Questions tagged [hd44780]

The HD44780 is a controller/driver IC for dot matrix character LCDs.

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49 views

Can anyone shed light on why a I2C PCF8574 LCD driver would only be using I2C 'read' operations to 'write' to the device?

I am trying to understand a simple I2C driver for a HD44780 with soldered PCF8574 daughter board, I'm still relatively new to electronics engineering (read: 20 years out of date), but an old hand with ...
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2answers
227 views

Looking for a way to re-program 16x2 LCD display EEPROM font

Some time ago I've seen this topic - asking where does the fonts stored in 16x2 (1602) LCD display. Does a 16x2 LCD display has its own EEPROM? I'm really interested in this, and didn't find any ...
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35 views

Groove LCD RGB I2C protocol

Devices: RapberryPi 3 Model B+ GrovePi+ Grove LCD RGB As a learning exercise, I'd like to write a driver for the LCD listed above. I'm using the HD44780 instruction set as reference, and can ...
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4k views

Terminology - VDD vs VSS?

What is the correct voltage terminology for VDD and VSS? I've been installing a Winstar WEH001602D OLED and was struggling until I realised that it appears to have pins 1 and 2 reversed compared to ...
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528 views

HD44780 LCD Driver for STM32F3

I am trying to interface an HD44780 LCD with an STM32F3 MCU. I'm using examples from the website http://controlsoft.mandela.ac.za/STM32F3-Discovery-Board/Example-programs/HD44780-LCD-(16x2-LCD) it ...
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1answer
525 views

PIC18F452 interfacing with HD44780 LCD in assembly

I have been trying to get a Hitachi HD44780 LCD to work with my PIC18F452 for a few days now, with no luck. I have tried moving the data lines to different ports on the microchip, I've tried ...
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2answers
365 views

Is this 20x2 character display broken?

Recently I've got my hands on several 20x2 character displays which don't seem to work. This is what they look like: Apparently, they are HD44780-compatible. The three 16-pin connectors (single-row ...
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1answer
269 views

HD44780 DDRAM and CGROM Interaction

I am looking at interfacing to a HD44780 LCD display with an STM32VL discovery board. I am aware drivers exist but in the interest of learning I am doing it myself. I am curious about the interaction ...
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1answer
818 views

How do I get this LCD to work on Proteus? [closed]

I'm trying to display the letter "A" on LM016L (datasheet). I keep switching the E input but I get nothing. This is my circuit:
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2answers
1k views

What is the expected lifespan of those 16x2 character LCD?

I want to use the HD44780 character LCD (commonly available in 16x2 characters, though I am using the 20x4 version) in an industrial application but since it will be on 24x7, I am just a bit worried ...
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1answer
2k views

power HD44780-based LCD with 3.3V by using a negative contrast voltage?

I have a circuit that runs on 3.3V and want to use an HD44780-based LCD with it (which normally requires 5V). The LCD logic and backlight works fine with 3.3V, but the contrast doesn't, so nothing can ...
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1answer
234 views

Will HD44780 display be hurt with 20mA on contrast pin? (pin 3)

I'm driving an LCD HD44780 display using my Raspberry Pi B+. Using a GPIO pin I'm managing the contrast adjustment (pin n. 3) on my LCD display with PWM. In the ...
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1answer
5k views

How to fix Hitachi HD44780 16x2 LCD garbled display in 4 bit mode?

It often happens that a HD44780 16x2 LCD shows garbled characters during usage. Most help on the web advises for using snubbing techniques to prevent voltage noise such as induction spike. I've done ...
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2answers
2k views

LCD interfacing with msp430

I am making a contact less tachometer based on magnets .I am using msp430g2253 micro controller and HD44780 lcd. I have done certain calculations for calculating rpm in the main code and now i want ...
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1answer
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driving a 5v LCD with a 3.3v atmega328p microcontroller

Am using adafruit (American hobbyist electronics components retailer) breakout for the max31850 thermocouple amplifier who's data line isn't 5v tolerant. Therefore I want to power my atmega328P @ ...
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2answers
574 views

HD44780 in 4bit mode connected to only ONE PORT on PIC

i am new to PIC programming. I am using MPLAB X + XC8 compiler. I have on a breadboard an PIC18F4550 connected to a HD44780 compatible LCD. Digging online i found out a routine to interface the PIC ...
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4answers
1k views

Wiring up an LCD display with unknown controller

I found an old LCD in my pile of trunk. I would like to be able to use it. However, someone (possibly / probably me) sawed off the part of the PCB with the series code, so I can't know what the ...
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4answers
2k views

Weird problems with LCD (HD44780 compatible)

I've been trying to interface with a HD44780 compatible display (16x2) for quite a few hours now, but have run into some weird behavior problems which I can't solve. My setup: I'm using the LCD in 4-...
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2answers
4k views

Using HD44780 display without contrast potentiometer

I found tutorial about connecting HD44780 display to Raspberry Pi. In this tutorial there is no contrast potentiometer. Vo is connected to ground. Tutorial author says: In order to control the ...
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2answers
426 views

Extra pins on HD44780 lcd

I am looking at ordering this lcd https://www.sparkfun.com/products/255, however when looking at the picture it seems that there are some extra pins on the right side not described in the hd4470 ...
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2answers
253 views

Does C-1602A-1YN LCD use the HD44780 controller?

I am new to using PIC microcontrollers and electronics in general. I have been reading a tutorial on how to interface a PIC with a HD44780 compliant LCD. As I have been shopping for a LCD I have been ...
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1answer
620 views

16X2 character LCD changes contract intermittently and doesn't work with raspberry pi

I've been following adafruits RPi tutorials (and bought their starter kit) I had an Sparkfun LCD Kit lying around. (It has an HD44780 controller LCD, a 10K trimpot and a 16 pin male header) I ...
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1answer
595 views

A small, thin LCD for my device [closed]

I've been looking for a good display for the handheld device that I'm building and I've liked the various HD44780-based displays that I've tried. (like for example this one: https://www.sparkfun.com/...
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1answer
4k views

How to program an ATmega32 in C++ to control a LCD?

I'm electronics student. I'm a newbie in programming. I have loved C++ after watching some videos on C++. Am using Atmega32 uC, WinAVR GNU GCC compiler programming tool, 16*2 Hitachi HD4478OU LCD for ...
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3answers
902 views

How does the HD44780 LCD work at the low level?

I'm not asking for a driver specifically, but how exactly it works. I looked up the 2 chips that were in it. HD44780A00 and HD66100F to be exact. I'm assuming one is a display driver? And the other ...
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2answers
3k views

Interfacing HD44780 compatible LCD display and Spartan 3 FPGA

I've recently bought HD44780 compatible LCD screen (16x2) from eBay. I want to use it with my Spartan 3 FPGA development board, but after I've thought a little about it, I'm not sure that I can use it....
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1answer
1k views

HD44780: How long do I have to wait for busy flag to reset?

I'm driving a HD44780 controlled character LCD (HY-0802B-104-R) with shift registers (74LS164). So, the communication will be one-way only; I won't be able to read any data from the LCD. Normally, ...
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5answers
3k views

Power-up Initialization of HD44780 LCD Module

I'm using an HD44780 clone LCD module a KS0066U. Everything works ok on the module except when I rapidly power cycle the device (on->off->on). For some reason a very short interruption in the power ...