Dedicated LCD Controller question

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- 5th February 2006, 14:50
chuckles

Dedicated LCD Controller question

Hi,

I'm fairly new to PICS and have been working on making my own LCD controller out of a PIC16F84A(I had both the PIC and the 2x16 parallel lcd arleady, and couldn't see spending the $$ on a Serial LCD). I've got my circuit board built, using an 8-bit interface to the LCD. The pic runs at 20MHz.
I am using PBP v2.46, Microcode Studio, and the Melabs USB Programmer
My code for the 16F84A is:

@ DEVICE PIC16F84A, HS_OSC, PWRT_ON, WDT_OFF, PROTECT_OFF

DEFINE OSC 20 ' Set speed to 20MHz
TRISB = %00000000 ' All PORTB pins are outputs

' LCD DEFINES
DEFINE LCD_BITS 8
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4 'PORTB.0 is first data
DEFINE LCD_LINES 2 'Number of lines on LCD to be used
define LCD_RSREG PORTA 'Port used for LCD RS Pin
define LCD_RSBIT 3 'Port Pin used for LCD
define LCD_EREG PORTA 'Port used for LCD E pin
define LCD_EBIT 4 'Port Pin used for LCD E Pin
define LCD_COMMANDUS 2000 'Delay between sending lcd commands
define LCD_DATAUS 50 'Delay time between data sent

SerData VAR word
SerPin VAR PORTA.2
TRISA.2=1

pause 1000
LCDOut $FE, 1 'Clear LCD
pause 20
lcdout $FE, 2 'Return to home position
pause 20

GOTO Start

Start:
SERIN SerPin,6,SerData 'receive data
LCDOut Serdata ' Send to LCD
GOTO Start
END

I have another PIC (16F690) that I have hooked up to my "homemade lcd controller", using serout commands, and I can send data form the 16F690 to the lcd controller without any problems, but one thing that I cannot seem to figure out is how do I send the clear screen command , or any of the other commands that are listed in the PBP manual($FE, ) from the 16F690 to the 16F84A LCD controller?
- 6th February 2006, 04:16
jetpr

My LCD with Pic16f688 (Work good)

INCLUDE "modedefs.bas"
OSCCON=$70
DEFINE OSC 8
define LCD_DREG PORTC
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTA
DEFINE LCD_RSBIT 5
DEFINE LCD_EREG PORTA
DEFINE LCD_EBIT 0
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50
BO VAR byte

ANSEL=0
CMCON0=7
LOW PORTA.4
LCDOUT $FE,1,"LCD 1.0v"
pause 500
HIGH PORTA.2 'Back LED
LCDStart:
serin PORTC.5,N2400,BO
lcdout BO
goto LCDStart
- 6th February 2006, 08:27
chuckles

Thank you for responding, however that is not what I was looking for. Since the PIC16F84A is dedicated to the Parallel LCD module ONLY, I needed a way to send control codes from any other pic to the PIC16F84A via serout commands, in effect I was trying to make my own serial backpack without have to go out and buy it.

For anyone else who reads this thread please ignore the post as I have found my own answers.
- 23rd February 2006, 20:28
afbecker

You problem was the same as mine

Except I am still having trouble making my unit work and a day has passed without anybody contributing significantly to my inquiry.

Perhaps you would be so kind as to share your success.

My post was made to this forum on 22 Feb. 06
- 24th February 2006, 05:37
sougata

1 Attachment(s)

Hope this helps

Hi,

I got this code from the PICBASIC list on the melabs site. I have posted this before here. Posting again. Adapt your code to your specific requirements.

Regards

Sougata
- 24th February 2006, 17:22
Sphere

Try this

@ DEVICE PIC16F84A, HS_OSC, PWRT_ON, WDT_OFF, PROTECT_OFF

DEFINE OSC 20 ' Set speed to 20MHz
TRISB = %00000000 ' All PORTB pins are outputs

' LCD DEFINES
DEFINE LCD_BITS 8
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4 'PORTB.0 is first data
DEFINE LCD_LINES 2 'Number of lines on LCD to be used
define LCD_RSREG PORTA 'Port used for LCD RS Pin
define LCD_RSBIT 3 'Port Pin used for LCD
define LCD_EREG PORTA 'Port used for LCD E pin
define LCD_EBIT 4 'Port Pin used for LCD E Pin
define LCD_COMMANDUS 2000 'Delay between sending lcd commands
define LCD_DATAUS 50 'Delay time between data sent

SerData VAR word
SerPin VAR PORTA.2
TRISA.2=1

pause 1000
LCDOut $FE, 1 'Clear LCD
pause 20
lcdout $FE, 2 'Return to home position
pause 20

GOTO Start

Start:
SERIN SerPin,6,SerData 'receive data
LCDOut Serdata ' Send to LCD
If serdata =5 then gosub clearlcd
GOTO Start
END

clearlcd:
lcdout $FE,$80," "
lcdout $FE,$C0," "
return

So if you send number 5 to your pic it will clear the lcd. From your code ive asumed you have use a 2 line lcd.

Hope it helps
Sphere

lcdout $FE,$80," "
lcdout $FE,$C0," "
when I post the above it has 20 spaces between " " but it is only showing about 4 so add about 20 in your program
- 27th February 2006, 14:44
afbecker

Lcd

Thank you for your replies.

I looked over many of the previous posts by searching this site and realized that my problem was most likely due to trying to use DEBUGIN for input. None of the code examples I saw utilized DEBUGIN. Finally I scrapped the 16F84 as processor, cut 4 data lines from my hardware interface and used a 16F628 with a USART. Using HSERIN (on RB1) as my input and LCDOUT with the 4 line mode, I had success last night.

It looks like the SERIN command was used in one of the examples. Perhaps I will work with it and see what happens.

I think a faulty crystal also complicated my debug process.

In this exercise I learned what a huge amount of information is available on this forum but it helps to search on the correct terminology. Once I discovered that what I am trying to do is referred to as a "backpack", I had a lot of good material to look over.