LCD Control

[Jhdgkss]

i two have purchased an lcd that uses a k0007b criver chip i tried you example of initalising the display manualy not notheing hear is my code can some one check it for me please.

'************************************************* ***************
'* Name : LCD template.BAS *
'* Author : John Hodgkiss *
'* Notice : Copyright (c) 2007 John Hodgkiss *
'* : All Rights Reserved *
'* Date : 17/03/2007 *
'* Version : 1.0 *
'* Notes : *
'* : *
'************************************************* ****************


'Template program for LCD useing a K0007b driver chip
'KS0070b Initialization

'2x16 LCD (KS0070b)
'4 bit mode
'2 lines
'Display=on
'Cursor=off
'Blink=off
'Increment mode
'Entire shif=off

start:
'Power on


'set variables

output portA
Db7 var byte
Db6 var byte
Db5 var byte
Db4 var byte
RS var byte
E var byte
PauseA var byte

PauseC var byte
'set constants

PauseA = 10 ' 100us

PauseC = 200 ' 2ms

'define
DEFINE LCD_DREG PORTA 'LCD data port

DEFINE LCD_DBIT 0 'LCD data starting bit 0 or 4

DEFINE LCD_RSREG PORTA 'LCD register select port
DEFINE LCD_RSBIT 5 'LCD register select bit

DEFINE LCD_EREG PORTA 'LCD enable port
DEFINE LCD_EBIT 4 'LCD enable bit

DEFINE LCD_BITS 4 'LCD bus size 4 or 8

DEFINE LCD_LINES 2 'Number lines on LCD

DEFINE LCD_COMMANDUS 2000 'Command delay time in us

DEFINE LCD_DATAUS 50 'Data delay time in us


pause 400 'pause for 40ms for lcd to start up




'set pins

Db7 = portA.3
Db6 = portA.2
Db5 = portA.1
Db4 = portA.0

RS = portA.4
E = PortB.3

output portA
Output portB
portA = low
PortB = low
setup:

DB7 = 0
DB6 = 0
DB5 = 1
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

DB7 = 0
DB6 = 0
DB5 = 1
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

'set 2 lines 5x7 dots
DB7 = 1
DB6 = 0
DB5 = 0
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

pause PauseA 'pause 100us

'turn display On/Off control

DB7 = 0
DB6 = 0
DB5 = 0
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

'Display cursor off, blink off
DB7 = 1
DB6 = 1
DB5 = 1
DB4 = 1
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

pause 10 ' wait 100us

'clear display

DB7 = 0
DB6 = 0
DB5 = 1
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

DB7 = 0
DB6 = 0
DB5 = 0
DB4 = 1
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

pause PauseC 'pause 2ms

'Entry mode

DB7 = 0
DB6 = 0
DB5 = 0
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

DB7 = 0
DB6 = 1
DB5 = 1
DB4 = 0
'Toggle the Enable line:
PULSOUT E, 100
pause PauseA
E = low

pause pauseC


loop:

Lcdout $fe, 1 ' Clear LCD screen
Lcdout "Hello" ' Display Hello
Pause 500 ' Wait .5 second

Lcdout $fe, 1 ' Clear LCD screen
Lcdout "World"
Pause 500 ' Wait .5 second

Goto loop ' Do it forever




is this correct??

the dispaly does light up but thats it
here is a link to the displays pdf file
http://www.maplin.co.uk/Media/PDFs/N27AZ.pdf

[Jhdgkss]

hi there again i have been up all night trying to get this thing working no luck can some one please have a lok at my code or does anyone know where a example piece of code is. please iam desperate

[jcleaver]

not a expert but my problems has always been with using a higher speed osc
and not reseting lcd_dataus to match the crystal more delay for higher speeds just a thought

[Jhdgkss]

hi there iam not sure what you mean can you explane

[jcleaver]

when i have a problem with the lcd display
it has been the fact that i use a 20 osc
and what works for me is to change line

define lcd_dataus 50

to

define lcd_dataus 200

it just works for me

[Jhdgkss]

hi there thanks for the reply.

how do you know your lcd is in working order, i have ready that if you just provide power to it you should see black boxes is this true. i tried this and all i get is the backlighting up but no boxes.

[Archangel]

hi there thanks for the reply.

how do you know your lcd is in working order, i have ready that if you just provide power to it you should see black boxes is this true. i tried this and all i get is the backlighting up but no boxes.

Power to LCD - pin 1 ground, pin 2 is 5 volts positive, pin 3 center lug of contrast pot. these are the primary power leads, pin 4 R/s bit, pin 5 R/w and must be as mister_e said ground etc etc . . . now pin 15 Power for LED backlight, pin 16 LED backlight ground. Just because led backlight is on does not mean lcd is powered.

[skimask]

Which compiler are you using? 'cause if that code above is PicBasicPro, you really, really need to get reading the PBP manual and learn it.

[mister_e]

You don't have any Black boxes????

Or your contrast POT is crap, or you didn't installed it correctly.. or you forgot. ANY character LCD i know, once connected will produce those Black boxes.

R/W pin is left floating in the air... must be tied to gnd

Some LCD brand may need to tie unused DB<4:0> to Vss or Vdd... have a look to the datasheet