sorry for the mess in my previous posting.

you can connect the LCD data bus directly to the 8051's data bus. but it is a good practice to buffer through a 74HCT245.follow the ckt below. a 2 input NAND gate will do

LCD --- 8051
E = !((/WR nand /RD ) nand ( LCD_CS ))

R/W = /WR

C/D = A0

you can use the spare NAND to invert the /LCD_CS from the address decoder.
the /LCD_CS is memory mapped. if you are using '245, control the data direction by using /WR or /RD