• Introduction to the HD44780 Module
• Key Software Capabilities
• Documentation for the HD44780 Module
• Downloading the HD44780 Module

The HD44780 Module is designed to allow the user to simply interface microcontrollers with alphanumeric LCD displays that use an HD44780 based LCD display controller, or one of the many clones that are available. The module is abstracted into several sub-modules. At the highest level there is the HD44780 driver itself that generates all of the HD44780 specific read/write requests. These requests are then passed to an LCD interface driver that handles the hardware interface data transfers to which the display is connected. The LCD interface is microcontroller independent (for Microchip's products) and can be modified to support any available hardware interface, such as a bit-banged GPIO peripheral or a memory mapped parallel interface peripheral. The HD44780 driver and LCD interface driver can also support multiple hardware interfaces in order that several alphanumeric displays can be connected to the same or different hardware interfaces on the microcontroller. The design of the HD44780 driver is generic i.e. it is not targeted at any specific processor architecture or family of microcontrollers, allowing it to be used anywhere. The efficiency of the code and its performance is, therefore, very much dependant on the C compiler used to compile the code. The LCD interface currently included is tied to a bit-banged GPIO interface for Microchip microcontroller products..

Key Software Capabilities

• Support for up to 16 independent HD44780 chipsets

• Support for up to 16 different hardware interfaces

• Support for 4-bit and 8-bit interface configurable for each hardware interface

• Fully re-entrant on pre-emptive systems

• Hardware interface mutex to ensure that only one software thread can use common hardware resource

• All HD44780 instructions are supported

• Support for creating self-defined characters in the CGRAM

• "Instruction Initialisation" implemented for the following alphanumeric LCD controllers: 

• HD44780U

• ST7066U

• S6A0069

• KS0066U

• NT7603 (Novatek)
• Support to correct swapped high-nibble/low-nibble during 4-bit mode data read, when confronted

• All memory allocation handled by the module's user

• Very small RAM footprint

• Fully portable ANSI C in the upper HD44780 module implementation, suitable for embedded microcontroller systems

The documentation for the HD44780 Module and the associated available LCD Interface Module are to be found on http://kenai.com/projects/hd44780-module/documentation

A fully tested release is always available under the downloads link on http://kenai.com/projects/hd44780-module/downloads. Currently there is no stable release as this module is still under development

Return to HD44780s project home page.