Do I need that Resistor with my LCD?

Do I need that Resistor with my LCD?
See also thread - Pin RA4 doesn’t work


If you look at the hardware connection examples of the LCD to a PIC in the PIC Basic manuals, you will see a pull-up Resistor connected to RA4. Only if you use this pin then you need a pull-up Resistor because RA4 is an 'open-drain' type connection for Output.

If you use a different pin for connecting (the RS pin in the MeLabs example) to the LCD, then this Resistor is not required. Don't forget to change the appropriate LCD define...

Example. To use RB2 instead of RA4 and dispose of that extra Resistor, add into your code...

Code:

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DEFINE LCD_RSREG PORTB        ' Set Register Select PORT
DEFINE LCD_RSBIT 2        ' Set Register Select BIT

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These DEFINEs are placed at the top of your program and must be in UPPERCASE (although the word Define itself need not be uppercase). See also thread – Watch the SPELLING of your DEFINEs.