topic Wierd wierd function behavior... - MCS08GT32A in 8-bit Microcontrollers

Wierd wierd function behavior... - MCS08GT32A

Rubberduck — Thu, 11 Dec 2008 20:32:43 GMT

I really hope someone can tell me whats is going wrong, im fairly new to c/codewarrior and to the HCS08GT32A microcontroller. The following doesn't make any sense me .

my main looks like this:

void main(void)
{
char *test_str = "111222333";

system_setup();

for(;
{
display_string_still(test_str);
}
}

void display_string_still(incomming_str)
{
unsigned char disp_buffer[BUFFER_LENGTH][BUFFER_HEIGHT]; //BUFFER_LENGTH = 4 BUFFER_HEIGHT = 10
unsigned char i;
unsigned char j;

display_string_rolling_left(incomming_str);

for(i = 0; i < BUFFER_LENGTH; i++)
{
    for(j = 0;j < BUFFER_HEIGHT; j++)
    {
      disp_buffer[i][j] = 0b00000000;
    }
}

}

The above code doesn't work... But if I out comment the two for-loops it will run perfectly(display_string_rolling_left(incomming_str) is then working and making the text roll on my LEDS). But why?... First of all the for-loops occurs after the display_string_rolling_left(incomming_str) function call. To my knowledge these things should be executed sequential? And since the disp_buffer is a local variable, it shouldn't influence anything out of this void display_string_still() scope?.. Or am I missing something(which problerly is the case since im new in this microcontroller world ) ?

Thanks in advance!

Rubberduck

Added p/n to subject.

Message Edited by NLFSJ on 2008-12-17 07:47 AM

Re: Wierd wierd function behavior...

Lundin — Thu, 11 Dec 2008 21:55:33 GMT

First of all, 0b00000000 is not valid C and will not compile on any standard C compiler.

Apart from that, I suspect that the problem is related to a stack overflow. You are allocating 40 bytes on the stack at each function call.

What does "going wrong / doesn't work" mean, more specifically?

Re: Wierd wierd function behavior...

Rubberduck — Fri, 12 Dec 2008 02:31:50 GMT

You were right, it was the stacksize that was too small, so it runs again now Thanks alot for your answer!

What i meant with the going wrong thing, was that the display_string_rolling_left(incomming_str);
was the place where the stack overflow was occuring, so i was just confused, since a change in function A made function B go mad, but I learned something, and thanks again