Hi,
My solution would be:
#include <stdint.h>
union U8x4_n_U32
{
uint8_t u8[4];
uint32_t u32;
};
union U8x4_n_U32 u8x4_n_u32;
// uint32_t to array of uint8_t conversion
u8x4_n_u32.u32 = 0xA0459201;
/**********************************************
** Now you can access the individual bytes as
** u8x4_n_u32.u8[0]
** u8x4_n_u32.u8[1]
** u8x4_n_u32.u8[2]
** u8x4_n_u32.u8[3]
**********************************************/
AND
// Array of uint8_t to uint32_t conversion
u8x4_n_u32.u8[0] = 0x01;
u8x4_n_u32.u8[1] = 0x92;
u8x4_n_u32.u8[2] = 0x45;
u8x4_n_u32.u8[3] = 0xA0;
/**********************************************************
** Now you can access all the bytes as unsigned long using
** u8x4_n_u32.u32
***********************************************************/
Krish
On Thu, May 5, 2011 at 10:48 AM, Hynek Sladky <ec...@centrum.cz> wrote:
> 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>
>
> <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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