Dear Sir,

The LCD works fine as long as the power is supplied non-stop. However, when I turn LCD power off and turn on again, LCD displays two line black square forever, similar to power on first time. The power of PIC18F8520 is always on (never off). The definition of LCD is as follows:

DEFINE LCD_EREG PORTA
DEFINE LCD_EBIT 2
DEFINE LCD_LINES 4
DEFINE LCD_RSREG PORTA
DEFINE LCD_RSBIT 0
DEFINE LCD_DREG PORTF
DEFINE LCD_DBIT 0
DEFINE LCD_BITS 8

Your help and advice would be very much appreciated.

Yuantu