Posted on October 17, 2006 at 12:51I have found using the 16k compiler that to pass an unsigned long variable to a function I have to prototype the function properly or the value passed to the function is not always correct.
Sadly I have no meaningful debug on this circuit or I would investigate further. The code is as follows:
void delay(unsigned long len){
unsigned long tstart = 0;
unsigned char tnew = 0;
for(tstart = 0; tstart < len; tstart++){
tnew = 0;
for(tnew = 0; tnew < 2; tnew++);
WDGCR = 0xff;
for(tnew = 0; tnew < sizeof(len); tnew++){
SCI1DR = (unsigned char) (len >> (tnew * 8));
while(!(SCI1SR & 0x40)) WDGCR = 0xff;
}
}
PDDR &= 0xef;
}
This gets locked in an endless loop unless I include the following line at the start of the program:
void delay(unsigned long);
The clue is that the final line before returning (i.e. outside both for loops) is not executed so I presume the test tstart < len always fails.
I have sent the contents of the variable along RS232. When I send decimal 15 I get 26 00 00 00 when I left-shift the variable and CD 4F 06 00 when I right-shift. Either way, the test fails. When the function is properly protoyped the test passes and the code executes as I would expect.
