arduino lcd displays garbage quotation

Hi, i have and LCD 16x2 connected to my Leonardo. I works properly with all the examples son the connection is ok. But I add the LCD to another sketch and it"s just showing garbage, and i have no idea why. I just want to show "Writing:" in the first row, and the variable nombrearchivo in the second row. All of this works using serial, so my only problem is the LCD.

In 4 bit mode, the host and the LCD must remain in nibble sync. If they lose nibble sync with each other, it will never recover so the LCD will start to see garbage commands.

So if the library is in 4 bit mode and you power cycle only the LCD, the host (arduino) and the LCD will not be in the same mode (LCD in 8 bit mode, host in 4 bit mode) and the LCD will see garbage commands.

In 8 bit mode, it is still possible to get glitches on the display, but since things are done byte at a time there is no nibble synchronization issue so any effects of noise should be short lived and future commands to the LCD should continue to work.

The lcd.clear function is slow and can lead to screen flicker especially if done every time through loop(). Overwrite old data with spaces, reset the cursor position and print the new data and only update the screen when the data changes will help prevent flicker.

I"m tearing my hair out trying to get my project to work. I have an Arduino Uno R3 clone (Freetronics 100% compatible) with a 20x4 I2C LCD from DX (part number GY-LCD-V1). I also have four pushbuttons connected via the analog pins (in digital mode.) Other than that I have nothing connected to the arduino other than power via USB to my Mac.

My problem is that the screen freezes or starts showing garbage after a couple of minutes of the sketch running. Sometimes it seems that the screen gets half way through redrawing then just stops (in which case nothing updates the screen until I disconnect/reconnect the power) or starts drawing garbage to the screen, which also takes a cold boot to fix. Either way, the sketch continues running, i.e. the buttons produce output via the serial monitor and the heartbeat LED on pin 13 continues flashing (the main loop flashes it every second). Occasionally the sketch crashes, i.e. no response to button pushes and the LED stops flashing. If I reset the unit (either via the reset button or by closing/reopening the serial monitor) the screen sometimes won"t re-initialise, i.e. the last drawn screen remains and won"t redraw until the power is cycled.

Initially I thought this might be a memory problem. The sketch is big (about 28KB compiled without debug/info defines) and very nearly 32Kb with them compiled in. Free RAM is about 800bytes according to the debug statements. I"ve been mounting the hardware (LCD + buttons so far) in an enclosure, and I had a few days of the sketch running flawlessly, but now it"s back to the normal problems.

In the previous tutorial, we discussed scrolling long text strings on a character LCD using Arduino. However, it’s also possible to display custom characters on the LCD. These custom characters are user-defined and are stored in Character Generator RAM (CGRAM) of the LCD module.

Custom charactersThe character LCDs support ASCII characters that serve as a standard set of characters. The patterns for the supported characters are already stored in the memory (CGROM) of the LCD module. For printing these standard characters, the controller simply needs to “pass” the associated data register value to the address counter of the LCD.

That data register value is, then, stored in the DDRAM and the address counter is updated (and increased or decreased depending on the direction of the text). When the LCD has to print a character, it reads the value from the DDRAM, compares it with CGROM, and prints the character by generating the stored pattern for that character.

Sometimes it’s necessary to print user-defined characters/icons on an LCD. For example, you may be using an LCD module in a communication device and need to print a custom character showing the status of the connectivity. A character LCD may be embedded in a battery-operated device and it may be necessary to display the level of charging by using a custom icon.

The LCD modules, apart from DDRAM, have the CGRAM to store user-defined characters. To generate a custom character/icon, it’s necessary for the controller needs to pass the entire character pattern to the LCD module. This character pattern is stored in the CGRAM of the LCD. A 16×2 LCD module typically has enough CGRAM to store a pattern for 8 characters/icons.

The pattern for custom characters is defined as a group of 7, 8, or 10 bytes, depending on the number of rows of pixels for each character on the LCD. Each byte represents a row of pixels that form the character. The bits of the byte represents the status of the pixels (i.e. whether the respective pixels will turn on or off).

