arduino lcd panel kullan谋m谋 quotation

I put it to clear a certain part of the lcd where the millisecond counter is. It never cleared. When i replaced the lcd.print(""); with lcd.print("."); it displayed an period where I wanted the nothing.

When you pass double quoted arguments to print they are processed as strings. This requires a loop (for every character in string until zero) which in turn will call the write method for every single character within the quoted string. Calling print with a string argument adds the overhead of executing the loop, additional storage for the zero terminated string, a function call with a 16 bit reference argument and the additional function call to write within the print string method. Also write is implemented within the lcd driver whereas the print methods are in a class by themselves (adding a layer of indirection).

This stems from the fact that the LCD controller itself does not inherently support the function and in fact treats the ASCII codes for and as displayable characters instead of control codes.

In my opinion the basic LiquidCrystal library should concentrate on implementing all of the capabilities of the LCD controller and no more. If people want a library that more closely emulates a CRT (or LCD) terminal that is fine, but I think it should be done in a different library.

OK, this is the sketch that I used to try out user-defined characters on a four-row, 20 character LCD. If you have a two-row LCD, you"ll have to change the calls to "drawbar" in the main loop. You"ll need a potentiometer with the track connected to 0V and 5V, and the wiper connected to analog in 0. Turn (or slide) the pot to see the bar extend across the LCD. The crucial command to the LCD is 0x40, which is used to position the "cursor" in the CGRAM, which is where the user-defined characters are stored. A call to "home" is required after defining the characters, to put the cursor back into the main display memory. All this is documented in the HD44780 data sheet.