U8g2: Lack of SH1106 chip driver in compare to

[VitaliGN]

As I understand the u8g2 library is a new version of u8glib. But I have an 1.3 inch OLED display which has a SH1106 chip driver with 4 pin I2C bus. So my issue is that u8glib has this constructor call initialization in line 103 (see link below), but u8g2 has only 2 SPI constructor calls in commented area of it's helloworld example. If I use SSD1306 then I have a corrupted line on the side of display.

https://github.com/olikraus/U8glib_Arduino/blob/master/examples/HelloWorld/HelloWorld.ino
line 103 = U8GLIB_SH1106_128X64 u8g(U8G_I2C_OPT_NONE); // I2C / TWI

[JamesGKent]

there are many constructors for SH1106 see here:
https://github.com/olikraus/u8g2/wiki/u8g2setupcpp#sh1106-128x64_noname

and below that are others depending on make and resolution.

[VitaliGN]

Thank you I will try it when I get to my breadboard

[olikraus]

Yes, the examples contain only a small fraction of the constructors.

[VitaliGN]

I want to use this constructor U8G2_SH1106_128X64_NONAME_F_HW_I2C(rotation, [reset [, clock, data]]), but compiler highlights reset, clock and data by red color and saying that it is undefined, should I remove brackets and use SCL, SCK pins?

(thank you for your support, I will come back tomorrow)

[olikraus]

Yes, replace this with Arduino pin numbers.

[VitaliGN]

good morning,

U8G2_SH1106_128X64_NONAME_F_HW_I2C(rotation, reset, 21, 20);

seems no warnings, but I noticed that all constructors have "reset" parameter. but my I2C display has only VDD, GND, SCL, SDA. is it ok that there is a "reset" parameter?

[olikraus]

If reset is not the, just use U8X8_PIN_NONE.

Note, that the i2c pins are usually fixed. This means, the last two arguments are only required for ESP based board s which allow any pins to be used.

[VitaliGN]

I have just noticed that there are default values in the header files for each parameter, I think I start to understand. it is because it has a default value of "U8x8_pin_none". phew a little step further

[VitaliGN]

I wrote right after you, ok, so considering what you wrote about last two arguments - I could leave only the rotation parameter? Oh, by the way the rotation parameter should be left as "rotation" or I should put some number as "0" there?

[VitaliGN]

U8G2_SH1106_128X64_NONAME_F_HW_I2C(rotation, reset, 21, 20);
hm, now it again highlights commas saying that there should be ')' after "rotation" and numbers 21 and 20 saying that there should be identifier. a minute ago it was ok, now again.

[JamesGKent]

the options for the rotation argument are here:
https://github.com/olikraus/u8g2/wiki/u8g2setupcpp#rotation

so assuming you want the default no rotation, and using hardware i2c your constructor should be:
`U8G2_SH1106_128X64_NONAME_F_HW_I2C(U8G2_R0);

[VitaliGN]

cool, I understand, if I use HW in constructor I logically do not need to put 21 and 20 pins because they should be defined by HW, and if I would want to change to another pins I should have used the SW instead of HW!

[VitaliGN]

my mistake also was that I did not use the "u8g2" before brackets to initialize the display class
U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0);

[JamesGKent]

ah, i didn't spot that... so assuming all is working now are you happy to close this issue?

[olikraus]

:-)

[VitaliGN]

one more question - would it be possible to use two displays and make it so:
U8G2_SH1106_128X64_NONAME_F_HW_I2C Oled1(U8G2_R0);
U8G2_SH1106_128X64_NONAME_F_HW_I2C Oled2(U8G2_R0);
?
seems no mistake in compiler but I can not check it right now with displays (they are far from me)

[olikraus]

Yes, this is possible, but you need to assign different i2c client addresses. Usually there are solder bridges on the OLED to modify this address. In U8g2, there is a command to change the address.

[VitaliGN]

Would it be ok to use it like that:

U8G2_SH1106_128X64_NONAME_F_HW_I2C Oled1(U8G2_R0);
U8G2_SH1106_128X64_NONAME_F_HW_I2C Oled2(U8G2_R0);

void setup()
{
    Oled1.begin();

    Oled2.setI2CAddress(0x78); // it has to be before the begin? the number is not exact I just imagined it but I have seen that OLED has those addresses on the back side
    Oled2.begin();
}

[VitaliGN]

yes, Reference says that setting address should be before the begin()
https://github.com/olikraus/u8g2/wiki/u8g2reference#seti2caddress

[VitaliGN]

I am lacking questions about OLED initialization now, I will have to check all this in the evening with the board. hope now after such a great support I understand the main point and this issue can be closed

[olikraus]

Let us know if you have further questions.