For example, on a 16×2 LCD, each character is printed as 5×8 dots. Therefore, 8 bytes (for 8 rows of pixels) are used to represent a character and 5 LSBs of each byte are used to turn on or off the pixels.

CGRAMMost of the character LCD modules use an HD4478 controller. There can be a different LCD controller on an LCD module. To know what controller is used in an LCD module, simply refer to its data sheet.

Depending on the size of the character LCDs, they have different DDRAM and CGRAM. For example, a 16×2 LCD has 80 bytes of DDRAM and 64 bytes of CGRAM. As there are 8 rows of pixels for each character, the pattern for 8 characters of 5×8 dots can be stored on the CGRAM.

The CGRAM addresses start from 0x40. The first character is stored from address 0x40 to 0x47. This custom character can be printed at the current cursor position by sending the command ‘0’ to the LCD module. The second custom character is stored from the address 0x48 to 0x4F. It can be printed at the current cursor position by sending the command 1 to the LCD module.

Generating custom charactersIt’s fairly easy to create a custom character. Simply determine the pixel map of the character and, then, determine the bytes that should be written to the CGRAM to generate that character/icon. For a 16×2 LCD, which has 5×8 dots characters, the top three MSB for each byte can be ignored. The top three MSBs can be set to 0 in each byte while other bits can be set to 0 or 1, according to the pixels that should turn off or on.

Generating custom charactersTo create custom characters, typically the LCD command must first be set and the CGRAM address needs to be passed. Next, the LCD command to write data to the CGRAM needs to be passed.

When using Arduino, it’s even simpler to create a custom character/icon. The LiquidCrystal library on the Arduino platform has a function createChar() that creates custom characters and icons on an LCD. This function takes the position of the custom character and an array of bytes as an argument. The generated custom character can be flashed on an LCD at the current cursor position by using the write() or print() function.

The createChar() mskethodThe createChar() function creates a custom character/icon for use on an LCD. Essentially, it writes a user-defined character pattern (a pixel map of the character) to a given CGRAM address.

The position of the character is specified as a number. For example, in the case of 16×2 LCD, 8 custom characters can be defined and their position can be 0 to 7.

The write() methodThe write() function writes a character on an LCD. The character is written (displayed) at the current cursor position and the cursor is moved right or left according to the direction of text on LCD.

If the data passed is a string (quoted in double or single quotes) of ASCII characters, it is written as such. If it’s a number, the character corresponding to that position in the CGRAM is written on the LCD.

The print() methodThe print() method is used to print text to an LCD. If a custom character has to be written on the LCD using the print() method, then the char() function (with the position of the custom character as the argument), must be passed as the argument of the print() function.

Components required1. Arduino UNO x12. A 16×2 character LCD x13. A 10K Pot x14. A 330-Ohms Resistor or any low-value resistor x15. Breadboard x16. Male-to-Male Jumper Wires or Connecting Wires

Circuit connectionsThe LCD module used in this project is JHD162A. This is a 16×2 LCD module with 5×8 character dots. The LCD module has a 16-pin interface. The LCD is interfaced withArduinoin a 4-bit mode.

The LCD module is connected with Arduino in 4-bit mode. The LCD is first initialized and the display is cleared to get rid of any garbage values in the DDRAM.

The patterns for 16 different custom characters are then generated by defining their pixel maps as arrays. Eight of these custom characters can be displayed on the LCD at one time. This is because 64 bytes of the CGRAM of the 16×2 LCD can store a pattern for only 8 characters at any time.

The 8 custom characters are generated by defining their character maps. The cursor position on the LCD is set from column 0 of line 0 to column 7 of line 0, and each character is displayed one by one. Then, the next 8 custom characters are generated and they’re displayed on line 0 of the LCD at the cursor positions from columns 0 to 7.

In the loop() function, the first 8 custom characters are generated using the customChar() method. The cursor position is set by using the setCursor() method. Each character is printed on the LCD by using the print() method at the cursor positions of column 0 to 7 of line 0, one after the other.

After the printing of the 8 characters, a two-second delay is provided using the delay() function. Then, the LCD is cleared by using the clear() method.

