lcd module 1602a qapass datasheet pdf brands

Directory  Summarize  Shape dimension  Module mainly hardware description  The external interface module  Command instructions  Ceading and writing operation sequence  Software initialization...

Summarize （1602A QAPASS ）is an industrial character type LCD, can also shows that 16 x02 namely 32 characters. (16 column 2 line) Second:module size (pictured) Three:pin interface specifications table Numbers symbols pin pin that Numbers symbols that Numbers symbols Pin that...

1 foot: for to power VSS. 2 feet: VDD take 5 V is power. 3 feet: VL for LCD contrast the adjustment, and then when the power is the weakest contrast, grounded contrast the highest, and the contrast Through high can produce the "ghost", when used, can pass...

4. 1602 LCD instructions in time sequence that 1602 LCD module internal controller of article 11 control instruction, as the chart shows: Numb instructions Clear display Cursor to return to Buy input mode Display the on/off control The cursor or character shift Buy function Buy character CunZhuQi...

4: control command table 1602 LCD module of reading and writing, and the screen and light mark operation operations are through the instructions of programming realize. (note: 1 for high Level, 0 for low level) Instruction 1: clear display, instruction code 01 H, the cursor is reset to address 00 H position. Instruction 2: the cursor reset, the cursor to return to address 00 H.

The basic operation sequence table Graph: read operation sequence Graph: write operation sequence 1602 LCD RAM address mapping and standard word stock list. Liquid crystal display module is a slow display device, so in the execution eachinstruction before must affirm module mark is busy low electricity Flat, said were not busy, otherwise this instruction failure.

LCD display for replacing a broken one or for creating something new. This LCD display can be used easily with Arduino, Raspberry Pi, Intel Edison or any other embedded system you want to work with.

Due to the ancient LCD controller technology made by Hitachi, the board controller requires 5VDC operating voltage. In order to easily use this display with say Raspberry Pi (3,3VDC) you need to hack this display a bit. In order to make it work with lower operating voltage, add a 8pin voltage converter such as ICL7660 (or similar) onto the space indicated with label U3. Then populate C1 and C2 with 10µF SMD capacitors and remove J1 solder bridge. To finalize the job enable the voltage converter by soldering a solder bridge across the J3 contact pins. You have now an LCD display capable of operating with lover operating voltage.

#include // includes the LiquidCrystal LibraryLiquidCrystal lcd(1, 2, 4, 5, 6, 7); // Creates an LC object. Parameters: (rs, enable, d4, d5, d6, d7)void setup() {lcd.begin(16,2); // Initializes the interface to the LCD screen, and specifies the dimensions (width and height) of the display }}void loop() {lcd.print("change me"); // change the text to change the textdelay(3000); // 3 seconds delaylcd.setCursor(2,1); // Sets the location at which subsequent text written to the LCD will be displayedlcd.print("change me");// change the text to change the textdelay(3000);lcd.clear(); // Clears the displaylcd.blink(); //Displays the blinking LCD cursordelay(4000);lcd.setCursor(7,1);delay(3000);lcd.noBlink(); // Turns off the blinking LCD cursorlcd.cursor(); // Displays an underscore (line) at the position to which the next character will be writtendelay(4000);lcd.noCursor(); // Hides the LCD cursorlcd.clear(); // Clears the LCD screen}

As far as I know, if all the connections and power busses are correct, and you"re using series protection resisters between the 5V LCD and the 3.3V Propeller pins, then the on power up all "generic" HD44780 LCD"s will be in factory default 8-bit data mode and must be programmed (initialized) by the driver first to work in 4-bit mode. You do not need all eight (db0-db7) LCD pins connected to initialize to 4-bit mode (db4-db7 connected).

I"m using a 5V (only) 4x20 P/N YB2004A HD44780 compatible LCD with blue background and white characters in 4-bit mode. Many have used this particular LCD module with success.

All the LCD data I/O and control lines are connected to the 3.3V Propeller via 4.7K resistors for protection. All my connections to/from the LCD are less than around 3 inches and connected directly to the prop pins on my tried and true home-brew DIP Propeller dev board.

