I2C LCD with PCF8574 hangs the firmware
I'm using repetier firmware 0.92.8 on a Gen7 1.4 with ATMega 1284P at 20Mhz. All works fine, included the SD card but I'm not able to use the 20x4 LCD display with the I2C protocol and PCF8574.
I defined UICONFIG_CONTROLLER in Configuration.h and in UIconfig.h:
UI_DISPLAY_I2C_ADDRESS 0x40 (the A0 A1 A2 pins of the PCF8574 are a ground).
I tried also the address 0x20, 0x21, 0x41....
I put also 2 pull-up resistor on the SCL and SDA lines as the I2C specifications but when I load the firmware with this configuration, the firmware hangs and no USB connection is available.
Can you help me ?
Thanks in advance