Thread: Scrolling Characters Output

Hey guys. Great forums.

C programming n00b here hoping some of you can help me with a problem I'm working on.



The overall goal I'm trying to achieve is scroll every character of the alphabet on an LCD screen.

I've already written two functions that can print out definitions (which can be set to the hex table they represent) and another function where i can simply print out anything I have in quotes. However, I'd like to scroll through the entire alphabet and I'm a noob so I'm no too sure how to do this.

Some ideas I have are:

Code:

char characHI[] = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
char characLO[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
int characNU[] = {'1','2','3','4','5','6','7','8','9','0'};
int i;

for ( i = 0; i < 10; ++i )
write_lcd(REG, characNU[i]);

The write_lcd function prints out characNU as a test (for the numbers). REG is = 1. But this doesn't work. I'm just throwing ideas out right now but any help is appreciated. Thanks in advance.

-Duke

Originally Posted by Salem

> and another function where i can simply print out anything I have in quotes.
So this bit works right?

> However, I'd like to scroll through the entire alphabet
And this bit doesn't ?

Unless your LCD has a specific command to scroll (without assistance from your program), you basically have to do it yourself and regenerate the entire display from scratch for each scrolling step.

Say

Code:

char msg[] = "abcde";

Then a loop
for ( i = 0 ; i < 5 - 3 ; i++ ) {
  displaySubString( &msg[i], 3 );  // abc, then bcd, then cde
}

Ah i didn't think of it that way. Brilliant!!

Yes the function that is made where I can print anything out in quotes works. I can put in words "hello" and it will print it out respectively.

Thanks for the quick response. I've been lookin for a good programming board for a while now and I think I just found it.

another quick question.

displaySubString would act as what? a function?

to make myself a bit more clear:

Code:

char displaySubString;
int i;

char msg[] = "abcde";

for ( i = 0 ; i < 5 - 3 ; i++ ) {
  displaySubString( &msg[i], 3 );  // abc, then bcd, then cde
}

lcd_puts(displaySubString);

and im getting an error: banner.c:132: error: called object '&displaySubString' is not a function

Originally Posted by Salem

Yes, displaySubString() is a function, which displays the specified number of characters using whatever LCD specific function you choose.

Hmmm then why am i getting this error?

because you didn't make it yet. it's not a standard function.

omg im a n00b.

k i just replaced it with my lcd_puts function.

what does the 3 represent in:

Code:

msg[i], 3

Originally Posted by Dukefrukem

omg im a n00b.

k i just replaced it with my lcd_puts function.

what does the 3 represent in:

Code:

msg[i], 3

Based on the example, I am guessing the number of characters you can display at once. Again, based on your function to the LCD.

Originally Posted by QuantumPete

Yeah, and that kind of spelling literally screams it. :S

QuantumPete

Well obviously I'm not a newbie to internet forums. Im just trying to exaggerate my level of C programming.