LCD setting contrast by program

Jan Noman · Joined: 28 May 2005 Posts: 14

Hi everybody !

The contrast on all displays of the EA DOG LCD series can be set only
with a command .How I can change init string in LCD.c driver ?
controller is ST7036 instruction compatible to HD4780

Best regards

Jan

Ttelmah · Guest

Send LCD_INIT first. This ensures the controller is awake, and everything is running. Then just use LCD_SEND_BYTE to send the two contrast control bytes (the high two bits are in the 'power control' command.
I'd suggest storing the value you require for this in an EEPROM location, and allowing the user to 'tweak' them up/down. Though the displays are very stable, there is a tolerance between devices, and especially in cold conditions, the value may need to shift a little.
lcd_init();
lcd_send_byte(0,0x7A);
lcd_send_byte(0,0x52);

Worked on a version some months ago for me as the 'default' values.

You obviously can include these into the 'init_string', but I actually had the bit pattern adjustable, and masked this to form the required bytes.

Best Wishes

Jan Noman · Joined: 28 May 2005 Posts: 14

Very thank You Ttelmah

sorry I'm "green"

....................................
void main()

lcd_init();
lcd_send_byte(0,0x7A);
lcd_send_byte(0,0x52);

.....................................

LCD.c:

..............................................
BYTE const LCD_INIT_STRING[4] = {0x20 | (lcd_type << 2), 0xc, 1, 6};

LCD is dead

other "normal" LCD works fine

what more can I do ?

Ttelmah · Guest

Double check the values from the data sheet. The values I gave were (I think...), the ones I used, but it was quite a few months ago, and on a different screen based on the same controller.

Best Wishes

diegostreetbob · Joined: 05 Sep 2009 Posts: 11

Hello,
i need help with this drivers.

Finally work fine??? Can you send me this drivers,please??

[email protected]

bkamen · Posted: Sat Mar 31, 2012 12:00 pm

diegostreetbob · Joined: 05 Sep 2009 Posts: 11

I don't understand your response, I only asked for help in a resolved topic.

I am thinking of buying this lcd for a pic training for me, and need to be sure before ordering the pcbs.

I'm sorry if someone can be offended.

Regards

Mike Walne · Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK