Hi,
I would use something like:
for (i=0; i<4; i++)
char_counter[i] = ((unsigned char*)&long_counter)[i];
for (i=0; i<4; i++)
((unsigned char*)&long_counter)[i] = char_counter[i];
Hynek
Dne 4.5.2011 4:08, stof...@skulp.net napsal(a):
Hi, I have to transmit an unsigned long as four bytes, so I split them up
and join them again, but with the folowing example code, I get overflow at
long_counter>32767 - can any of you give me a clue how to do it right?
<http://code.google.com/p/kodak-timer/source/browse/ir_test/four_unsigned_char_to_unsigned_long.c>
unsigned char i;
unsigned long long_counter;
unsigned char char_counter[4];
void main(void) {
unsigned char len;
unsigned char lcd_buf[16];
OSCCONbits.SCS = 0x0; // System Clock Select bits = External
oscillator
OSCCONbits.IRCF = 0x7; // Internal Oscillator Frequency Select
bits 8
MHz (INTOSC drives clock directly)
lcd_init();
while (1) {
for (long_counter = 0; long_counter< 0xffff0000; long_counter
+= 50) {
// split long_counter to four unsigned char's
for (i = 0; i< 4; i++) {
char_counter[i] = (long_counter& (0xff<< (i *
8)))>> (i * 8);
}
// convert them to unsigned int again
long_counter = char_counter[0] | (char_counter[1]<< 8)
|
(char_counter[2]<< 16) | (char_counter[3]<< 24);
sprintf(lcd_buf, "%lu", long_counter);
debug(lcd_buf);
}
}
}
P.S. Compiling for pic18f2550
- kristoffer ek
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