Hitachi HD44780 User Manual

1
LCD module
Hitachi HD44780 controller
Hitachi
HD44780
controller
and compatible
Main features
z 5x8 character dot matrix display
z 80x8-bit display RAM
z 64x8-bit character generator RAM
z 4-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
t
cycE 1000 ns 500 ns E cycle
t
AB 60 ns 40 ns address setup
t
AH 20 ns 10 ns address hold
t
DBW 195 ns 80 ns data setup (write)
t
H 10 ns 10 ns data hold (write)
t
DHR 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

Hitachi HD44780 Specifications

General

Type	LCD controller
Interface	Parallel
Data Bus Width	4-bit or 8-bit
Operating Voltage	4.5V to 5.5V
Package	DIP, SOP
Display Lines	1 or 2
Character Size	5x8 dots or 5x10 dots
Temperature Range	0°C to +50°C (Standard) / -20°C to +70°C (Extended)
Character Font	5x8 dots
Character Code	ASCII
Display Modes	Display ON/OFF, Cursor ON/OFF
Instruction Set	Standard HD44780 instruction set
Display Format	Character display

Summary

Interface

Vo Contrast Adjustment

Pin for adjusting the display contrast level.

RS Register Select

Register Select pin to differentiate between command and data.

R/W Read / Write

Read/Write pin to select data read or write operation.

E Enable signal

Enable signal to latch instructions or data into the module.

Quick guide for standard write

Set RS and data

Configure the RS pin and load the data for writing.

Set E

Activate the Enable signal to latch the data.

Wait at least PWEH

Observe the minimum E pulse width (PWEH) requirement.

Clear E

Deactivate the Enable signal after the pulse.

Wait tcyce

Wait for the minimum E cycle time (tcyce) before next operation.

ET-LCD port on ET-BASE AVR

ET-CLCD pin 1-7 Mapping

Mapping of LCD control and data pins to AVR microcontroller pins.

ET-CLCD pin 8-14 Mapping

Mapping of remaining LCD pins to AVR microcontroller pins.

Internal Reset Procedure

Display Clear

Step 1: Clears the entire display content.

Function Set

Step 2: Configures interface, lines, and character font.

Display On/Off Control

Step 3: Sets display, cursor, and blinking states.

Entry Mode Set

Step 4: Defines cursor movement and display shift.

Initializing by Instruction (4-bit Interface)

Power On Sequence

Initial steps after power-on, including wait times.

Function Set (8-bit)

First function set command, assuming 8-bit interface.

Function Set (4-bit)

Second function set command, switching to 4-bit interface.

Display Clear

Command to clear the display content.

Entry Mode Set

Command to set entry mode parameters.

Initializing by Instruction (8-bit Interface)

Power On Sequence

Initial steps after power-on, including wait times.

Function Set (8-bit)

First function set command, configuring for 8-bit interface.

Display Clear

Command to clear the display content.

Entry Mode Set

Command to set entry mode parameters.