Re: [avr-gcc-list] Problem to control S1D13305 (SED1335-Epson Controller) with using ATmega32

[Blake Leverett]

Hello Sach,

I don't know much about the SED1335, but I can give some advice.  See my 
comments below.

Blake

On Friday 04 July 2008, Sach wrote:
> hi,
>
> I am trying to control S1D13305 (SED1335-Epson Controller) based Graphic
> LCD with using AVR ATmega32 microcontroller.
>
> I have written the demo code in c language for it in AVRStudio4. The
> problem is i am not getting any output on LCD. I have read the datasheet of
> SED1335 many times but i can not understand in details how to initialize
> LCD, about delay of LCD, contrast port values etc.
>
> Please help me with this.
>
> Regards,
> Sachin Rathod,
> India.
>
<snip>

> void LcdInit(void)
> {
>       CtrlPort |= (RD|WR);
>       CtrlPort &= (~CS)|(~RST)|(~FS1);
This won't work. It should be 
        CtrlPort &= ~(CS|RST|FS1);
>       Delay(i);
>       CtrlPort |= RST;
> }
<snip>

This Delay() funtion will be entirely optimized out, and won't even get 
called.  You can fix it by using a volatile counter as shown below, or use 
the avr-libc's delay() function, which is better.
> void Delay(unsigned int counter)
> {
        volatile cnt = counter;
        // change counter to cnt below:
>       while(counter)
>       {
>               counter = counter - 1;
>       }
> }