HD44780 character LCD module interface pinout

This 16×2 character module exposes the parallel command and data bus used by the HD44780 controller family.

Optrex DMC16230-AAE-DW

14 contacts Current package

Optrex / Hitachi · Fourteen-contact LCD module interface.

Optrex DMC16230-AAE-DW pinout

Optrex DMC16230-AAE-DW

Contact sequence in the module drawing. Identify the board’s pin 1 marker before wiring.

Selected pin details

3 · VEE

Input · Inputs

LCD contrast-bias input. Use a potentiometer between VCC and VSS, wiper to VEE.

Optrex DMC16230-AAE-DW No. 2000-0270, § 4.1

Electrical limits · Link to this pin

All 14 pins

Pin	Signal	Direction	Function
1	VSS Return	Return	Logic supply and controller ground.
2	VCC Supply	Supply	5 V logic supply.
3	VEE Input	Input	LCD contrast-bias input. Use a potentiometer between VCC and VSS, wiper to VEE.
4	RS Input	Input	Low selects the instruction register. High selects the data register.
5	R/W Input	Input	Low selects writes. Ground for a write-only host.
6	E Input	Input	Enable input. The module latches written data at the falling edge.
7	DB0 Bidirectional	Bidirectional	Parallel data bit 0. Leave open in 4-bit mode.
8	DB1 Bidirectional	Bidirectional	Parallel data bit 1. Leave open in 4-bit mode.
9	DB2 Bidirectional	Bidirectional	Parallel data bit 2. Leave open in 4-bit mode.
10	DB3 Bidirectional	Bidirectional	Parallel data bit 3. Leave open in 4-bit mode.
11	DB4 Bidirectional	Bidirectional	Parallel data bit 4. Used in both bus widths.
12	DB5 Bidirectional	Bidirectional	Parallel data bit 5. Used in both bus widths.
13	DB6 Bidirectional	Bidirectional	Parallel data bit 6. Used in both bus widths.
14	DB7 Bidirectional	Bidirectional	Parallel data bit 7. Used in both bus widths.

Signal assignments

4-bit parallel bus

Transfer the upper nibble first, then the lower nibble. With R/W low, wait for command completion in firmware.

8-bit parallel bus

One enable pulse transfers all eight bits. For reads, release the host data outputs before raising E.

Electrical limits

Parameter	Limit	Conditions and source
Module logic supply5 V nominal	5 V nominal	Use the module specification for logic and contrast limits. Optrex DMC16230-AAE-DW No. 2000-0270, §§ 2 and 4.2
Contrast potentiometer10–20 kΩ	10–20 kΩ	Connect between VCC and VSS with its wiper at VEE. Optrex DMC16230-AAE-DW No. 2000-0270, § 4.2

Models and documents

The pin map follows the Optrex DMC16230-AAE-DW 14-contact module. Optrex permits a controller equivalent to HD44780. Backlit modules and bare controller packages use their own mechanical drawings.

DMC16230-AAE-DW: 16 characters × 2 lines, fourteen electrical contacts.

Optrex DMC16230-AAE-DW No. 2000-0270· Archive copy of Optrex’s module specification. See §§ 2 and 4.
Hitachi HD44780U data sheet· Distributor copy of the Hitachi controller data sheet. Bus timing, instruction table and 4-bit initialization.
Source register· Document revisions, applicable order codes, consulted sections and available file checksums.