PIC Basic Code Understanding

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- 1st March 2010, 09:17
pr2don

PIC Basic Code Understanding

I am Learning Pic Basic, and I took ADC Sample code from melabs. I woul like to understand the following LCD Defination

Define LCD registers and bits
Define LCD_DREG PORTD
Define LCD_DBIT 4
Define LCD_RSREG PORTE
Define LCD_RSBIT 0
Define LCD_EREG PORTE
Define LCD_EBIT 1

Lastly

adval.highbyte = ADRESH ' Move HIGH byte of result to adval
adval.lowbyte = ADRESL ' Move LOW byte of result to adval

Will be thank full if Someone Helps me
- 1st March 2010, 09:36
aratti

Code:

Define LCD registers and bits Define LCD_DREG PORTD Define LCD_DBIT 4 Define LCD_RSREG PORTE Define LCD_RSBIT 0 Define LCD_EREG PORTE Define LCD_EBIT 1

Here you define the pin port that you will use to drive your LCD display.

Code:

adval.highbyte = ADRESH ' Move HIGH byte of result to adval adval.lowbyte = ADRESL ' Move LOW byte of result to adval

adval is a word variable (16 bits) and you load this variable in two steps copying two single bytes (adval.highbyte = ADRESH will transfer the high byte) and ( adval.lowbyte = ADRESL will transfer the low byte)

Al.
- 1st March 2010, 10:03
pr2don

LCD config prob

Define LCD registers and bits

1 Define LCD_DREG PORTD
2 Define LCD_DBIT 4
3 Define LCD_RSREG PORTE
4 Define LCD_RSBIT 0
5 Define LCD_EREG PORTE
6 Define LCD_EBIT 1

-Correct me if I am wrong, I understand Line 1 & 2
Line one means the LCD shold read from port D, Line 2 mean 4 bits
Should be connected LCD i.e RD0, RD1, RD2 & RD3
What I dont understand is line 3, 4, 5, 6. I am using pic16f876 & doest not hv pot D & E thats why I want to adapt this code

Thanks
- 1st March 2010, 12:01
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.
- 1st March 2010, 20:17
malc-c

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

http://micro-heli.co.uk/lcd.jpg

Code:

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

Code:

LCDOUT $FE,1:FLAGS=0:PAUSE 250:LCDOUT $FE,1:PAUSE 250 ' Initialize LCD
- 10th March 2010, 00:55
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
- 20th March 2010, 02:58
shah_kunjan

LCD initialization problem

Quote:

Originally Posted by malc-c

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

http://micro-heli.co.uk/lcd.jpg

Code:

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

Code:

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
- 20th March 2010, 11:38
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.
- 20th March 2010, 14:40
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.
- 31st May 2010, 10:38
shah_kunjan

Serial Interrupt Problem

Hello everyone,

I m using Picbasic language.

My problem is: I m sending serially data 2 times from PC and get only 1 time on PIC16Fxx controller.

I have tried polling method, then i have tried "ON INTERRUPT GOTO label"..... But in both methods i got same problem.

Actually my code lenth is very long. ... Is it creating a problem?
Pls giv me solution if anybody find out. I cannot optimize code length....

Thanks in advance

with regards
Kunjan Shah
- 31st May 2010, 11:21
mackrackit

shah_kunjan,
Please post your code. We would be guessing without it.
- 5th June 2010, 05:14
shah_kunjan

Re:

Hello Sir,

My code is too long of about 3000 lines......

It is not possible to post it here. if u give me ur email id then i can mail u....

Thank u

Kunjan
- 5th June 2010, 10:51
malc-c

try attaching the files

Quote:

Originally Posted by shah_kunjan

Hello Sir,

My code is too long of about 3000 lines......

It is not possible to post it here.

Thank u

Kunjan

if you can't attach the file by renaming it as .txt then use winzip or winrar to compress the files and then attach the zip/rar file to a post
- 8th June 2010, 10:33
shah_kunjan

Re: Code for Serial Interrupt

Quote:

Originally Posted by malc-c

if you can't attach the file by renaming it as .txt then use winzip or winrar to compress the files and then attach the zip/rar file to a post

Hello Sir,
i m sending u my code. I m using RS-485 bus network. I m using serial interrupt for 16f876A.
I m sending serially data 2 times from PC and get only 1 time on PIC16Fxx controller.

code:

DEFINE HSER_CLROERR 1
goto Main

DEFINE INTHAND myint

asm
; Save W, STATUS and PCLATH registers
myint
movwf wsave
swapf STATUS, W
clrf STATUS
movwf ssave
movf PCLATH, W
movwf psave

; Insert interrupt code here
; Save and restore FSR if used
bsf _LED ; Turn on LED (for example)
GOTO _Serial

; Restore PCLATH, STATUS and W registers
movf psave, W
movwf PCLATH
swapf ssave, W
movwf STATUS
swapf wsave, F
swapf wsave, W
retfie
endasm

'''''''''''''''''''''''''''''''''''''''''''''''''' ''''''''''''''''''''''''''''''''
Main:
LOW LED
INTCON.6 = 1
INTCON.7 = 1
hserout [dec x," ", dec y]
lcdout $FE,1,#x," ",#y
here: goto here

Serial:
hserin [dec x,dec y]

' x = RCREG
' y = RCREG

low led
goto Main
'Resume
- 8th June 2010, 15:33
mackrackit

Code:

hserin [dec x,WAIT(" "),dec y]

Maybe???