This is my complete parameter chain of avrdude: hex file of my C program to my atmega328p with the following fuse configuration. Further I'm using avrdude to uploaded the compiled. In order to program my atmega328p I'm using an Arduino Uno with the 'ArduinoISP' sketch installed on it. According to the datasheet of the port expander (pcf8574) it requires an i2c SCL of 100 KHz to work properly, so I made my changes undone and set it back to 100 KHz. Today I changed the SCL from 100000UL (100 KHz) to 400 KHz and 1.7 MHz, but none of these configurations worked. While( !(TWCR & (1<order to ensure there's no hardware issue I tested the i2c communication with the LiquidCrystal_I2C library from the Arduino IDE and it all worked fine. It seems that the TWINT flag never changes and therefore causes the program to hang in the while-loop. I found out that my code hangs in the following while-loop in the i2c_start function. The pin mapping and wiring shouldn't be the problem. P3 -> not connected to any of the lcd pins I already checked the pin mapping between the lcd display and the attached port expander by using a multimeter.

I'm trying to use a LCD2004A/PCF8574T with an atmega328P but after hours of debugging I still can't get it to work. but my and my backlight is npn transistor so turned on is PCF_P7=1 Pcf8574 adress is 0x20, and my connection is like this For You it's maybe 5minutes of work, can you provide me with hex file just to burn it to my mcu? I'm trying to get this to work just to know does my pcf8574t chip is still live at all because i'm also trying to controll lcd on such was using some other programming method. To be clear i really don't understand all this stuff what it mean and avr studio is quite strange to me, but even i know that my pin connections are different I could fix that later based on Your previous advice for lcdpcf8574.h.įor now i don't know how to get compile ok. i keep getting some compile errors about LCD_DISP_ON_BLINK and 2, or 3 other lines. I also get solid block of squares in one line only but I can't get this even to compile.

Adc lcd16x2 codevision avr