Hitachi HD44780 User manual

1
LCD module
Hitachi HD44780 controller
Hitachi
HD44780
controller
and compatible
Main features
z5x8 character dot matrix display
z80x8-bit display RAM
z64x8-bit character generator RAM
z4-bit or 8-bit interface
Interface
1VssGND
2 VDD Vcc (+5V ± 5%)
3 Vo Contrast Adjustment
4 RS Register Select
5 R/W Read / Write
6 E Enable signal
7-14 DB0-DB7 Data Bus
Timing
Item
min min
description
Item
@ 2.7-4.5V @ 4.5-5.5V
description
PWEH 450 ns 230 ns E hold
tcycE 1000 ns 500 ns E cycle
tAB 60 ns 40 ns address setup
tAH 20 ns 10 ns address hold
tDBW 195 ns 80 ns data setup (write)
tH10 ns 10 ns data hold (write)
tDHR 5 ns 5 ns data hold (read)
Quick guide for standard write
1. Set RS and data
2. Set E
3. Wait at least PWEH
4. Clear
E
5. Wait tcycE
(initialization is different!!)
ET-LCD port on ET-BASE AVR
ET-CLCD pin 1 2 3 4 5 6 7891011121314
signal GND +Vcc Vo RS R/W EN D0 D1 D2 D3 D4 D5 D6 D7
AVR pin GND +Vcc (LCD
ADJ) PG4 GND PD7 GND GND GND GND PG0 PG1 PG2 PG3

2
4-bit interface
zbus lines DB0-DB3 disabled
z4 high order bits followed by 4 low order bits
Display addressing
Display position 1 2 3 4 5 … 39 40
DDRAM address
(row 1) 00 01 02 03 04 … 26 27
DDRAM address
(row 2) 40 41 42 43 44 … 66 67
Instruction Set
1. Designate functions
(display format, data length etc.)
2. Set internal RAM address
Dt t f
3.
D
a
t
a
t
rans
f
e
r
4. Miscellaneous functions
s
6
instuctions
1 tclock tick @ 16MHz = 62.5 n
s
1us = 1000us/(62.5ns/instr) = 1
6
37us = 592 instructions
Instructions - Legend Internal Reset Procedure
1. Display clear
2. Function set:
DL = 1; 8-bit interface data
N = 0; 1-line display
F = 0; 5 x 8 dot character font
3. Display on/off control:
D = 0; Display off
C = 0; Cursor off
B = 0; Blinking off
4. Entry mode set:
I/D = 1; Increment by 1
S = 0; No shift

3
y
Instruction
terface
Initializing b
y
4-bit in
y
Instruction
terface
Initializing b
y
8-bit in