes

This enables the feature and the OLED_DRIVER_ENABLE define. Then in your keymap.c file, you will need to implement the user task call, e.g:

#ifdef OLED_DRIVER_ENABLE
void oled_task_user(void) {
// Host Keyboard Layer Status
oled_write_P(PSTR("Layer: "), false);
switch (get_highest_layer(layer_state)) {
case _QWERTY:
oled_write_P(PSTR("Default\n"), false);
break;
case _FN:
oled_write_P(PSTR("FN\n"), false);
break;
case _ADJ:
oled_write_P(PSTR("ADJ\n"), false);
break;
default:
// Or use the write_ln shortcut over adding '\n' to the end of your string
oled_write_ln_P(PSTR("Undefined"), false);
}
// Host Keyboard LED Status
uint8_t led_usb_state = host_keyboard_leds();
oled_write_P(led_usb_state & (1<<USB_LED_NUM_LOCK) ? PSTR("NUMLCK ") : PSTR(" "), false);
oled_write_P(led_usb_state & (1<<USB_LED_CAPS_LOCK) ? PSTR("CAPLCK ") : PSTR(" "), false);
oled_write_P(led_usb_state & (1<<USB_LED_SCROLL_LOCK) ? PSTR("SCRLCK ") : PSTR(" "), false);
}
#endif

Logo Example

In the default font, ranges in the font file are reserved for a QMK Logo. To Render this logo to the oled screen, use the following code example:

static void render_logo(void) {
static const char PROGMEM qmk_logo[] = {
0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x88,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x8f,0x90,0x91,0x92,0x93,0x94,
0xa0,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xab,0xac,0xad,0xae,0xaf,0xb0,0xb1,0xb2,0xb3,0xb4,
0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,0xcf,0xd0,0xd1,0xd2,0xd3,0xd4,0};
oled_write_P(qmk_logo, false);
}

Other Examples

In split keyboards, it is very common to have two OLED displays that each render different content and oriented flipped differently. You can do this by switching which content to render by using the return from is_keyboard_master() or is_keyboard_left() found in split_util.h, e.g:

#ifdef OLED_DRIVER_ENABLE
oled_rotation_t oled_init_user(oled_rotation_t rotation) {
if (!is_keyboard_master())
return OLED_ROTATION_180; // flips the display 180 degrees if offhand
return rotation;
}
void oled_task_user(void) {
if (is_keyboard_master()) {
render_status(); // Renders the current keyboard state (layer, lock, caps, scroll, etc)
} else {
render_logo(); // Renders a statuc logo
oled_scroll_left(); // Turns on scrolling
}
}
#endif

Basic Configuration

Define

Default

Description

OLED_DISPLAY_ADDRESS

0x3C

The i2c address of the OLED Display

OLED_FONT_H

"glcdfont.c"

The font code file to use for custom fonts

OLED_FONT_START

0

The starting characer index for custom fonts

OLED_FONT_END

224

The ending characer index for custom fonts

OLED_FONT_WIDTH

6

The font width

OLED_FONT_HEIGHT

8

The font height (untested)

OLED_TIMEOUT

60000

Turns off the OLED screen after 60000ms of keyboard inactivity. Helps reduce OLED Burn-in. Set to 0 to disable.

OLED_SCROLL_TIMEOUT

0

Scrolls the OLED screen after 0ms of OLED inactivity. Helps reduce OLED Burn-in. Set to 0 to disable.

OLED_SCROLL_TIMEOUT_RIGHT

Not defined

Scroll timeout direction is right when defined, left when undefined.

OLED_IC

OLED_IC_SSD1306

Set to OLED_IC_SH1106 if you're using the SH1106 OLED controller.

OLED_COLUMN_OFFSET

0

(SH1106 only.) Shift output to the right this many pixels. Useful for 128x64 displays centered on a 132x64 SH1106 IC.

