Convert hex values to float

Hello Dhanush,

I am a bit confused here. You are converting a char string to float. Then due to the fact that the controller is little endian, it is not correct. My confusion is how are you interpreting the data in char as?

Regards
Amit

Amit,
How I interpret it is that the value is already a binary float, just represented by four hex bytes. Endianness comes into play when the value is typecast as a float and the bytes are in the wrong order...
-Veikko

Hello Veikko

I thought the same but then the value 8 appearing at two places should have had the same value.

Regards
Amit

Hello Amit
Thanks a lot :)
I resolved the problem and the problem was of data format only as you said that the controller is little endian. I reversed the sequence of data and got the solution.

Hello Dhanush,

Sorry, but still not clear. Can you put the final format of the values that got the correct data?

Regards
Amit

Amit Ashara said:

the value 8 appearing at two places should have had the same value

Only if one assumes it's a conversion to/from an ascii string or similar... I think the term "hex string" was misleading in the first place, when I think this is what it's all about:

#include <stdio.h>

int main(void) {

        char hiawatha[4] = {0x41, 0x07, 0xae, 0x14};
        char big_chief[4] = {0x14, 0xae, 0x07, 0x41};

        printf("%.2f\n", *((float*)hiawatha));
        printf("%.2f\n", *((float*)big_chief));

        return 0;
}

/* Prints out:
***:~ veikko$ ./a.out
0.00
8.48
*/

Hello,

I have a similar problem. I've tryed your solution bur it didnt work.

I read 4 Hex values 0xA0 0xEC 0xA4 0x40

I've saved this values on 2 arrays

char Voltage[4] = {0xA0 0xEC 0xA43 0x40}, VoltageAux[4]={0x40, 0xA4, 0xEC ,0xA0};

to convert i'm doing

Volt = *(float*)Voltage; // result 2.16734...e-38

Curr = *(float*)VoltageAux; //result 1.50611...e-38

I'm using a TMS320F28377S.

Any idea about what could be the problem ?

Thank you.

Hello Bruno

You would need to check on the TMS320 forum (C2000 forum)

Regards
Amit

It did not work because you mistyped the 3rd element on char Voltage[4]

0xA43

Otherwise, 0x40a4eca0 would give you 5.1539 volts.