The first time I connected the brand-new out-of-the box LCD and ran the jm_lcd4_ez driver object it worked fine. Just as expected from what I can see in the driver demo object when properly configured for my 4x20 LCD connected to the Prop-I.

The contrast is set properly on my LCD from the first succesful run of the jm_lcd4_ez object. My LCD likes 0.7V on the contrast pin, which from my experience is correct. At the moment I"m setting the contrast from the wiper of a small Bournes PCB mount 10K multi-turn pot with the pot"s end-leads connected between 5V and GND. 5V is connected to the CW rotation wiper end.

Tip: If you don"t want to use a pot to set the contrast, try putting a signal diode like a 1N914/1N4148 diode with cathode to ground in series with a 4.7K or 10K resistor to 5V, then connect the diode cathode to the LCD"s contrast pin. This should set your contrast pretty-much correct without having to use a pot or a fixed divider. But before doing this you may want to verify your LCD contrast is OK with around 0.7V on the contrast pin with a pot first.

With the backlight on the 5V bus is reading about 4.9V, so the backlight isn"t overloading the 5V power bus. The backlight is drawing around 110mA which is as expected for this 4x20 LCD. My 5V bus is regulated via a venerable 7805 regulator fed with 8V.

Next, with the jm_lcd4_ez driver working, and without making any changes to the driver example code, I reloaded the previously working jm_lcd4_ez object code into the Prop RAM.

Any type of power on/off reset and reload of the object doesn"t work. Now the LCD just sits with the top-most line and third line from the top all pixels on and the other two lines blank. I think this may be the correct initial power on display for the 4x20 LCD. I remember with 16x2 HD44780 LCDs that power on reset with no data coming in results typically in the top line being all pixels on and the second line being blank.

As I remember, these generic HD44780 LCD"s don"t have any hardware reset pin. The LCD"s are reset to factory defaults upon power up with no non-volitile storage on the LCD. You have to properly re-initialize the LCD for data-pins used (4 or 8) etc. in software upon first power-up every time. If this is indeed true in my case, then I shouldn"t be seeing this problem unless there is a hardware interconnect problem.

Next I added a three second delay to both of the objects mentioned above right after power up and before the LCD is initialized. This was just to make sure everything settles down before communication with the LCD starts.

1. For a third time, reconnect and recheck the LCD/Prop interconnections. Maybe make the leads shorter or reduce the 4.7K protection resistors to something like 2.2K (in desperation).

The "4-bit Parallel LCD driver" by Chris Gadd in Obex is very well documented, worth a read IMO. Unfortunately for me I"m trying to use a 4x20 LCD, this object is for 16x2 only. I"m not sure if this matters for a simple test though. I may give it a try:

* Recheck all your LCD connections. Keep them short. Try to separate the pins for the control lines to reduce cross-talk (the four data connections typically all need to be contiguous). I do not recommend trying to drive the LCD via a "plug breadboard". Make a direct connection cable with series resistors "mash-up" cable instead. An old floppy drive connector/cable cut down (short) with soldered series 1/4 or 1/8 Watt resistors can be used for this in a pinch. Apply some hot glue to the resistors to keep them in parallel, at least for the four LCD data pins, if you are separating the I/O control pins.

* Be SURE to use series protection resistors between the 5V LCD and the 3.3V Propeller to prevent damaging the Propeller during power-up and LCD initializatoin or LCD read.

* Recheck how you are setting the LCD pins in the driver object. Check the pins with a logic analyzer if you have one (I use the Open Bench Logic Sniffer).

* Try putting a waitcnt delay of several seconds in your LCD demo object before the LCD initialization occurs to allow things to settle down before the LCD driver starts communicating with the LCD. This example will introduce a wait of 3 seconds:

* Try the LCD without the backlight on. Maybe the backlight is overloading your 5V bus. The backlights take a lot of current. If you do use the backlight, make sure the 5V bus voltage is within tolerance.

