the chip i'm using is PCF8574 AP and the datasheet gives below value for the address:
For PCF8574A the addressing is:
A2 A1 A0 Dec Hex
L L L 56 0x38
L L H 57 0x39
L H L 64 0x40
L H H 74 0x4A
H L L 75 0x4B
H L H 76 0x4C
H H L 77 0x4D
H H H 78 0x4E
My bad. You are right.
The table however should be 0x39,0x3A,0x3b etc.. ending with 0x3F