LCDOUT probs

HI there this is the first time i have tried driving an lcd i have read the manual but i still canot get the thing working.
Here is my code

start:

pause 1000 'wait for lcd to start up
lcdout $FE, 1 'clear screen
lcdout $FE, 2 'return to home
lcdout $FE, 1, "Welcome" 'write welcome on the screen

pause 2000

goto start
end if


i have built the circuit based on the one in the pbp maunal

but still no luck, nothing, i have checked all my connections but still nothing the lcd i am using is from here http://www.maplin.co.uk/module.aspx?...9&doy=9m3#spec

please can some one please steer me in the right direction, thank you for your time.

Make certain you have all your DEFINES set up properly to tell PBP just
what pins you have connected to what.
Also, use some command and data delays.

Below is a header file I use. It works with every display I hook up.
You will have to change your pin definitions, of course.

DEFINE LCD_DREG PORTH
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTH
DEFINE LCD_RSBIT 5
DEFINE LCD_EREG PORTJ
DEFINE LCD_EBIT 2
DEFINE LCD_RWREG PORTH
DEFINE LCD_RWBIT 4
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 3000
DEFINE LCD_DATAUS 300

Quote:

---

Originally Posted by Jhdgkss

start:

pause 1000 'wait for lcd to start up
lcdout $FE, 1 'clear screen
lcdout $FE, 2 'return to home
lcdout $FE, 1, "Welcome" 'write welcome on the screen

pause 2000

goto start
end if

---

Is that your whole program?

yes thats the whole code. how do i set the define's so that my data will use portA like in the manual and the enable is on portb.3 i thought it would just adopt the standard setting automatacly unless told otherwise. iam useing a pic64f84a

Just follow my example. It should be pretty explanatory.

In my example, I use PORTH as the data register
The LSbit is tied to bit 0 (PORTH.0)

The R/S pin is tied to PortH.5

E is tied to PORTJ.2 etc

Charles,

Is there any particular reason that the 4 data bits and the controlling pins (ie. E, RW, RS) should be on different ports as I seem to see in most examples??

Or can they be "defined" to the same port without problem?


Hoops

They can be defined on the same port. The only limitation that I'm aware of is that the DATA lines must start on a nybble boundary (either on bit 0 or 4)of a port.

hi thanks for your replys.
so to alter this code to run on a pic16h84 witch has o port h only A and B i make the following changes

start:
DEFINE LCD_DREG PORTA
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTA
DEFINE LCD_RSBIT 4
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 3
DEFINE LCD_RWREG PORTA
DEFINE LCD_RWBIT 4
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 3000
DEFINE LCD_DATAUS 300

Main:

pause 1000

LCDOUT $FE, 1
LCDOUT $FE, 2, “Hello”
pause 1000
goto Main


with connections

1 - VSS
2 - VDD
3 - VC
4 - RS - PortA.4
5 - R/W - portA.4
6 - E - PortB.3
7 - Db0 -open
8- DB1 - open
9 - DB2 - open
10 DB3 - open
11 DB4 - portA.0
12 DB5 - portA.1
13 DB6 - portA.2
14 DB7 - portA.3


could some one please have a look at my data sheet for the display and check hat this setup will work with it
http://www.maplin.co.uk/Media/PDFs/N28AZ.pdf
thank you for your patience your help has shed a lot of light on the subject of lcd's for this newbie.

Assuming you have a Pull-Up resistor on the PORTA.4 pin, i think you MUST set them to LOW yourself.

You don't need to use the LCD R/W pin, just ground it and remove the according DEFINEs


AND you have two things on PORTA. RW and RS :eek:

hi there thanks for the reply. ia have resistor on that pin

i have noticed the prob with rw and rs
here are my changes in code

start:

portA = low
PortB = low
DEFINE LCD_DREG PORTA
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTA
DEFINE LCD_RSBIT 4
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 3

DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 3000
DEFINE LCD_DATAUS 300

Main:

pause 1000

LCDOUT $FE, 1
LCDOUT $FE, 2, “Hello”
pause 1000
goto Main


with connections

1 - VSS
2 - VDD
3 - VC
4 - RS - PortA.4
5 - R/W - Ground
6 - E - PortB.3
7 - Db0 -open
8- DB1 - open
9 - DB2 - open
10 DB3 - open
11 DB4 - portA.0
12 DB5 - portA.1
13 DB6 - portA.2
14 DB7 - portA.