I apologoze for bothering you again, but figure out that pin numbers are hardwired so we do not need to use them, but you are running it a 4Mhz frequency, I am trying to so it at 8Mhz, in what places should I change the code. Also I used the meter to check ao,a1,a2 and all three report avoltage of 4.9v. this means they are tied high, so my address will be 0x27, correct? I am using PCF8574T. The program is hanging somewhere in lcd_init. Any help will be appreciated.

Well, we have to use a multimeter to match the LCD pins to the PCF8574T pins, on our board they were totally different. After setting the pins correctly in LCDPCF8574.h file, the code worked like a charm

I also get solid block of squares in one line only but I can"t get this even to compile... i keep getting some compile errors about LCD_DISP_ON_BLINK and 2, or 3 other lines.

To be clear i really don"t understand all this stuff what it mean and avr studio is quite strange to me, but even i know that my pin connections are different I could fix that later based on Your previous advice for lcdpcf8574.h.

For now i don"t know how to get compile ok. My mcu is Atmega168 @8MHz internall. I"m trying to get this to work just to know does my pcf8574t chip is still live at all because i"m also trying to controll lcd on such was using some other programming method.

i really don"t know how to do anything of that. Write my own makefile? hah, good one... :) I don"t know even #C at all. That"s why I"m using Flowcode, programming mcu by putting blocks around but there are also some tricky issues about i2c LCD that gives me a headache and matrix multimedia support sucks.

I don"t think that i will need that hex more than one (this) time, simply to check my hardware to know am I doing something wrong in Flowcode or my PCF8574 chip is simply dead for some reason and that"s why I don"t get normal result on LCD. that"s all

Ok. For neebie you should consider working with Arduino, which is really simple! Just import that code in your avr studio project. Keep in mind that you will have to change some registers in order to make this works on mega16. Give it a try to arduino, the LCD i2c library is really simple.

I"m using a 20x4 LCD from YwRobot, which comes with a PCF8574. I have it connected to analog pins 4 (SDA) and 5 (SCL) on an ATmega328P. I have made the following connections, which I believe are correct: DATA0 = 4, DATA1 = 5, DATA2 = 6, DATA3 = 7, RS = 0, RW = 1, EN = 2. The backlight seems to just be connected to Vcc (which pin should I set it to?).

I used this library to run PCF8574T on ATmega16A. I got cheap ebay display with I2C backpack ( PCF8574T) module. I changed pins in .h file and communication works ok (Im able to write something on display), but there is no backlight. The thing is that there is backlight for some ms, but when display init method starts, it turns off backlight somehow and I cant figure out why. Its some kind of invert mode I think.

The setup pin for the lcd light is LCD_LED_PIN (lcdpcf8574.h). The function to light up and down is lcd_led. In normal mode lcd_led(1) will turn the led on, lcd_led(0) off, in inverted mode, it works inverted, so 1 to off, o to on.

now, while i running the pc program for sending data to mcu, my main routine stop to work and in lcd i see only data from pc and not from ultrasonic sensor.

I had a problem with compilation that code . Something like " Poisoned SIG_USART_DATA nad SIG_USART_RECV . So I found and changed that uasrt.h file and uart.c file into almost the same ( now SIG_USART_DATA is UART_UDRE_vect for example ) the rest is same. Compillation is without any problems, but nothing appeared on my LCD :( I have been trying to resolve that problem for 8 hours. I am using pcf8574T and I changed pins :(

I would add that I am using that set http://www.ebay.com/itm/Arduino-IIC-I2C-TWI-162-1602-16X2-Serial-Blue-LCD-Module-Display-Screen-/190573003243 and ATMEGA8 .

