LCD contrast

Hi,

If a LCD is 4 lines by 20 characters and we turn the contrast way up, do we get:

- 1 line contrast squares, 1 line blank, 1 line contrast squares, 1 line blank.

or

- 4 lines contrast squares.

It looks like I'm as successful getting this CASIL CCM-2040CSL v2.0 LCD going as I was getting registers shifting.

What is the difference between using a 4 bit bus vs an 8 bit bus? I am trying to use 8 bits 'cause, well I have them. I figured that 8 bits would either give faster communication or some other advantage.

I am running this on a 16F628 at 20MHz.

Robert
:)

Euh, nevermind...?

I was testing the 4 vs 8 bit bus technique and it works using 4 bits.

Oh well, I have 4 spare pins on my PIC.

Robert
:)

Hi robert,

If i refer to my, i'll get :

- 1 line contrast squares, 1 line blank, 1 line contrast squares, 1 line blank.

Quote:

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What is the difference between using a 4 bit bus vs an 8 bit bus? I am trying to use 8 bits 'cause, well I have them. I figured that 8 bits would either give faster communication or some other advantage.

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i always use LCD in 4bit mode. This way you save I/O ( duh! ). It can be more faster... it has too but... who will see it??? i think nobody ;)

Don't forget the LCD Defines... 4 lines and blah blah blah. Be sure you disable analog comparator and place pull-up on RA4 pin.

In my case i'll place all LCD pins on PORTB. The define lines will look something like this

Code:

---

'********************** Lcd pinout ******************************
'
'                  B0-B3 : Data port
'                    B4 : Rs Bit             
'                    B5 : E Bit             
'
define LCD_DREG PORTB  ' Set data pin of LCD to
define LCD_DBIT 0      ' PORTB.0-PORTB.3
define LCD_RSREG PORTB  ' Set RS bit of LCD to
define LCD_RSBIT 4      ' PORTB.4
define LCD_EREG PORTB  ' Set E bit of LCD to
define LCD_EBIT 5      ' PORTB.5
define LCD_LINES 4

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Hello Robert

I am writing you for asking about the datasheet of CASIL CCM-2040CSL v2.0 LCD because I have one of this component but I can't find your datasheet.

Please, can you send me a copy if you have it?

Sorry by me english, I am studing :(



Chikyto

Quote:

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Originally Posted by Demon

Hi,

If a LCD is 4 lines by 20 characters and we turn the contrast way up, do we get:

- 1 line contrast squares, 1 line blank, 1 line contrast squares, 1 line blank.

or

- 4 lines contrast squares.

It looks like I'm as successful getting this CASIL CCM-2040CSL v2.0 LCD going as I was getting registers shifting.

What is the difference between using a 4 bit bus vs an 8 bit bus? I am trying to use 8 bits 'cause, well I have them. I figured that 8 bits would either give faster communication or some other advantage.

I am running this on a 16F628 at 20MHz.

Robert
:)

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