Similarly, the next set of 8 custom characters is generated and printed on line 0 of the LCD. It should be noted that we have created and displayed custom characters in the loop() function. So, if the power supply to the LCD module is interrupted for any reason, the custom characters will regenerate and reprint on the LCD.

If we would have generated the custom characters in the setup() function, that code would have only run once. In that case, if the power supply to the LCD module was somehow interrupted, the character pattern for the custom characters would have been lost and garbage values would have displayed on the LCD.

Additionally, we are printing more than 8 custom characters on the LCD even though only 8 custom characters can be generated and printed. This is another reason that we generated the custom characters in the loop() function.

Do it yourselfIn this recipe, you learned to generate custom characters and print them on a 16×2 character LCD. Now think of other possible custom characters and icons, draw their pixel maps (in 5×8 dots), and determine the bytes that should be written to the CGRAM to generate them.

You can modify the above Arduino sketch to print custom characters and icons. You can also try generating character patterns for your regional language or types of common icons — such as a battery status, Wi-Fi, smiley, or other glyphs. Do so until you are limited by the 5×8 dots matrix!

Hello, guys! I am new to Arduino and I am trying to make digital thermometer. Everything works, but problem appears with Lcd screen. I searched through various topics on forums, but none of them seem to solve my problem.

Organic waste becomes a global issue that is still a problem, especially in developing countries. Waste management practices are not uniform among countries (developed and developing nations); regions (urban and rural areas), and residential and industrial sectors can all take different approaches. By using this system, we can crush the organics waste then let it sit for the composting process. In this system, we use the Arduino mega 2560 for processing, we use the 3900 rpm motor and several sensors like temperature sensor, humidity sensor, ultrasonic sensor, and LDR sensor. The automatic mode will make the chopper works efficiently, it will only activate whenever organic garbage put in the chopper. The Manual way will give a mitigation plan for the user. The system equipped with an LCD screen and will give monitoring capability so that the user can monitor the temperature, humidity, waste crushing process, and chopper condition. From the experiment, we see that the average time for the transformation about 6-7 days, as the garbage transforms from the solid pulp into the liquid form with the 27-28 degrees Celcius of temperature. By combining the technology, we can reduce garbage pollution by utilizing the chopper machine and monitored them.

Bought this from Robotshop retailer. Worked right away like a charm. I even changed splash screen to display my software version. However at some point it stopped displaying text, then backlight started spontaneously switching off several seconds after powering on. I connected LCD to different device and started experimenting just sending one command at a time.

My only complaint with this product is the difficulty in mounting. Finally had to drill out the holes to accept 4-40 standoffs. The Eagle files don"t include the complete board so making a screw hole template from the PCB is impossible. Otherwise works fine with my stand alone Atmega 328P using the SerLCD.h and SoftwareSerial.h libraries.

Does anybody know how to do a hard reset on this LCD? While I was uploading my code, I left it plugged into TX, and it doesn"t work anymore. I"m realizing that it probably got spammed with commands and the configuration got messed up. Does anybody know how to reset to factory defaults?

I have the same question. I now have the 3.3v serial enabled LCD (with backpack) and want to use this one for future usage. VDD of 5V can be supplied, but will the TTL work when its getting 3.3V signals from the TX from Netduino?

I"ve put together some python code for sending serial data to these LCD screens. In particular, the code pulls my twitter status and writes it to the LCD. To work with the extra characters, I wrote functions to page the text (vertical scroll) or scroll the text (horizontal scroll). Details are available here: http://dawes.wordpress.com/2009/12/23/twitter-to-lcd/

I spent more time today trying to use this to help in debugging an Arduino, than if I would have just soldered on a JTAG connector, installed linux, and used that.

Is it possible to wire this up in parrellel rather than use the serial function? I ran into a snag and am unable to use the serial function of this lcd? I see the pinouts on the schematic but when wired it doesn"t seem to work.

I"ve created a new splash screen for the Serial LCD, now I want to save it to the Serial LCD memory. So, exactly how do I write a "control-j" to the Serial LCD. I"ve put in the required line to transmit special character 124, but I can figure out how to format the "control-j" line of code. I"ve Googled this for about an hour and can"t find an explanation or sample code anywhere. Here"s my code...void setup() {

I"m not sure if you"re referring to comments on the website, or on your LCD screen. You can contact techsupport@ and they"ll be able to assist you further.