Uart is there just for debug purpose. You could also remove that, or use anyother library. What i can say is that on HD44780 based LCD wiring is really important. So double chek it. Also, you could use a logic analyzer to debug the pcl8574 to lcd bus. Check that pcl8574 output works as desider, debug the output editing the code. Compile using avrgcc. Compile using your actual micro F_CPU. Check SCL_CLOCK of the twimaseter.c

Thanks for answer, I will try to remove uart files. Can u only please tell me about configuration of pins for that: http://www.ebay.com/itm/Arduino-IIC-I2C-TWI-162-1602-16X2-Serial-Blue-LCD-Module-Display-Screen-/190573003243

In order to ensure there"s no hardware issue I tested the i2c communication with the LiquidCrystal_I2C library from the Arduino IDE and it all worked fine. I could send text to my LCD display via i2c.

Today I changed the SCL from 100000UL (100 KHz) to 400 KHz and 1.7 MHz, but none of these configurations worked. My F_CPU is at 16 MHz. According to the datasheet of the port expander (pcf8574) it requires an i2c SCL of 100 KHz to work properly, so I made my changes undone and set it back to 100 KHz.

The root cause of problem was that PC4 & PC5 pins were not configured as output and was not set to high initially. Here is the list of changes need to be done on original code to let Arduino Uno and QAPASS LCD with Funduino I2C interface work:

Hello, this libary was built to drive one display at time, anyway, if you want to drive more than one you can do it by changing functions in lcdpcf8574 files. You should built up an array of deviceid, then add the deviceid variable to all the funcitions. This is one way to do what you need, not the only one.

Yes, i understaind it. You have to implement multiple deviceid on the lcdpcf8574 library. This library cant at present drive one display. If you implement an array of multimple device id, you can drive many display at the same time.

Came up with a problem after changing 20x4 blue series lcd screen to a green lcd series screen.Screen sometimes started up perfectly other times just produced garbage. Reliability was restored by adding 20ms delays after the lcd_e_toggle function calls in lcd_write function. This would seem a rather heavy handed solution if the problem is an iniation issue. I"ll keep looking.

The schematic shown must be for a rather old version of the I2C-to-HD44780 character LCDs. All the ones available in 2016 have been updated to have 3 address offset solder pad jumpers. Also, the LED backlight driver circuit has a 2-pin push-on jumper to cut/supply power to the backlight LED.

Do i need just include lcdpcf8574.h to my code or which one? Your source code which has i2cmaster.h, lcdpcf8574.h, pcf8574.h, uart.h makes me confuse.

You have at least to include and compile files in lcdpcf8574, pcf8574 and i2chw. But you can also use another i2c library, if so you can use your and not use the i2chw one. Uart library is there just for debug purpose.

I saw in your software that a UART is initialized. I also see a uart used in the main,c. Do I have to use UART anywhere. I am only interested in the LCD ans pcf8574T use.

I"m developing a system that allows to set a square wave period, then, once setted, it drives a led with a square wave with the setted period. It also uses an I2C LCD for the user interface, that uses your library. Anyway if i set the period, the output square wave isn"t consistent, with heavy random period variation.

Hello MHMLB. You have to add the folders in the compile path. "Ficheiro ou directoria inexistente", your compiler can not find the lcdpcf8574.h file. Take a look here https://www.instructables.com/id/How-to-get-started-with-Eclipse-and-AVR/

Hello Florian. Thank you. The Rear/Write pin put the LCD between Read/Write mode. It"s just because it does not works like this, for further information you can take a look here: https://www.sparkfun.com/datasheets/LCD/HD44780.pdf as example look at "Interfacing to the MPU" figure 9.

Hey Davide, I"ve been using your code on an Atmega 8 with a 20x4 LCD display and it works very well. I was just wondering if there was away to speed it up so text appears instantaneously on the screen rather than scrolling across?

I have problem with LCD 2004A. If I"m printing for example one char in loop it will not print anything on line4. When cursor should move to line4 it will move to line2. I did some debugging but I cant find the root cause of this issue.

You should change the line LCD_DISP_LENGTH to 80 as LCD 20x4 have 80 characters. Also change the line TEXT_WRAPPING (I think, it below few lines from LCD_DISP_LENGTH) and change it to 0.

