Hi I am hoping I can get a little hand here. I need to understand why I am having such a hard time interfacing this LCD screen to the PIC12F629.

I am trying to use a pre existing set of ASM code that has been written for a PIC16F84..

HERE IS THE LINK. TO KEEP MY POST SHORT

http://sandiding.tripod.com/n7110.html

I have a few things that I don't understand.

Firstly, is there a particular reason why the DTA and CLK pins need to be connected to the RB6 and RB7 pins? I dont see anything with regards to going into some sort of a serial mode inorder to program the LCD it seems the original coder simply send all Zeros to the PORTA and PORTB of the TRISAB registers. Do these pins do somthing special by default? Does the Pic12f629 have this feature? The code from where I can understand is simply bitbangging the data into the LCD controller.

From this.. When I connected my LCD to my PIC12F629 I simply used the 5 IO pins that are available on the chip. GPIO 3 is an input pin only..

The other difference between my design and the link is that I used the CHIPS built in clock at 4mhz. I also don't see this being a problem..

When I power Up the LCD goes all pixels on. and nothing else.

Any help here? THAT WOULD BE AWSOME!

 

NOT even a look see??

 

You would have a better change of getting help if you also post the schematic of your current 12F629 setup connection and the ASM code you are using.

 

If you are using the same code (without modification) then you must use the same pinout as the original project.

How to use the same pinout on a 12F629 with code developed for a 16F84?

 

No I've changed all the pin outs in the code to work for the 629... It's not really that hard instead of PORTA PORTB like the 84 the 629 uses GPIO. So i've coded that and it all corrisponds to the right pinouts on the LCD from the microcontroller.. But I get all black when i get Connected.

The reason why I haven't supplied a picture is because the link is basically exactly how i have it connected. Just without the F84 instead a 629 using the 5 available I/O pins. I'm also using the internal 4mhz Clock.. which should be the same as the external used in the link picture.

Finally I've updated the code to corrispond to the correct GPIO port and TRISIO ports in the code however I still only get a black screen when I plug into my supply which is 3V.

I was wondering why the Author of the original peice used those particular pins on PORT B 6 and 7 which in the data sheet corrisponds to SERIAL CLOCK and SERIAL DATA..

Do those pins do somthing special that I am missing? the links code seems to not implement any special request from those pins besides being output pins. ALSO.. where does the clock output to the LCD in the entire process here?? I don't see any code telling the clock to output to the pin that clock is connected to on the LCD..


Weird anyways. Hope somone can help..

Mo