Re: [avr-gcc-list] Re: global variables - II

[Mikael Krus]

Do you include all needed sections when creating your binary?
example:
avr-objcopy -j .text -j .data -O ihex input_file output_file.hex

I guess your character array (or string) goes into the .data section.

/Mikael Krus

Stein Haaland wrote:

> My problem is not really connected to the EEPROM writing, more
> to the definition of global variables, thus the subject.
>
> The code snippet below illustrates the problem. The Port 
> (on a STK 500) does not sequentially output the character 
> string as expected; it rather toggles between 0x00 and 0xFF. 
>
> I can set the port to any value, using local variables.
> Is there anything I have misunderstood in the use of global 
> variables and avr-gcc ?
>
> ----
> #  include <avr/io.h>
>
> char text[] = "This is a test";    // test string or uint8 array or...
>
>
> void wait(uint16_t ms)
> {
> ...
> // a multiple do while loop to create a delay. Works !
> }
>
>
> void write_text_to_port() 
> {
>  uint8_t i;
>  
>  for (i=0; i<10; i++) {
>    PORTB = ~text[i];            // Port B = character[i]
>    wait(400);                   // ...wait....
>    PORTB = ~0x00;               // turn of all leds
>    wait(400);                   // ... wait ...
>  }
> }
>
>
> int main(void)
> {
>  DDRB = 0xFF;                   // set to output
>
>  write_text_to_port();
> }
>
> ---
>
>
>  
>
> > ...
> > Your character matrix is very large. Isn't it in fact 
> > larger than the available amount of SRAM in AT90S8515????
> > ..
> > /Mikael Krus
> >    
>
> Yes, thanks for pointing out. This is a side issue though.
>
>  
>
> > ..
> > Is DDRC == 0xFF ? 
> >    
>
> Yes, DDR is set. 
>
>  
>
> > If you want to store data in the EEPROM once, you could also build 
> > a Intel Hex File ... 
> > Bernard 
> >    
>
> This is my intention - any examples references on how to do this ?
>
>
> (Sys :
> MDK Linux 10.0.
> avr-gcc (GCC) 3.3.2 
> objcopy 2.14 20030612
> uisp version 20040311
> STK500 testboard, AT90S8515)
>
> SEH.
>
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