You did not say if you actually turned ON the display... most LCD Display controllers require that you send a "Display ON" command before thay actually begin driving the display...
eg: for the TL0313, i use:
and for the PCF8548:
(0xAE) Display Off
(0xC0) SHL Select
(0xA0) ADC Select
(0xA3) LCD Bias Select
(0x2C) Power Control
(0x27) Regulator Resistor Select
(0x81) Set Reference Voltage Mode
(0x0C) Set Reference Resistor
(0xA6) Reverse Display On/Off
(0x40) Initial Display Line
(0xAF) Display On
as you can see, Both LCDs require the LCD to be turned ON...
(0x00) many command bytes follow - see pcf8548 data sheet
(0x29) Function Set => MX=0, MY=1 (Vertical Mirror), PD=0 (Chip Active), V=0 (Horizontal Addressing), H=1 (extended set command)
(0x04) Temperature Coefficient 0
(0x15) bias = 5
(0x80) Vop (Unused)
(0x0C) DO=1 (LSB on Top), TRS=0 (top rows are not mirrored), BRS=0 (bottom rows are not mirrored)
(0x28) Function Set => MX=0, MY=1 (Vertical Mirror), V=0 (Horizontal Addressing), H=0 (normal command set)
(0x0C) Display control => D and E = 10 (normal lcd mode) (01=all display segments on) (11=inverse video mode)
--->>> check to see if your one does....