128x64 & Custom sized OLED Displays

The default display size for this feature is 128x32 and all necessary defines are precalculated with that in mind. We have added a define, OLED_DISPLAY_128X64, to switch all the values to be used in a 128x64 display, as well as added a custom define, OLED_DISPLAY_CUSTOM, that allows you to provide the necessary values to the driver.

Define

Default

Description

OLED_DISPLAY_128X64

Not defined

Changes the display defines for use with 128x64 displays.

OLED_DISPLAY_CUSTOM

Not defined

Changes the display defines for use with custom displays. Requires user to implement the below defines.

OLED_DISPLAY_WIDTH

128

The width of the OLED display.

OLED_DISPLAY_HEIGHT

32

The height of the OLED display.

OLED_MATRIX_SIZE

512

The local buffer size to allocate. (OLED_DISPLAY_HEIGHT / 8 * OLED_DISPLAY_WIDTH).

OLED_BLOCK_TYPE

uint16_t

The unsigned integer type to use for dirty rendering.

OLED_BLOCK_COUNT

16

The number of blocks the display is divided into for dirty rendering. (sizeof(OLED_BLOCK_TYPE) * 8).

OLED_BLOCK_SIZE

32

The size of each block for dirty rendering (OLED_MATRIX_SIZE / OLED_BLOCK_COUNT).

OLED_COM_PINS

COM_PINS_SEQ

How the SSD1306 chip maps it's memory to display. Options are COM_PINS_SEQ, COM_PINS_ALT, COM_PINS_SEQ_LR, & COM_PINS_ALT_LR.

OLED_SOURCE_MAP

{ 0, ... N }

Precalculated source array to use for mapping source buffer to target OLED memory in 90 degree rendering.

OLED_TARGET_MAP

{ 24, ... N }

Precalculated target array to use for mapping source buffer to target OLED memory in 90 degree rendering.

90 Degree Rotation - Technical Mumbo Jumbo

!> Rotation is unsupported on the SH1106.

// OLED Rotation enum values are flags
typedef enum {
OLED_ROTATION_0 = 0,
OLED_ROTATION_90 = 1,
OLED_ROTATION_180 = 2,
OLED_ROTATION_270 = 3, // OLED_ROTATION_90 | OLED_ROTATION_180
} oled_rotation_t;

OLED displays driven by SSD1306 drivers only natively support in hard ware 0 degree and 180 degree rendering. This feature is done in software and not free. Using this feature will increase the time to calculate what data to send over i2c to the OLED. If you are strapped for cycles, this can cause keycodes to not register. In testing however, the rendering time on an atmega32u4 board only went from 2ms to 5ms and keycodes not registering was only noticed once we hit 15ms.

90 Degree Rotated Rendering is achieved by using bitwise operations to rotate each 8 block of memory and uses two precalculated arrays to remap buffer memory to OLED memory. The memory map defines are precalculated for remap performance and are calculated based on the OLED Height, Width, and Block Size. For example, in the 128x32 implementation with a uint8_t block type, we have a 64 byte block size. This gives us eight 8 byte blocks that need to be rotated and rendered. The OLED renders horizontally two 8 byte blocks before moving down a page, e.g:

0

1

2

3

4

5

6

7

However the local buffer is stored as if it was Height x Width display instead of Width x Height, e.g:

3

7

2

6

1

5

0

4

So those precalculated arrays just index the memory offsets in the order in which each one iterates its data.

