The lcd lights up but it does not display any blocks or text
So what? You want help? The project works as expected? You posted the problematic code in code tags? You posted an image of your project?
the lcd text is displayed for 1602 lcd but the backlight does not light. If i connect R/W to 5V rail the backlight lights up but the text shows random symbols
@the_fastest_walnut, please do not cross-post.
Normally the LCD backlight is completely separate from the display logic. The backlight only uses the last two pins on the display connector. One is the backlight LED anode, the other is the cathode. To light the LED, you ground the cathode, and connect the anode to +5V with a resistor. Depending on the exact model of display you have, and the brightness you want, that resistor could be anywhere from zero ohms to several hundred ohms. Without more details about how things are connected in your circuit, and the exact model of display, I can't give you much more in the way of detail.
Connecting the R/W line to +5V will NEVER get the display to work. That line tells the display which direction the data transfer is to go. By tying it to +5V, you are telling the display that the Arduino is reading from the display, so the display will not accept any data from the Arduino. The R/W line can be tied to ground if you will never be reading back from the display, or else tied to an Arduino pin so you can both read from and write to the display.
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