Why is assigning ports in a “chain” a bad idea? Why have “programmed” fuses the bit value 0? What pitfalls exist when writing reentrant code? The Circuit Our first task is to build the circuit. Apart from the 4 or 8 data-lines, an additional two or three signals are required.

Uploader: Faur
Date Added: 24 October 2007
File Size: 46.11 Mb
Operating Systems: Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X
Downloads: 6324
Price: Free* [*Free Regsitration Required]

There are a lot of good libraries to be found on the Net, ranging from very basic to quite advanced with custom characters, bar-graphs etc.

hd Character LCD Displays – Part 2 – Protostack

The value of the potentiometer is not very important, but k seems to work well. Why is assigning ports in a “chain” a bad idea? The easiest way to get this on windows is through the WinAVR -package, which bundles avrgcc avr-libc and a range of development tools, including an editor and software for device programming. I will not go into too much detail about how to control these LCD modules, since there are already a lot of pages on this subject.

I especially love the way you lay out your wiring on that prototyping board.

I got a hold of these modules when I worked at Zitech Computerway back. The HDbased displays can be operated in either 4-bit or 8-bit mode.

The corresponding hex-codes for the user-defined characters are as follows: To make things easier we need to abstract away the finer implementation details and focus on the operations the developer needs to perform.


How do I trace an assembler file in avr-gdb? Because we want the ability to remove the LCD module later, we will solder a 16 pin female header to the board. The Circuit Our first task is to build the circuit. We are following almost the same series of steps as the 4 bit example in Part 1. It is very simple, and is only made for 2×16 character displays although different sizes could be used with minor changes to the code.

You may want to use a different port for your application, since the two low bits of PORTD are the ones used for the UART in case your application needs to use serial communication. In other cases I recommend finding some existing code.

Breadboards are invaluable for experimenting with electronic circuits. How do I pass an IO port as a parameter to a function?

Similarly, J4 connects the cathode to pin 16, and J5 to pin 1.

Interfacing a HD44780 Based LCD to an AVR

What is this “clock skew detected” message? However, this means that any timing of the data sent must obey the restrictions worst-case from the LCD datasheet, and especially if the microcontroller uses an RC-oscillator for timing this can be a problem because the timing must be set even slower to work in all cases.

Remember Me Lost your password? Variable definitions Part 3: On top, a few preprocessor glueing tricks are used to establish symbolic access to the hardware port pins the LCD controller is attached to, based on the application’s definitions made in defines.


I have some other modules 4×20 and 2×40 charsbut I have not yet found any use for these, so I havent looked much at the pinout for these modules. JavaScript is disabled on your browser. For the 2×16 char displays I have worked with, the first line has character addresses 0xx8F while the second line has 0xCxCF.

The diagram has a slight error on it. If your module has 14 or 16 pins, it shouldn’t avd too hard to figure out the pinout.

After initialization, an instruction can be sent to the display, in order to move the cursor to a specific position. If you need to connect the module to other pins apart from changing the entire portyou should probably consider using a different library. DB0 are not connected or they can be grounded. The power for the backlight is supplied from the Vcc and Gnd connections. Why does the PC randomly jump around when single-stepping through my program in avr-gdb?