Pic18F452

[TonyCNC]

Hi iam am trying to use a lcd display using the picbasic pro software the display is working fine using the defult pin setup but when i change the pin configeration using the DEFINES i cant get the display to work.
can anyone help me out thanks.

[Melanie]

That's the equivallent of...

Question : "My car's broke - can you fix it?"

Answer : "Sure, bring it in and we'll take a look".

Inotherwords, post your Defines so we can see them, along with your chip register initialisation... ie if you're using analogue pins your ADCON or CMCON setup, and confirm that if you're using odd hardware pins like PortA.4, you've got a pull-up on it.

[TonyCNC]

Hi Melanie my lcd defines are:
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_DREG PORTD
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTE
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTE
DEFINE LCD_EBIT 1
DEFINE LCD_RWREG PORTE
DEFINE LCD_RWBIT 2

[MikeTamu]

If you look at the datasheet, you can see that PortE, bit 0,1, and 2 are all Analog ports. So what is most likely happening, is that the PIC is in analog mode for these pins and not giving you digital outputs.

Put this in your code before the DEFINES:

ADCON1.3=0
ADCON1.2=1
ADCON1.1=1
ADCON1.0=0

These 4 lines will make all of your analog pins into digital pins. If you need to use some of your digital pins as analog ones, then just change these 4 bits according to the table in the datasheet referenced below.

To see how I came to this, look at page 182 (184 of pdf) in the PIC 18f452 datasheet.

[TonyCNC]

Thank you very much MikeTamu i just assumed that PBP took care of all that for me as there is no reference to it in the pbp manual.

Thanks again.

[charudatt]

I am having similar problems trying to get an LCD working on EasyPIC3 from Mikroelectronika Board using PBP and 18F452 MCU. Although i can get the LED to blink , I cannot get the LCD to work. Can you help.

EasyPIC3 Development Board Configuration -
D4 - RB4
D5 - RB5
D6 - RB6
D7 - RB7
RS - RB2
E - RB3
RW - GND

My Code:

DEFINE OSC 8

' HARDWARE DEFINES
'-----------------------------------------------------------------
' Define LCD pins

DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 2
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 3

'-----------------------------------------------------------------
TRISA = %111111 'INITIALIZE PORT DIRECTIONS
TRISB = %00000000
TRISC = %10101001
TRISD = %00000011
TRISE = %00000111
Adcon1 = 7 ' Set PORTA DIGITAL
INTCON2.7=1 ' DISABLE Pull-Up's
'-----------------------------------------------------------------
PAUSE 500

Lcdout $fe , 1 , "EasyPIC3 DEV"
LCDOut $FE,$C0, "Board v1A"
PAUSE 2000

END

[Lotondo]

If you look at the datasheet, you can see that PortE, bit 0,1, and 2 are all Analog ports. So what is most likely happening, is that the PIC is in analog mode for these pins and not giving you digital outputs.

Put this in your code before the DEFINES:

ADCON1.3=0
ADCON1.2=1
ADCON1.1=1
ADCON1.0=0

These 4 lines will make all of your analog pins into digital pins. If you need to use some of your digital pins as analog ones, then just change these 4 bits according to the table in the datasheet referenced below.

To see how I came to this, look at page 182 (184 of pdf) in the PIC 18f452 datasheet.

Thanks for the clear explanation !
As you said this will turn all 8 pins into digital.
Would it be possible to get AN0 and AN1 digital and all the others (AN2 to AN7) analog ?
It's still unclear in this case what's ADCON0 for !
Thanks for clearing me out.
Lotondo

[mister_e]

Hava a look in the datasheet, register 17-2, PDF page 184

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