Pin out for common HD44780 (or equivalent) based LCD Displays. This information is not verified to be 100% accurate. Always check the data sheet for your display if you can. If in doubt use an ohm meter to check connections between the HD44780 controller chip and the connector pin.
The most common interface for a character based LCD display is the 14 pin interface. Unfortunately there are two different ways to pin it out.
14 PIN INTERFACE
Seiko - L1672 Dual row
Seiko - L2032,
Hosiden - HLM-3164
Optrex - C-51363GNF, DMC-20171, DMC-20215, DMC-20434, DMC-24227, DMC-32132, DMC-40131, DMC-40218, DMC-50218, DMC-50448
Powertip: PC802-A, PC1601-H (pin 1 in lower right corner), PC1602-I (pin 1 in lower right corner), PC1602-J (pin 1 in lower right corner),
Optrex - C-51515GNF
The pinout below if for the Seiko L1692.
It has a single row of pins along the bottom.
The following is the same connector is along the bottom edge with pin
1 on the left.
The following is the same as the pinout above, but, the connector is
along the top edge of the display with pin 1 on the left side.
Powertip PC1602G, PC1601-L, PC1602-G, PC1602-Q,
15 PIN INTERFACE
VLED - Is the LED Backlight Anode
Alternate 15 PIN INTERFACE
VLED - Is the LED Backlight Anode
Va is the LED backlight anode, LED backlight cathode is tied to GND
16 & 32 PIN INTERFACES
Seiko - L1634, L1671, L1682 & L2034
Powertip: PC1601-A, PC1601-E, PC1601-F, PC1602-C, PC1602-D, PC1604-A (except connector on the bottom edge with pin 1 on the right side), PC1602-G-P2 (two 14 pin connectors, one on top edge, one on bottom edge. Both start with pin 1 on the left side.)
Optrex - DMC-16433 (pins 15 & 16 are for EL backlight), DMC-20261, DMC-20481; DMC-50097 (pins 15 & 16 are no connect); DMC-20203, DMC-40202 & DMC-40267 (signals on pins 15 & 16 are reversed)
The pinout below also works on several Seiko displays including the L1634, L1671, L1682 & L2034. These Seiko displays have two sets of connection pins. They have pins 1-16 on the top of the display and pins 17-32 on the bottom of the display. They are wired in parallel so you can use either one.
VA is LED backlight Anode
VC is LED backlight Cathode
VLC is 0 to -7V on DMC-50097
VLC is 0 to -4V on DMC-20203
18 PIN INTERFACE
Used on the L40x4 (4x40)
Optrex - DMC-40457
On DMC-40457, signals on pins 17 & 18 are reversed.
E1 is the enable signal for the first HD44780 controller.
E2 is the enable signal for the second HD44780 controller.
VA is the LED backlight Anode.
VC is the LED backlight Cathode.
22 PIN INTERFACE - (4 Bit mode only)
Used on the Seiko CG550001 and other displays
The LED back light on the CG550001 has a forward drop of 4.1V at a current of 40 mA. Connect LED+ to +5V through a 22 Ohm resistor.
E - stands for enable. A high level on this pin enables the display.
RW - stands for Read/Write. A high level signals a read. A low level signals a Write.
RS - stands for Register Select. A high level signals Data input. A low level signals Instruction code input.
VLC - Liquid Crystal Driving voltage. Connect this to the wiper of a 20K pot. The other two leads of the pot connect to VDD and Ground. In some cases the bottom end needs to connect to a negative voltage instead of ground.
VDD - This is the +5V (+/- 5%) input pin.
Index of all current Seiko Instruments Inc. Character LCD displays. SII Character Modules
Index of all current Seiko Instruments Inc. Graphic LCD displays. SII Graphic Modules
If you are going to do any interfacing to a HD44780 based LCD display you NEED the data sheet. You can find it here http://www.eio.com/hd44780.pdf
There is an excellent app. note from Hantronix on connecting a display up to a PC's parallel port. click here
I believe that the HD66702, HD66710, HS66712S/U, KS0063, KS0066B, KS0066U and KS0070B are equivalent to the HD44780 controller.
ZLCD download site for Graphical LCD data sheets.
Check out this site for info on initializing and programming a HD44780 based display. click here
Another web page with excellent information on LCD displays click here
This page was last updated on April 18, 2003
Send any comments & suggestions to [email protected]
Please don't send me questions.
Questions should be posted on the EIO LCD Forum.
Don't forget to check their current LCD offerings.
New Seiko G321D Displays available. G321DX5R1AC.