I have used a Labview program for this LCD. When i send character "a", the display is "0". Does anyone having a same problem. How should I troubleshoot this problem.Tq

Has anyone managed to get the PWM backlighting working with an Arduino? I"m trying variations of this and nothing works except the standard On/Off commands using 0xFE as the escape. All my attempts turn the display off but the backlight LED is on full.

Why do I get power out of the VDD port with only RX and GND hooked up? I have a 5V rail that I use to power everything on my board - and when I added this SerLCD I now have a bridge between the arduino power and my 5v line ... which I dont want. Can I add a diode to the VDD to stop reverse voltage from powering my board?

It seems like the MCLR function has been disabled through the config bits. No pullup to Vdd is installed. This makes it really irritating to work with this display. Programming an arduino with this hooked the HW serial port will screw up the display, and without the reset line you have to pull power. A simple solution would just be to wire the PICs MCLR pin to the Arduinos reset line, but this isn"t possible without the MCLR function obviously.

I"m using usb->rs232 adapter for data and an open wire usb cable for power and am getting garbage on all baud rates using code and putty. Am I doing something wrong?

Quick suggestion... It"d be very helpful for some people if you guys added a note in the description pointing people to the correct 3-pin JST jumper wire to be used with these serial LCDs. Two reasons... it"s not clear that the jumper is not included, and you have 3-pin jumpers in your catalog which don"t work with this serial LCD.

I have ported LiquidCrystal library for use with the serial LCD you can look at my code here. Still working on finishing all the documentation. But putting up for now hopefully someone will find it usefull.

I"m also having the same problem after accidentally sending the control character "|" followed by "\", "-", "/" to the LCD as I was trying to animate a rotating bar to indicate a busy status.

The baud rate problem can be solved by writing at 9600, at startup, a "change baud rate" command to the target rate. At worst, the display is already at the target rate and will misinterpret the command and display garbage, at best, it will be set to the right baud rate.

Having ordered this exact LCD myself, I can say that aside from the issue mentioned in my other comment, it looks exactly like the picture. No bulky backpack module, everything is on a single board. Pretty sleek, really.

I used a few of these in my IRcombat laser tag game with my arduino duemiloves and love them. I also used the Red and Black. I like the white and black better outdoors and the red/black indoors. I just wish I could figure out how to send the reset code to them. I know how to clear and change brightness in code, but the ctrl+ command boggles my mind. A few of them have to be unplugged and plugged back in to work after power on because of this issue. Not worth replacing them yet.

Hi...noob question. how do i send data on the fly via arduino? it only has 1 connection to tx. i tried using the serial monitor to send something, but it doesnt work...im looking for something which i guess is similar to liquidCrystal->SerialDisplay example.

I received mine just yesterday and hooked it up. It definitely works, but it occasionally "wigs out" in various ways. I set my own splash screen, which worked fine the first couple of times. The third time I powered it on I got a screen with one line of white blocks and one blank line. It has lost the baud rate setting on me several times. Sometimes I get reverse video garbage characters for some reason.

Edit: Got mine fixed. If you checked the soldering on all the terminals, check them again. I also sometimes was getting strings of garbage if I wriggled the terminals on the LCD (I suspect because I was getting a partial connection on the bad terminal). Resoldered and it is working fine now.

Wait, so I get the 3 pins for power and control, but whats with all the other pins on the sides? Can it be used to control another LCD besides the one built in?

The other pins are used if you want to control the LCD without using the serial standard. There"s some tutorials on how to do that with the arduino below. You have more control over what you can do with it, but it takes up more pins on the arduino. If you want to wire it up this way, don"t spend the money on the serial interface, they have cheaper LCD"s that allow you to do it this way, without the serial.

Seven segment displays are used in common household appliances like microwave ovens, washing machines, and air conditioners. They’re a simple and effective way to display numerical information like sensor readings, time, or quantities. In this tutorial, we’ll see how to set up and program single digit and multi-digit seven segment displays on an Arduino.

