U8G2_R0 and I2C address

[jandemna]

My .96" OLED display (2 euro:) worked directly with defined line below attached to D1 MINI. Thanks olikraus for the nice lib!!

U8G2_SSD1306_128X64_NONAME_F_SW_I2C u8g2(U8G2_R0, /* clock=/ SCL, / data=/ SDA, / reset=*/ U8X8_PIN_NONE); // All Boards without Reset of the Display

What is U8G2_R0 and where is it defined? Looked for it everywhere, but not successful. Does it define the I2C address or is this fixed in SSD 1306?

[olikraus]

U8G2_R0 (and friends) are described here: https://github.com/olikraus/u8g2/wiki/u8g2reference#carduino-example

Declarations are here:

u8g2/csrc/u8g2.h

Lines 435 to 447 in 4486047

	extern const u8g2_cb_t u8g2_cb_r0;
	extern const u8g2_cb_t u8g2_cb_r1;
	extern const u8g2_cb_t u8g2_cb_r2;
	extern const u8g2_cb_t u8g2_cb_r3;
	extern const u8g2_cb_t u8g2_cb_mirror;
	extern const u8g2_cb_t u8g2_cb_mirror_vertical;
	#define U8G2_R0 (&u8g2_cb_r0)
	#define U8G2_R1 (&u8g2_cb_r1)
	#define U8G2_R2 (&u8g2_cb_r2)
	#define U8G2_R3 (&u8g2_cb_r3)
	#define U8G2_MIRROR (&u8g2_cb_mirror)
	#define U8G2_MIRROR_VERTICAL (&u8g2_cb_mirror_vertical)

Usually the lowest available I2C address is used as default in U8g2. Any other I2C address can be assigned with https://github.com/olikraus/u8g2/wiki/u8g2reference#seti2caddress

[jandemna]

Thanks, very clear. I Need to improve on my search (tools).....and RTFM