ESP8266 Community Forum

- Sun Dec 06, 2015 10:12 am #35805 Has any one gotten this working withthe PCF8574AT board? Particularly this board -http://www.aliexpress.com/item/Hot-1602-16x2-HD44780-Character-1602-LCD-Module-Display-5V-Serial-IIC-I2C-TWI-For-Arduino/32370241702.html? I tried 0x3F for the address but it doesn't seem to work.

Thanks for any help!

- Sun Dec 06, 2015 10:21 am #35806 Are you sure the address is 0x3F ? that depends if the A2/A1/A0 is set to HIGH, if the are set to LOW, the address should be 0x38. (also, if the chip is older PCF8574 instead of PCF8574A, the address would be 0x20). Beware also that some libraries assume and some other not that addresses are shifted by 1 bit for R/W, so, 0x38 would be seen as 0x70.