Seven segment displays come in a wide variety of sizes and colors. Red, blue, and green are the easiest colors to find. Sizes range from small 0.56 inch displays up to large 4 inch and even 6.5 inch displays. Some displays have a single digit, and others have two or four.

Seven segment displays consist of 7 LEDs, called segments, arranged in the shape of an “8”. Most 7-segment displays actually have 8 segments, with a dot on the right side of the digit that serves as a decimal point. Each segment is named with a letter A to G, and DP for the decimal point:

In common cathode displays, all of the cathodes are connected to ground and individual segments are turned on and off by switching power to the anodes:

Single digit seven segment displays typically have 10 pins. Two pins connect to ground, and the other 8 connect to each of the segments. Here is a pin diagram of the popular 5161AS common cathode display:

Before you can connect your display to the Arduino, you need to know if it’s common anode or common cathode, and which pins connect to each segment. This information should be in the datasheet, but if you can’t find the datasheet or you don’t know your display’s part number, I’ll show you how to figure this out below…

Once you have the pin layout figured out, connecting the display to an Arduino is pretty easy. This diagram shows how to connect a single digit 5161AS display (notice the 1K ohm current limiting resistor connected in series with the common pins):

We’ll use a library called SevSeg to control the display. The SevSeg library works with single digit and multi-digit seven segment displays. You can download the library’s ZIP file from GitHub or download it here:

In this program, we create a sevseg object on line 2. To use additional displays, you can create another object and call the relevant functions for that object. The display is initialized with the sevseg.begin() function on line 11. The other functions are explained below:

byte digitPins[] = {} –Creates an array that defines the ground pins when using a 4 digit or multi-digit display. Leave it empty if you have a single digit display. For example, if you have a 4 digit display and want to use Arduino pins 10, 11, 12, and 13 as the digit ground pins, you would use this: byte digitPins[] = {10, 11, 12, 13}. See the 4 digit display example below for more info.

byte segmentPins[] = {6, 5, 2, 3, 4, 7, 8, 9} –This declares an array that defines which Arduino pins are connected to each segment of the display. The order is alphabetical (A, B, C, D, E, F, G, DP where DP is the decimal point). So in this case, Arduino pin 6 connects to segment A, pin 5 connects to segment B, pin 2 connects to segment C, and so on.

resistorsOnSegments = true– This needs to be set to true if your current limiting resistors are in series with the segment pins. If the resistors are in series with the digit pins, set this to false. Set this to true when using multi-digit displays.

This example consists of a push button and a single 7 segment display. Every time the push button is pressed and held, the display loops through numbers 0-9 rapidly. Once the button is released, the display continues to loop for a period of time almost equal to the time the button was pressed, and then displays a number along with the decimal point to indicate the new number.

So far we have only worked with single digit 7-segment displays. To display information such as the time or temperature, you will want to use a 2 or 4 digit display, or connect multiple single digit displays side by side.

In multi-digit displays, one segment pin (A, B, C, D, E, F, G, and DP) controls the same segment on all of the digits. Multi-digit displays also have separate common pins for each digit – these are the digit pins. You can turn a digit on or off by switching the digit pin.

Since multi-digit displays use digit pins, we also need to define which Arduino pins will connect to the digit pins. Using byte digitPins[] = {10, 11, 12, 13} on line 6 sets Arduino pin 10 as the first digit pin, Arduino pin 11 to the second digit pin, and so on.

Hopefully this article should be enough to get you started using seven segment displays. If you want to display readings from other sensors, the example program above can easily be modified to do that. If you have any questions or trouble setting up these circuits, feel free to leave a comment below.

1.) LiquidCrystalFast seems to yield poor results with the 3.6 and 4.0. Are any updates planned, and/or is this more of an issue with the LCD hardware itself being too "slow"?

2.) I have a similar screen with the Adafruit LCD backpack (I2C & SPI) that I am testing with underwhelming results https://learn.adafruit.com/i2c-spi-l...kpack/overview. Is this also a "slow" screen issue? I understand that I am also reducing the number of pins to transmit the data, but shouldn"t I2C and SPI communication be MUCH faster than was getting without the backpack? Are there better libraries out there (as far as speed goes) other than the Adafruit_LiquidCrystal?