Help in programming Graphic LCD with 18F4520

[hemnath]

Hi,
I'm interfacing KS0108 GLCD with PIC18F4520 controller. Compiler: CCS C 4.114. I have read the datasheet of KS0108 GLCD. But still i feel difficult in writing the code. I want to display "Hellow" in GLCD.

As a newbie in Graphic LCD, i tried CCS example and it was working good.

All i want to do is, making my font size as flexible. In CCS C compiler, there are only 2 font sizes which are 5x7 and 10x14. There are some instances where i will display some big size characters than 10x14. Also in CCS, there are inbuilt commands to use the X and Y addresses.

Now I'm writing the code as mentioned in datasheet. I want to display a character 'H' in the display. Please check initialization is correct? how to define hex values for character 'H'? Please help.

[hemnath]

After struggling a bit, i have finally displayed a character 'H' in the Graphic LCD.

Could anyone explain me a logic how to display a character 'H' with 15 x 15 height and width ???

Or do have any glcd library??

Please help!!!

[hemnath]

any help please!!! Totally lost.

How can i use "glcd.c" to display a font size of 15 x 15?

any help would be appreciated much

Thanks in advance

[temtronic]

First place I'd go to is the manufacturer of the LCD Module and see what resources they offer.They may have a program that generates the required bit patterns for the pixel patterns for whatever you're looking for.
The datasheet for the module should have most if not all of the details you need.
If not, try 'Google' for 'pixel generator' program for your module.
Obviously you're not the first to use it, so odds are good someone else has done it and may have a 15x15 'driver ' for you.

hth
jay

[ezflyr]

Hi,

It's really not that hard! Study how the 5x7 character function works, and expand it! Each column of your font will require 2 bytes of data, by 15 rows, for a total of 30 bytes of data. I used 'GLCD Font Creator' to create my character data for this purpose.

I read in the data column by column, and then use 'Make16' to create a 16 bit word for the column data. Work thru the word using the 'bittest()' function to see of the bit is 0 or 1, and then set the pixel appropriately! Repeat for all columns, and you are done!

I'd share my routine, but I'm traveling in China now without my CCS code. If you are really still stuck, I can post my code in about 10 days when I return to the US.

John

[hemnath]

Thanks temtronic & ezflyr for your kind reply.

I have used 'GLCD Font Creator' to create the character data.

For character 'H' size of 15 x 15, the data is,

const unsigned char data[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x3F, 0x7F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

But the problem im facing is, for first 15 values, the page would be 0xB8 and for next 15values, the page would be 0xB9. Am i right???

@ezflyr: If you could post the sample code of yours, i could learn from your code. I have studied how 5 x 7 works and implemented. In the case of 5 x 7, i could use only one page. But for 15 x 15, in need of using 2 pages to display a character. I really don't find a logic. That's where i got stucked. Waiting for your reply guys.

Thanks you

[ezflyr]

Hi,

I'll post my code when I return from my travels. In the meantime I recommend you get some graph paper, and figure out how the data you've got represents a given character. Your 15x15 character is going to be two bytes "tall", by 15 2-byte groups wide. Just like the 5x7 character function, you need to loop thru all of the vertical bits, and all the horizontal byte groups. Seriously, do it with graph paper, and I'll bet you can see it yourself!

BTW, I'm confused about your reference to 'pages'? Can you please elaborate on this?

John

[Ttelmah]

On old compilers, and with PIC16's, you had to 'worry' about memory pages. However provided you compiler is within the last few years old, with the PIC18, you don't have to worry. The compiler will happily generate arrays several KB in size, and handle paging for you. However you need to be remembering just how much memory the font will use. Characters 32 to 127, in 15*15, will use 96*30bytes = 2880bytes of the ROM.

You can basically take the font array as generated by GLCD font creator, and just change the declaration line only to:

const int8 my_font[] {

and paste the data directly from the program. The syntax is correct for CCS.
Each character takes 30 bytes to store (15*2 bytes), versus the 5 bytes in the original font. Obviously 'no_chars' will depend on how many characters you encode.

The large amount of ROM needed, is why the demo, sticks to a font that can fit each line in a single byte. Remember the standard code can display the font multiple size if required, so set 'size' to 3, and it displays 15*21 text. The point about coding a larger font, is that it allows much finer detail.

Then 'PixelData' has to expand to 15*int16, instead of using bytes (simpler - see below).
The 'wrap' point has to test at +15, not +5.
The memcpy's, have to copy 30bytes into PixelData.
If you just use a single, single dimensional array, the copy becomes:
memcpy(pixelData, my_font+((*textptr - ' ')*30), 30);

Then j=0 j<15
Then k=0 k<15

Because you change 'PixelData' to an int16, rather than int8, each line in the array still holds the data for each line in the characters. Much simpler.

That is it.

Best Wishes