Thank you SmashedTransistors!
I have ordered this module:
It is the same as here (Backside viewing image available):
The module can be switched to I2C by desoldering the resistor on the back of the module and moving it to the I2C position. The screen printing shows the exact positioning of these solder tabs.
The wiring is then as follows:
GND: power ground --> GND
VCC: --> VDD
D0: CLK clock (sdk/scl k) --> PB8
D1: MOSI data (sda) --> PB9
RST: reset --> VDD
DC: data/command --> GND
CS: chip select signal --> GND
I also used the two resistors 10k as mentioned above.
In the object OLED128x64 set the type SH1106 and the I2CADDR to 0x3C.
And to all beginners:
To avoid errors during compilation the object tiar/disp/scope has to be included! Even if it is not used and you only display text lines.
Ingenious thing - thanks!