LCD Control

[Luciano]

Initialization of a 16x2 LCD.

(4 bit Interface).

The first picture is the initialization of a Hitachi HD44780.
The second picture is the initialization of a Samsung KS0077.

Best regards,

Luciano

Hitachi HD44780 initialization
(The above picture)

E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=0

E=1  D7=0  D6=0  D5=1  D4=0
E=1  D7=1  D6=0  D5=0  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=1  D6=1  D5=1  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=0  D6=1  D5=1  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=1  D6=1  D5=0  D4=0

Samsung KS0077 initialization 
(The above picture)

E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=1
E=1  D7=0  D6=0  D5=1  D4=0

E=1  D7=0  D6=0  D5=1  D4=0
E=1  D7=0  D6=1  D5=0  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=1  D6=0  D5=0  D4=1

E=1  D7=0  D6=0  D5=1  D4=0
E=1  D7=0  D6=0  D5=0  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=0  D6=0  D5=0  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=1  D6=1  D5=1  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=0  D6=1  D5=1  D4=0

E=1  D7=0  D6=0  D5=0  D4=0
E=1  D7=1  D6=1  D5=0  D4=0

[boboco]

Hi all,

thanks for the help.

Curious is that the first line functions exactly as it should in every way, only the second line not. If I turn the contrast up to maximal all pixels turn black, though, so at least the line isn't dead.

I've temporarily replaced the Displaytech with another type of unit. (all that work...., sob!) It worked at once so I take it that the Displaytech is bugged in some way. I've ordered a new one and hope that that will work, otherwise I'll have to change the whole construction to use some other. I'll report when I've got the results.

Another short question on LCD control +PBP. If I want to control a 4 liner, which is essentially two complete LCDs in one, I've been doing it by switching both enable lines via resistors from one port and shorting each of the enable lines respectively with another two ports to disable it.

It must be possible to program the PIC so that the selection of two enables is directly possible. (DEFINEs?) I've looked on the board but haven't found anything. Any ideas?

Greetings

Rob

[boboco]

Hi all again,

sorry Luciano, I didn't mention your post. As it would seem, the KS0077 isn't directly compatable to the HD44780. If that is the case, it would be interesting to write code for it as it is similar. If time allows, I'll try it.

Greetings,
Rob

[boboco]

Hi all,

thanks for the help.

Curious is that the first line functions exactly as it should in every way, only the second line not. If I turn the contrast up to maximal all pixels turn black, though, so at least the line isn't dead.

I've temporarily replaced the Displaytech with another type of unit. (all that work...., sob!) It worked at once so I take it that the Displaytech is bugged in some way. I've ordered a new one and hope that that will work, otherwise I'll have to change the whole construction to use some other. I'll report when I've got the results.

Another short question on LCD control +PBP. If I want to control a 4 liner, which is essentially two complete LCDs in one, I've been doing it by switching both enable lines via resistors from one port and shorting each of the enable lines respectively with another two ports to disable it.

It must be possible to program the PIC so that the selection of two enables is directly possible. (DEFINEs?) I've looked on the board but haven't found anything. Any ideas?

Greetings

Rob

[Luciano]

Hi,

Your display is not correctly initialized.
(This is why you get only one line).

In order to use your LCD (KS0070b), you will have
to manually initialize the KS0070b before you call the
first PicBasic LCDOUT.

Below you can find the pseudo code + a table.

Best regards,

Luciano


See PDF page 32 for the initialization of the KS0070B in 4 bit mode
http://www.ee.oulu.fi/research/tklab...river-3316.pdf

KS0070b Initialization

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

(Pseude-code, same as the table below).

==============================================
Power on  
(PIC and LCD module).
==============================================
Wait 40 ms
==============================================

(Function Set)

------------------
Set the LCD pins: 
DB7,DB6,DB5,DB4 = 0010

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 
------------------
Set the LCD pins:
DB7,DB6,DB5,DB4 = 0010

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs)
------------------
Set the LCD pins:
DB7,DB6,DB5,DB4 = 1000 (2 lines, 5x7 dots)

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs)
------------------
==============================================
Wait 100 µs
==============================================

(Display On/Off Control)

Set the LCD pins: 
DB7,DB6,DB5,DB4 = 0000 

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs)
 
Set the LCD pins: 
DB7,DB6,DB5,DB4 = 1100 (Display on, cursor off, blink off).

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 

==============================================
Wait 100 µs
==============================================

(Clear display)

Set the LCD pins:
DB7,DB6,DB5,DB4 = 0000 

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 

Set the LCD pins:
DB7,DB6,DB5,DB4 = 0001

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 

==============================================
Wait 2 ms
==============================================

(Entry Mode Set)

Set the LCD pins:
DB7,DB6,DB5,DB4 = 0000

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 

Set the LCD pins:
DB7,DB6,DB5,DB4 = 0110 (Incremet mode, entire shif off). 

Toggle the Enable line:
PULSOUT Enable_Pin,100 (min.100 µs) 

==============================================
Wait 2 ms
==============================================


End of the KS0070b Initialization.

[boboco]

Hello Luciano,

Thanks, Pal. Now it works. And I've learnt something new.

Best greetings,

Rob

[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

[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