OLED API

// OLED Rotation enum values are flags
typedef enum {
OLED_ROTATION_0 = 0,
OLED_ROTATION_90 = 1,
OLED_ROTATION_180 = 2,
OLED_ROTATION_270 = 3, // OLED_ROTATION_90 | OLED_ROTATION_180
} oled_rotation_t;
// Initialize the OLED display, rotating the rendered output based on the define passed in.
// Returns true if the OLED was initialized successfully
bool oled_init(oled_rotation_t rotation);
// Called at the start of oled_init, weak function overridable by the user
// rotation - the value passed into oled_init
// Return new oled_rotation_t if you want to override default rotation
oled_rotation_t oled_init_user(oled_rotation_t rotation);
// Clears the display buffer, resets cursor position to 0, and sets the buffer to dirty for rendering
void oled_clear(void);
// Renders the dirty chunks of the buffer to OLED display
void oled_render(void);
// Moves cursor to character position indicated by column and line, wraps if out of bounds
// Max column denoted by 'oled_max_chars()' and max lines by 'oled_max_lines()' functions
void oled_set_cursor(uint8_t col, uint8_t line);
// Advances the cursor to the next page, writing ' ' if true
// Wraps to the begining when out of bounds
void oled_advance_page(bool clearPageRemainder);
// Moves the cursor forward 1 character length
// Advance page if there is not enough room for the next character
// Wraps to the begining when out of bounds
void oled_advance_char(void);
// Writes a single character to the buffer at current cursor position
// Advances the cursor while writing, inverts the pixels if true
// Main handler that writes character data to the display buffer
void oled_write_char(const char data, bool invert);
// Writes a string to the buffer at current cursor position
// Advances the cursor while writing, inverts the pixels if true
void oled_write(const char *data, bool invert);
// Writes a string to the buffer at current cursor position
// Advances the cursor while writing, inverts the pixels if true
// Advances the cursor to the next page, wiring ' ' to the remainder of the current page
void oled_write_ln(const char *data, bool invert);
// Writes a PROGMEM string to the buffer at current cursor position
// Advances the cursor while writing, inverts the pixels if true
// Remapped to call 'void oled_write(const char *data, bool invert);' on ARM
void oled_write_P(const char *data, bool invert);
// Writes a PROGMEM string to the buffer at current cursor position
// Advances the cursor while writing, inverts the pixels if true
// Advances the cursor to the next page, wiring ' ' to the remainder of the current page
// Remapped to call 'void oled_write_ln(const char *data, bool invert);' on ARM
void oled_write_ln_P(const char *data, bool invert);
// Writes a string to the buffer at current cursor position
void oled_write_raw(const char *data, uint16_t size);
// Writes a PROGMEM string to the buffer at current cursor position
void oled_write_raw_P(const char *data, uint16_t size);
// Can be used to manually turn on the screen if it is off
// Returns true if the screen was on or turns on
bool oled_on(void);
// Can be used to manually turn off the screen if it is on
// Returns true if the screen was off or turns off
bool oled_off(void);
// Basically it's oled_render, but with timeout management and oled_task_user calling!
void oled_task(void);
// Called at the start of oled_task, weak function overridable by the user
void oled_task_user(void);
// Scrolls the entire display right
// Returns true if the screen was scrolling or starts scrolling
// NOTE: display contents cannot be changed while scrolling
bool oled_scroll_right(void);
// Scrolls the entire display left
// Returns true if the screen was scrolling or starts scrolling
// NOTE: display contents cannot be changed while scrolling
bool oled_scroll_left(void);
// Turns off display scrolling
// Returns true if the screen was not scrolling or stops scrolling
bool oled_scroll_off(void);
// Returns the maximum number of characters that will fit on a line
uint8_t oled_max_chars(void);
// Returns the maximum number of lines that will fit on the OLED
uint8_t oled_max_lines(void);

!> Scrolling and rotation are unsupported on the SH1106.

SSD1306.h driver conversion guide

Old API

Recommended New API

struct CharacterMatrix

removed - delete all references

iota_gfx_init

oled_init

iota_gfx_on

oled_on

iota_gfx_off

oled_off

iota_gfx_flush

oled_render

iota_gfx_write_char

oled_write_char

iota_gfx_write

oled_write

iota_gfx_write_P

oled_write_P

iota_gfx_clear_screen

oled_clear

matrix_clear

removed - delete all references

matrix_write_char_inner

oled_write_char

matrix_write_char

oled_write_char

matrix_write

oled_write

matrix_write_ln

oled_write_ln

matrix_write_P

oled_write_P

matrix_write_ln_P

oled_write_ln_P

matrix_render

oled_render

iota_gfx_task

oled_task

iota_gfx_task_user

oled_task_user