The print() function is used to write textual data to the DDRAM of the character LCD. These methods are useful in scrolling text across an LCD display: The LiquidCrystal library of Arduino has a number of functions that can be used to scroll text on a character LCD. If you’re not adding any padding between the repeated text scroll, the text segment “5” needs to be scrolled 21 times (the length of the segment), or at least five times (21-16) as per choice.
ARDUINO LCD LIBRARY SCROLL PLUS
These characters are scrolled on a 16-character line while the last text segment should be scrolled however many times is the length of the segment in characters - plus additional padding (spaces) between each repetition of the scroll. The text segments from 1 to 4 have to be scrolled 24 (40-16) times as 40 characters are written to the DDRAM at a time. This is because each line displays 16 characters at a time while scrolling one character at a time. To display and scroll the above-given text string of 120 characters on a 16×2 LCD, it’s necessary to break it into five text segments of 40-character lengths (except for the last one) - with 15 (16-1) characters repeating in each consecutive segment. This means the above string must be broken into following strings to scroll across a line of 16×2 LCD:ġ: “Quick brown fox jumps over the lazy dog ”Ģ: “r the lazy dog Quick brown fox jumps ove”ģ: “n fox jumps over the lazy dog Quick brow”Ĥ: ” dog Quick brown fox jumps over the lazy”
Since only 40 characters can be written to the DDRAM at one time, 15 characters must be repeated from the previous text segment to maintain the continuity of text on a 16×2 LCD. So, let’s suppose the following text string has to be scrolled on a line of character LCD: “Quick brown fox jumps over the lazy dog Quick brown fox jumps over the lazy dog Quick brown fox jumps over the lazy dog “ The size of the text segment that can be written to the DDRAM at a time depends on the number of characters per line that can be stored in the DDRAM of that LCD module. For other LCD modules, one less the number of characters per line needs to be repeated in the text segments. To maintain the continuity of text scrolling across the LCD, some characters from the previous text segment need to be repeated in the next text segment that’s written to the DDRAM.įor example, on a 16×2 character LCD, if the text is scrolled one character per step, 15 characters from the current text segment will need to be repeated in the next text segment that’s written to the DDRAM. If only 40 characters per line can be written to an LCD module at one time, then only 16 characters can be displayed on the LCD at a time. If you want to display and scroll text greater than 40 characters on a line of 16×2 LCD, the only way to do so is to break the original string into parts and write those parts of the text string to the DDRAM one by one, scrolling each part of the text string.Īnother concern is maintaining continuity of the text that’s scrolling through the LCD.
This means any attempt to store a text string greater than 40 characters will override the other line. In a two-line mode, the DDRAM can only store 40 characters per line. For example, the display data RAM (DDRAM) of a 16×2 character LCD can store only 80 characters. The reason for this is that the display data RAM of character LCD modules is limited. In this tutorial, we will flash a long string of text on a character LCD from Arduino and review the different steps and concerns that should be considered.ĭisplaying long strings of text on a character LCD is far from straight forward. However, this requires a careful design of the embedded program. A character LCD module has a small amount of RAM that can store text and supports the continuity of text scrolling across an LCD display. In this tutorial, we will learn about scrolling long string of text on a character LCD, which can be tricky.
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