I have a Keil C code for using 16x2 LCD in 4-bit mode. the code is working fine.........
Problem: If "RS", "E" control pins (on LCD) are on a different port than the Data port, the code works fine....... But if the Data and Control Pins are on the Same Port, there's nothing appearing on the LCD.
please suggest any reason (and remedy if possible) for this.........
Controller: P89V51RD2 80c51 core 8-bit CPU with 64KB Flash, 1Kb RAM from NXP(Philips). LCD Module: Hitachi HD44780 controller based 16x2 Alphanumeric Green Backlit LCD.
Your code does not take care to avoid disturbing other bits when writing to the port and/or does not take care to disregard bits that it should.
Have you looked with an oscilloscope?
"and remedy if possible"
Fix the bug(s)!