RS pin is used to select the register in the LCD ie,
when RS = 0 , used to send command to the LCD (JHD162A) controller from the P89v51RD2 (command means shift the courser ,blink etc)
When RS = 1 ,used to send Data to the LCD controller (JHD162A) from the P89v51RD2 for displaying on LCD.
RW is used to write or read the information from /to LCD controller
RW should zero when send command /data to LCD
RW one when read some information from LCD (eg: Reading Busy flag)
every command or data send to the LCD we need give a high to low signal to the E
Led+ and Led- is for Back light .
Pin 7-14 is Data pins.
Pin 6-Enable . it should be a Pulse .
pin 5-R/W - To write or Read from LCD Memory.
pin 4-RS- Register select - 1 for Data and 0 for Command .
pin 1- GND
Pin 2 and 3 - 5V and 5V with Var. Pot to Control Display..