@dalmator:

Also, wie gesagt ist die Pinbelegung egal.

Code:
////// PCF8574p PINS

#define LD4			0				// Pin to Data Bus 4
#define LD5			1				// Pin to Data Bus 5
#define LD6			2				// Pin to Data Bus 6
#define LD7			3				// Pin to Data Bus 7

#define LRS			4				// Pin to RS Pin (Register Select)
#define LRW			5				// Pin to Read/Write Pin
#define LEN			7				// Pin to Enable Pin