Lcd.h Library Download
Lindsay Arvayo
For as far I know I can do these two things.I can either declare the lcd object with extern in lcd.h. Than every file which includes lcd.h has access to the global lcd object. So both in foo.cpp and bar.cpp I get to type
The best way to get to know the library is to read the header file Lcd.h. I have documented all of the functions and the LCD class rather thoroughly in there. Included with the package is also a README file and a few samples.
The DK-TM4C123 uses SSI to configure and send data to the LCD Panel. The parallel interface of LCD is not there and if it needs to be done then you would have to use GPIO bit banging to emulate LCD Parallel Interface which would not require lcd.c/lcd.h but gpio.c/gpio.h that are already there.
I'm unable to test it right now, but you may well have an new and older version of the library which doesn't declare the POSITIVE variable. Check for which libraries you have installed, and maybe even try to update them via the IDE.
Why don't you just use the Nerdkit library? It's a very simple basic library. If you are determined to use AVRStudio, I believe all you have to do is place the library files you want in your project folder and include them instead of the avr-gcc libraries.
When the compiler takes your C-code and turns it into machine language, it needs to know how to call functions that are not defined in your source code but from some external library or object file. When you call "lcd_home()" for example, it need to know there are no arguments to allocate for and that it returns no value (void). So you have to put a statement in the source code file to tell it where to find the format or prototype for "lcd_home()", and that place is in the .h header files. So it looks like AVRStudio is searching for lcd.h in its default location and can't find the prototype for "lcd_home()" because it's not there. You can override that by giving it the absolute (or relative) path to the NerdKit's lcd.h location. BTW the linker also needs to know that location as well, since it will need the lcd.o file to insert the actual function code into your final executable file.
Rick, I copied the Nerdkit library and added it to the AVR directory. I point to those .h files in my code but I get the same result. What I may have to do is rename the AVR library .h files like lcd.h to lcd_avr.h then copy the nerdkit lcd.h to that directory. I then have to deal with the .o files I guess, that's another mistery (or misery). In short, I have done that already.
PCBolt, very informative info. I will do what I mentioned to Rick and hopefully that will work. One question. arent the .o files derived from the .h files once they are compiled from a .c file? In other words, compiling your own header lcd.c makes an lcd.o and lcd.h file. I also noticed the .h file calling other .h files within, I may have to change all of them. I may take a second computer and load the AVR Studio 5 and play with that.
Actually, object files (i.e. lcd.o) are created from source code files (lcd.c). Header files (lcd.h) are not compiled at all. They are created manually and are used to help you use pre-existing code. They might contain function prototypes, pre-defined macros, pin definitions, global variables etc. They also tell the linker to look for the object files (lcd.o) with the same name as the header files (without the .h extention of course). You'll notice in all the Nerdkit projects the source code you create (i.e. led_blink.c) first get compiled into object files (led_blink.o). There is no led_blink.h because you're not creating any functions or variables to be used by any other programs. Since the led_blink.c file does use outside references, it includes a few header files (i.e. avr/io.h for pin definitions). The linker then comes along and takes your object file (which is machine code specific to your program) and links it with any object file or library listed in the include statements. It sees for example "include avr/io.h" and knows to look for "io.o" or "io.lib" in the "avr" directory. So the include files help the compiler with function prototypes and variable definitions, then help the linker find the object files to link with.
Now, if you are filling a value in the Extra Library Search Path field, this will result in setting a -L flag when gcc is called by the makefile - So this entry will result in appending the flag -L/home/pi/wiringPi. So in fact, you are including one library search path (/usr/local/lib) via the -L field directly and another one (/home/pi/wiringPi) via the Extra Library Search Path field. There should be no reason to use such a mixture of styles in the same project because it is simply confusing.
Third thing: Why did you see the need to pass the same library search path as compiler flags as well as linker flags? There is no real need for that. You link to wiringPiDev twice (through -lwiringPiDev as compiler flag as well as linker flag) and you link to wiringPi three times (through -lwiringPi as compiler flag as well as linker flag and as entry in the External libraries to link). No need for that, most likely you are getting no error because gcc simply ignores the redundant entries.
Assuming that you have placed the library files in the libraries folder of your Arduino IDE, you can include the header file in your sketch. If you will use SoftwareSerial as your communication infrastructure, you have to include its header, too. You can download SoftwareSerial library from the official Arduino website.
My library implementation depends on a specific product, but most of them are very similar to this one. When you buy another, you can use this library with a small or no change. Commands are defined in the header file. All you have to do is to compare these commands with yours.
The mikroC PRO for PIC provides a library for communication with Lcds (with HD44780 compliant controllers) through the 4-bit interface. An example of Lcd connections is given on the schematic at the bottom of this page.
Scrolling text on the LCD is specially useful when you want to display messages longer than 16 characters. The library comes with built-in functions that allows you to scroll text. However, many people experience problems with those functions because:
His Sara, Thanks for your reply. Actually I was wondering if I had used the wrong library as I found I got the same error with some other sketches. I will follow up on your suggestion. Thanks very much for taking the time to reply.
Hi.
Sorry for taking so long to get back to you.
Do you get text on any of the boards? Do you get any error on the serial monitor?
Please make sure that you have the display wired properly and you are using the right library.
Regards,
Sara
I already had a library LiquidCrystal_I2C and I wanted to keep it for use with Arduino Nano etc. So I renamed the library referred to above to LiquidCrystal_I2CE. Then in the LiquidCrystal_I2CE folder the same change to the .h and .c filenames. Then in those two files changed _I2C to _I2CE everywhere.
Hi.
Take a look at this: -i2c-communication-arduino-ide/#3 to learn how to define different pins.
The easiest way is to change line 66 of the following library file (see link below) to pass the SDA and SCL pins to the wire.begin() method.
_I2C/blob/master/LiquidCrystal_I2C.cpp