INFORMATION FILE FOR HD44102 20x4 CHARACTER LCD
===============================================

             (C) ARNE ROSSIUS 2006
          http://www.elektronik.de.vu



HD44102 LCD PINOUT

      Parallel
Pin     Port     Function
-------------------------------------------
  1     14       CS2
  2     17       CS1
  3     18~25    GND
  4     -        V_CC (+5V)
  5     -        V_LCD (approx. -5V)
  6     16       RS (Command = 0, Data = 1)
  7     18~25    R/W'
  8     1        E
  9     2        D0
 10     3        D1
 11     4        D2
 12     5        D3
 13     6        D4
 14     7        D5
 15     8        D6
 16     9        D7



HD44102 COMMANDS

Display off:    0x38
Display on:     0x39
First Page:     0x3E + (Page * 0x40)
Start Address:  (Page * 0x40) + Y
Auto-Decrement: 0x3A
Auto-Increment: 0x3B

Data: each byte is a column of 8 pixels (7 pixels for the character and one for
the cursor). MSB = cursor pixel. Note that address Y=0 is on the right, so
increment means writing data from the right to the left. Usually you will want
to set the Y address to 49 and then write data from left to right. Also note
that there is no "clear display"-command.
A datasheet with the complete command list is available at
http://www.datasheetarchive.com/search.php?q=HD44102CH



HD44102 LCD MEMORY MAP

   Contr. 1  Contr. 2
  /^^^^^^^^\/^^^^^^^^\
,----------------------,
| AAAAAAAAAAAAAAAAAAAA | <- Page 0
| AAAAAAAAAAAAAAAAAAAA | <- Page 1
| AAAAAAAAAAAAAAAAAAAA | <- Page 2
| AAAAAAAAAAAAAAAAAAAA | <- Page 3
'----------------------'
  \________/\________/
  49......0 49......0    <- Y address

Controller 1 (select with CS1 = High) controls the left side of the LCD (first
10 characters in every line), controller 2 controls the right side. It might be
a good idea to enable both controllers during initialisation so you only need to
send the commands once.