CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support

16x2 LCD powerup question.

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
jai



Joined: 12 Apr 2011
Posts: 11

View user's profile Send private message

16x2 LCD powerup question.
PostPosted: Thu Jun 30, 2011 7:09 am     Reply with quote

Hi All,

I am working on a project where the display is JHD-162A. Which is a 16x2 line LCD module.
It works fine. The problem is when i turn power on first it displays black box on one line. After that it works fine. My question is how can i avoid that.
I just want the display to be blank at power on.
I also found that it does not have anything to with LCD init as the problems occur even when i don't program to use the LCD.

Thanks for any help,

Regards
Jai.
jai



Joined: 12 Apr 2011
Posts: 11

View user's profile Send private message

PostPosted: Thu Jun 30, 2011 7:20 am     Reply with quote

I found that the VEE voltage was 0 Volt.
When i increase the voltage to greater than 0.5 Volt.
Some of the characters do not properly appear.

Regards
Jai
temtronic



Joined: 01 Jul 2010
Posts: 9246
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Thu Jun 30, 2011 8:17 am     Reply with quote

All(most) LCDs have an internal powerup sequence and a default setting(usually 1 line).The LCD manual will explain this.
You can't get around this unless you reprogram the LCD chip itself which is not an option.

This procedure is inside the LCD, it does not have anything to do with the driver you use.

The LCD 'contrast' pin (usually pin 3) has to be adjusted for the best 'look' based on the angle the viewer will see it from. Most LCD modules will have a pot allowing you to 'set once and forget' this adjustment.

hth
jai



Joined: 12 Apr 2011
Posts: 11

View user's profile Send private message

PostPosted: Fri Jul 01, 2011 12:28 am     Reply with quote

Thanks for the input.

regards,
jai.
foxOnTheRun



Joined: 17 Apr 2010
Posts: 43

View user's profile Send private message

PostPosted: Fri Jul 01, 2011 3:01 am     Reply with quote

Hi, the black line appears if the LCD is not receiving an init sequence, to avoid this I do in my code:

lcd_init();
setup_oscillator(OSC_8MHZ);

rst(); // initialize vars, counters, etc

And the display is immediately driven, so no garbage is actually displayed

;)
_________________
Listen, why don't you relax? Take a pill, bake a cake or go and read the encyclopedia.
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group