I used this with a Microchip PIC development board to interface to a 20x4 LCD display. With only 4 wires (including 2 for power) it's simple to set up and uses far fewer ports than the standard LCD parallel interface. As delivered the address pads A0 A1 and A2 are open but pulled high - so the I2C address is 0x4E. Ports P7,P6,P5,P4 of the PCF8574 interface to DB7,DB6,DB5,DB4 of the LCD Display. Port P3 is hard-wired to the backlight via a transistor: 1 = on / 0 = off. It's great that the backlight can be switched on and off via software with no additional hardware required. Port P2 is the display bit clock : E = 1 -> E = 0 active. Port P1 is R/W hardware Read/Write bit hardware : Read = 1 / Write = 0, so reading from the LCD display is possible, if required. Port P0 is RS Register Select : CmdReg = 0 / DataReg = 1. Display driver is HD44780 compliant. A great buy! I won't be interfacing to an LCD in future without it.

I used this with a Microchip PIC development board to interface to a 20x4 LCD display. With only 4 wires (including 2 for power) it's simple to set up and uses far fewer ports than the standard LCD parallel interface. As delivered the address pads A0 A1 and A2 are open but pulled high - so the I2C address is 0x4E. Ports P7,P6,P5,P4 of the PCF8574 interface to DB7,DB6,DB5,DB4 of the LCD Display. Port P3 is hard-wired to the backlight via a transistor: 1 = on / 0 = off. It's great that the backlight can be switched on and off via software with no additional hardware required. Port P2 is the display bit clock : E = 1 -> E = 0 active. Port P1 is R/W hardware Read/Write bit hardware : Read = 1 / Write = 0, so reading from the LCD display is possible, if required. Port P0 is RS Register Select : CmdReg = 0 / DataReg = 1. Display driver is HD44780 compliant. A great buy! I won't be interfacing to an LCD in future without it.

I used this with a Microchip PIC development board to interface to a 20x4 LCD display. With only 4 wires (including 2 for power) it's simple to set up and uses far fewer ports than the standard LCD parallel interface. As delivered the address pads A0 A1 and A2 are open but pulled high - so the I2C address is 0x4E. Ports P7,P6,P5,P4 of the PCF8574 interface to DB7,DB6,DB5,DB4 of the LCD Display. Port P3 is hard-wired to the backlight via a transistor: 1 = on / 0 = off. It's great that the backlight can be switched on and off via software with no additional hardware required. Port P2 is the display bit clock : E = 1 -> E = 0 active. Port P1 is R/W hardware Read/Write bit hardware : Read = 1 / Write = 0, so reading from the LCD display is possible, if required. Port P0 is RS Register Select : CmdReg = 0 / DataReg = 1. Display driver is HD44780 compliant. A great buy! I won't be interfacing to an LCD in future without it.

I bought some of these and found out that there are different models which need different pin configurations. Here is a beginners guide for the ones from Bangood: http://safe-power.appspot.com/i2c-en.html You need to download one library, and you are ready to enjoy LCDs on your arduino with only 2 Arduino pins occupied (plus GND and VCC). This little board saves you time and pins :-)

I bought some of these and found out that there are different models which need different pin configurations. Here is a beginners guide for the ones from Bangood: http://safe-power.appspot.com/i2c-en.html You need to download one library, and you are ready to enjoy LCDs on your arduino with only 2 Arduino pins occupied (plus GND and VCC). This little board saves you time and pins :-)

I bought some of these and found out that there are different models which need different pin configurations. Here is a beginners guide for the ones from Bangood: http://safe-power.appspot.com/i2c-en.html You need to download one library, and you are ready to enjoy LCDs on your arduino with only 2 Arduino pins occupied (plus GND and VCC). This little board saves you time and pins :-)