Interfacing Atmel AVR with Graphics Liquid Crystal Displays (GLCDs)

AVR SED1520 Library

This is a C-library for avr-gcc/avr-libc to access SED1520-based graphics-LCDs. The modules used to develop the library only support "write to LCD", read-modify- write on the display RAM is not possible. So this Library uses a "framebuffer" which holds the display-content in the AVR's SRAM. For a 122*32 pixel display around 500 Bytes of SRAM are occupied by the buffer. The library does of cause support modules which can be read in "write-only-mode" (tie the R/W-Pin to GND).

The library supports:



The library has been tested with an ATmega32 (8MHZ int. R/C) and an Emerging Displays EW12A03GLY Module (2 SED1520, 122*32 pixels, google for datasheet).

AVR and SED1520 AVR and SED1520
AVR and SED1520 AVR and SED1520

Pictures of the Test-Setup (ATmega32 + EW12A03GLY)


The source-code has been part of my "Will there ever be a request for a commercial license if the source-code is provided"-experiment. This experiment is now halted. The source-code is currently not available. Everybody who has downloaded the source is still bound to the non-commercial license. The only exception are users who have received my permission for a commercial use.

AVR ST7565 Library

This driver for Atmel (8bit) AVR controllers drives graphics LCDs with ST7565 and compatible controllers. The display is driven in "serial mode" (SPI) so just a few IO-lines are needed for the connection. The ST7565 controller is similar to other "modern" LCD controllers usualy found an smaller graphics LCD-modules (typical resolution 128*64 pixels). A similar controller is the S6B1713 which is used on the LCD module that comes with the Atmel DB101 display kit. These controllers offer a so called "electronic volume" which allows to set the contrast by software so there is no need for external analog hardware to control the contrast.

AVR and ST7565
EA DOGM128 with ST7565 controller connected to AVR.

The drivers has the same features as the SED1520 driver mentioned above. In addition functions to control the contrast have been added. I have tested the driver with an EA DOGM128 display from Electronics Assembly and an AVR ATmega32.

The software is not free and available on request. It comes with the full source-code.

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Martin Thomas

68950 hits since August 20, 2005
Last mod.: Friday, 09-Nov-2007 12:27:58 CET