Recently I bought an Arduino Mini Pro 328 - 3.3V/8MHz (Sparkfun). I started to program it with this using the following connection:
CP2102 || Mini Pro 3.3v ---------> VCC GND ---------> GND TX ---------> RX RX ---------> TX DTR ---------> GRN
As long as I upload classic blink script or similar, Arduino works well. My project is connect a GPS module and display latitude, longitude and other infos on OLED display like this one. In order to use I need of I2C address, hence I used I2C scanner but it stuck to scanning without show any information. This happens in presence or not of screen (doesn't display either "Not I2C device found"). I checked twice the wiring between OLED and Arduino and I think it's right:
OLED || Arduino SDA ---------> A4 (SDA from official pinout) SCL ---------> A5 (SDA from official pinout) VCC ---------> VCC GND ---------> GND
I can not get on top of this issue. Could you help me, please?
P.S. The programmer is AVRISP mkII, I don't know if is important.