Hi Davide. so I spent 3 days searching for i2c lib for atmega16A and here I am here. it seems to work with a lot of people here but not with me . I fixed all the errors that appear and it compiled without errors on Atmel studio 7 but nothing on UART or on i2c lcd.. I am using proteus.. plz I am disparate for help

Your library is very nice and works fine. I have one question. I am using atmega328p on aruino board and I want to use on SPI one more device (GY-906 IR temp sensor). Is it somehow possible? I tried use your example, but into while(1) loop I put my working code before lcd_puts() to read temperature from sesor via SPI. But this not works (display is not showing anything) and on first look I think, that lcd needs to be again addressed after reading temperature. Generally, how should it be done correctly? I mean communicate with lcd and another SPI device/s with your library.

Hello, yes it"s possible. You can use two SPI. At first, you should initialize SPI once. Then, I would check the GY-906 reading using something like the UART. Then I would check the lcd usage. Then, only after both works, I will put all togheter.

Thanks for your reply. Yes, this is exactly what i did. GY-906 with SPI works in my test project. LCD also works in test project. Now I am connecting both these parts. In my main loop i have code as shown bellow. When I comment part beggining with "i2c_start(GY905ADDR+I2C_WRITE);" and ending with "i2c_stop();", then LCD is working and writing some text from code bellow this section. But when I remove comment, display is not showing anythink. It must stuck somewhere on SPI GY-906 sesor section I uncommented. Do you have some idea? I can provide some way whole project if it can help.

So at the end I solved the problem. Code was stuck on line "i2c_write(0x07);". Problem was, that for testing GY-906 I used Peter Fleury library directly downloaded from his web page with SCL_CLOCK 100000L in twimaster.c file. Your LCD library had difference in this define, SCL_CLOCK 10000L. So I solved this by changing 10000L clock to 100000L clock in your project. Now it works, sensor and LCD, both on SPI bus. I am not sure, why you have like this, but it can be cunfusing for another peoples.

Thank you for your library. It worked great with me (ATmega328P and LCD 20x4 i2c) after I change some define line in your lcdpcf8574.h file. But there is a small problem. My refresh rate is quite slow (I can see the clear progress invidually), although I increased the SCL_CLOCK up to 100000L and 400000L, my F_CPU change to 16Mhz, all defined in the main.c file in the src folder. So I wonder that maybe I can increase my screen refresh rate somehow?

Hello, thank you. You should try editing the lcd_write function, although I haven"t noticed that slow speed, indeed I"ve to slow the display loop down if I do not want the screen to "flicker".

Looks like I found a bug in lcdpcf8574, the mode "LCD_WRAP_LINES" doesn"t make sense for 20x4 display. Please take a look addressing of the typical LCD 20x4:

So it makes a mess, if you use position (0,2) it happens in (0,1) instead and if you use (0,3) it happens in (0,2) place instead. Because in 20x4 LCD address space is split between odd and even lines.

Hello, thank you for your post. I don"t have a 20x4 now. I"ve to think about this, first of all, have you changed the LCD_DISP_LENGTH macro from 16 to 20?

As i said I do not have a 20x4 right now. You can disable this mode just setting LCD_WRAP_LINES to 0. Anyway if it happens to me to have a 20x4 or you find a way to solve this please share this. Also consider that this library is based on the P.Fleury one (http://www.peterfleury.epizy.com/avr-software.html), there are a few post on avr-freaks about this library, I"ven"t find this kind of error there. But if you find this, please tell me.

This is slightly difficult guide for the beginners as it involves soldering and wiring is complex. Here is detailed steps on how to for 1602A LCD display Arduino connection. In this guide we will also talk about the soldering part. The units do not cost more than 3 USD per unit but there is no in-built pins – usually male header pins supplied. We talked about different types of wires in electronics. We can use solid core wires instead of male header pins and solder. Arduino has the needed Library included :

With the above connection, again connect your Arduino with computer, the LCD will light up. Adjust the potentiometer and you’ll be able to see from blank to white all units like [] [] [] []. That [] [] [] [] is full contrast and blank is minimum contrast.