SSD1306 dual I2C display

Dual I2C display in One Oled

 

fm4dd commented on 16 Jun 2019

No description provided.   Author fm4dd commented on 16 Jun 2019 I am running two SSD1306 128x64 OLEDs on a single I2C bus with separate addresses (0x3C and 0x3D). They work as listed in issue #434. However unless the buffer fully cleared after writing to one display, updating them independently does not work. I believe the buffer pointers are both written into, but let me first explain the issue on a few examples. Example 1: `#include <Wire.h> #include <U8g2lib.h> U8G2_SSD1306_128X64_NONAME_F_HW_I2C dleft(U8G2_R0); U8G2_SSD1306_128X64_NONAME_F_HW_I2C dright(U8G2_R0); void setup() { dleft.setI2CAddress(0x3C * 2); dright.setI2CAddress(0x3D * 2); dleft.begin(); dright.begin(); dleft.clearBuffer(); dright.clearBuffer(); } void loop() { // write ABC to left display dleft.clearBuffer(); dleft.setFont(u8g2_font_inr19_mr); dleft.drawStr(0,32, "ABC"); dleft.updateDisplay(); // write DEF to right display //dright.clearBuffer(); dright.setFont(u8g2_font_inr19_mr); dright.drawStr(64,32, "DEF"); dright.updateDisplay(); delay(500000); }` In this case, the intention is to write ABC to display-1 (left, I2C 0x3C), and DEF to display-2 (right, I2C 0x3D). It only works after I uncomment the dright.clearBuffer() line, but that should not be necessary. The right display gets the content from the left display as well, even though that wasn't intended.    fm4dd closed this on 16 Jun 2019   Owner olikraus commented on 20 Jun 2019 Yes, the memory is shared between the displays.