PIC Basic Code Understanding

[HenrikOlsson]

1 DEFINE LCD_DREG PORTD
2 DEFINE LCD_DBIT 4
This tells PBP that you have your LCD data-bus connected to PortD and that it "starts" at bit 4 of that port. In other word, the databus is connected to PortD.4-7 which means you are using it in 4-bit mode and that you'll also need:

DEFINE LCD_BITS 4
To tell PBP that you're using it in 4bit mode.

3 DEFINE LCD_RSREG PORTE
4 DEFINE LCD_RSBIT 0
This tells PBP that the RegisterSelect of the LCD is connected to PORTE.0

5 DEFINE LCD_EREG PORTE
6 DEFINE LCD_EBIT 1
This tells PBP that the Enable of the LCD is connected to PORTE.1

If your PIC doesn't have a PORTE then change the DEFINEs so it matches what you have - that's what they are there for.

/Henrik.

[malc-c]

Using the attached image and the following code will better explain Henriks post with regards to using other ports

DEFINE LCD_DREG  PORTB          ' LCD Data port
DEFINE LCD_DBIT  0              ' starting Data bit (0 or 4)
DEFINE LCD_EREG  PORTB          ' LCD Enable port
DEFINE LCD_EBIT  5              '     Enable bit  (on EasyPIC 5 LCD)
DEFINE LCD_RSREG PORTB          ' LCD Register Select port
DEFINE LCD_RSBIT 4              '     Register Select bit   (on EasyPIC 5 LCD)
DEFINE LCD_BITS  4              ' LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2              ' number of lines on LCD
DEFINE LCD_COMMANDUS 2000       ' Command delay time in us 
DEFINE LCD_DATAUS 50            ' Data delay time in us

You can then use the following to initialise the LCD

LCDOUT $FE,1:FLAGS=0:PAUSE 250:LCDOUT $FE,1:PAUSE 250 ' Initialize LCD

[lilimike]

Hi pr2don,

I am just one week late but if you are still learning or trying to understand, this is where I learned how it works.

http://iamsuhasm.wordpress.com/tutsproj/using-lcds/

Mike

[shah_kunjan]

Using the attached image and the following code will better explain Henriks post with regards to using other ports

DEFINE LCD_DREG  PORTB          ' LCD Data port
DEFINE LCD_DBIT  0              ' starting Data bit (0 or 4)
DEFINE LCD_EREG  PORTB          ' LCD Enable port
DEFINE LCD_EBIT  5              '     Enable bit  (on EasyPIC 5 LCD)
DEFINE LCD_RSREG PORTB          ' LCD Register Select port
DEFINE LCD_RSBIT 4              '     Register Select bit   (on EasyPIC 5 LCD)
DEFINE LCD_BITS  4              ' LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2              ' number of lines on LCD
DEFINE LCD_COMMANDUS 2000       ' Command delay time in us 
DEFINE LCD_DATAUS 50            ' Data delay time in us

You can then use the following to initialise the LCD

LCDOUT $FE,1:FLAGS=0:PAUSE 250:LCDOUT $FE,1:PAUSE 250 ' Initialize LCD

Hello Sir,

I am doing same things and working fine but sometimes when i power on the controller LCD doesn't display anything or it may display some garbage characters.

I am using pic 16f876A controller with crystal freq 10Mhz

LCD controller - Samsung KS0066

any suggestions are well comed...

thanks in advance

[malc-c]

Occasionally I've experienced similar things after the initial re-programming. Resetting the PIC or power to my development board always works for me.

[Charles Linquis]

You often have to pause about a half second before you write anything to the LCD. The displays are slow to get "started". The quarter-second pause in the previous example may not be quite enough.