This is shown in the photo below. State3 may occur, for example, if a prior control was aborted after sending only the first 4 bits of a command while the LCD was in 4-bit mode. Two versions of the ROM have been developed: Those without backlights may have only 14 pins, omitting the two pins powering the light. Home Questions Tags Users Unanswered. The module that we are using is a 16 character x 2 line display that we stock over here. A limited number of custom characters can be programmed into the device in the form of a bitmap using special commands.

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All articles with unsourced statements Articles with unsourced statements from June Commons category link is on Wikidata Commons category link is on Wikidata using P I love the quality of your photos too. Larger custom sizes are made with 32, 40 and 80 characters and with 1, 2, 4 or 8 lines. Pinout The module that we are using is a 16 character x 2 line display that we stock over here.

Using an extension driver, the device can display up to 80 characters. These characters have to be written to the device each time it is switched on, as they are stored in volatile memory.


I have a feeling that my timing isn’t quite correct with the assembly code, just not too sure where or what to fix The tables below show the instruction set and character table.

HD based display modules also have a 4 bit interface mode. Timing with the older HD modules can be tricky. It would appear that you have “issues” in your code. My thanks and gratitude for such an excellent explanation of how 16 char LCDs work which even I can understand. The Hitachi HD LCD controller is limited to monochrome text displays and is often used in copiersfax machinesllcd printersindustrial test equipment, networking equipment, such as routers and storage devices.

microprocessor LCD, Microchip PIC LCD, HD

This is an excellent approach to operate the device with switches first. A web surf for info on the LCD brought me here.

Absolute ; ; Files required: Blocks implies contrast voltage set all the way up but not characters. Reinderien 4 Normally you would drive an LCD display from a microcontroller, computer or similar device.

HD Character LCD Displays – Part 1 – Protostack

Thank you for these pages. Under this mode the data or command is transferred to the module using 2, 4 bit nibbles.

Non-LED backlights often require higher voltages. In the next part we will discuss how to hookup the module to a microcontroller and get it to do the hard work for you. This will be discussed in more detail below. Go to the shop. The enable button assemblt a 10nF capacitor to de-bounce it.


I hated that IC, with its 8K memory paging, which needed extra code. Leave a reply Click here to cancel the reply Your email address will not be published. Selecting 4-bit or 8-bit mode requires careful selection of commands. The data sheet does not say much about the contrast voltage; there are a few mostly older, I think displays that need a negative contrast voltage. By using our site, you acknowledge that you have asdembly and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Hitachi HD44780 LCD controller

Already have an account? Sign up using Facebook. The Register Select and data lines are pulled down using a 10K resistor and when the assrmbly switch is closed, those lines go high. Very nice job with the overall presentation.