128x64 GLCD problem on PIC16F887

[adrix]

Hello,
I am using PG12864-F T6963 128x64 graphic lcd, I found all schematics and program codes for pic16f877a. But I am using pic16f887 and when I power up the circuit, the lcd turns on but nothing else happens, maybe I need to change something in the code because I'm using a different mcu? Or maybe there is another problem? I need to make the lcd show something. Thanks in advance for the answers.

Here is the codes:

[PCM programmer]

1. Is this a hardware project or a Proteus project ?

2. If it's hardware, have you ever made the 16F887 do anything, such
as blink an LED once per second ? In other words, does your
board, your ICD programmer, and compiler IDE setup work OK ?

3. He reads and attempt to display a bitmap from a 24LC256 eeprom chip.
Do you have this eeprom chip on your board ? Does it have the
"dog" bitmap in it ? If not, then I suggest that you comment out all
the lines in main() that talk to the eeprom, or that use the data from it.
Just do a test of writing text only.

[adrix]

Thanks for the answer.

1. It is a hardware project.

2. I connected a led and it blinks correctly, so I guess everything with schematics and compilers is ok.

3. I have that chip connected and I imported a hex file:

[dyeatman]

Yes it makes a difference. What does the datasheet say?
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[adrix]

The datasheet doesn't say anything about contrast's voltage. Here s the datasheet: http://www.noodlehed.com/ebay/datasheets/pg12864f.pdf

[ezflyr]

hi,

in the absence of any other information, I would connect the ends of a 10K pot to +5v an GND, and connect the wiper to the GLCD contrast pin. Then adjust the pot until something appears on the GLCD.

John

[dyeatman]

OK, so the datasheet isn't worth much.

Here is some info from a person who has it working and their connections:

[adrix]

Thanks guys I supplied negative voltage to V0 and the lcd works. Just there is a problem that the printed text is not smooth, there are some empty parts in the text, maybe you know how to fix it? Here is a picture:
And here is the program code that I'm using:

[adrix]

Ok I got everything working. The problem was that I was using pic16f887 instead of pic16f877a, so I changed ra4, re0, re1, re2 pins to portbB pins.

[adrix]

Here is another problem:

I want to display a variable graphic lcd, but nothing is happening. Here is the code that I'm trying to use:

[PCM programmer]

What does the GDispPixFontAt() expect for it's 3rd parameter ?
It expects a pointer to a string array of ASCII characters.

What are you giving it ? You're giving it a pointer to an empty array.
The array doesn't have any storage (ie, bytes) allocated to it in the
variable declaration statement. It doesn't have an ASCII string in it,
so it won't work.

Here is what you need to do:

1. Declare an array. Make it sufficiently large enough to hold any
reasonable string that you might put in it. This must include storage
space for the terminating zero byte that marks the end of every string.

2. Declare the variable that you want to display. Initialize it to some
value.

3. Use sprintf() to convert the variable into an ascii string. Give sprintf()
the variable and a pointer to the array. It works like printf(), except it
sends the output to your array, instead of sending it out the serial port.

4. Finally, give the address of the array to your GLCD pixel display
function. Since the array now contains an ASCII string, you should see
it displayed on your GLCD. However, this method has no support for
control characters. You would have to create a glcd_putc() function to
provide support for CR, LF, Backspace characters, etc.

[adrix]

Thank you very much, everything is working. I have one more question: How can I clear only the changing variable, because if I use GDispClrGrh(); it clears all of my text? I tried to make like this:

[adrix]

Maybe I didn't explained the problem quite good, so I took some photos.
Here's what's shown when I turn on the project:


And here's what happens when I increase the temperature:


How can I make that the numbers would smoothly change?

[ezflyr]

Hi,

Those are extremely poor photos, so you aren't doing us any favors! Is the problem that the old data remains when the new data is displayed, showing both old and new superimposed?

John

[adrix]