Hexadecimal Data Convert to signed int32

Question

Rasit 2023-11-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2050222-hexadecimal-data-convert-to-signed-int32

评论： Les Beckham 2023-11-22

Hello everyone!

I'm try to convert from hexadecimal data to signed int32. Here is my matlab code:

----------------------------------------------------------

Gyro_const = 1.08507e-6;

rawdata = [

"0a" "31" "00" "00"

"14" "cf" "ff" "ff"

"8f" "13" "00" "00"

"36" "ce" "ff" "ff"

"cf" "1a" "00" "00"

"83" "f3" "ff" "ff"

"9e" "fc" "ff" "ff"

"82" "eb" "ff" "ff"

"17" "1b" "00" "00"

"c9" "da" "ff" "ff"

"65" "1e" "00" "00"

"14" "dc" "ff" "ff"

"e8" "29" "00" "00"

"c9" "cb" "ff" "ff"

"29" "1b" "00" "00"

"32" "ef" "ff" "ff"

"80" "f8" "ff" "ff"

"b0" "ec" "ff" "ff"

"29" "23" "00" "00"

"09" "cf" "ff" "ff"];

%for i = 1:size(rawdata,1)

for i = 1:2

data = rawdata(i,:);

fprintf("non Inverted Data\n")

[data(1),data(2),data(3),data(4)]

fprintf("Inverted Data\n")

[data(4),data(3),data(2),data(1)]

double(int32(hex2dec(strcat(data(4),data(3),data(2),data(1)))))*Gyro_const

end

----------------------------------------------------------

I run this code in 2 steps and output like this:

ans =

1×4 string array

"0a" "31" "00" "00"

Inverted Data

ans =

1×4 string array

"00" "00" "31" "0a"

ans =

0.0136

-------------------

non Inverted Data

ans =

1×4 string array

"14" "cf" "ff" "ff"

Inverted Data

ans =

1×4 string array

"ff" "ff" "cf" "14"

ans =

2.3302e+03

Of these two values "0.0136 ","2.3302e+03" comes from "0000310a", "ffffcf14" hex values.

These values convert via hex2dec() built-in function.

I manually check hex value to decimal conversion but there are problem for me, this problem caused by hex2dec() function: For example:

hex2dec(strcat("00","00","31","0a")) -> 12554 This is true value for me. But the second iteration conversion is

hex2dec(strcat("ff","ff","cf","14")) -> 4.2950e+09 This is wrong value for me.

I think this problem based on the hex2dec int32 conversion. So my question how can I the hex2dec function output:

I mean, I know that this conversion hex2dec(strcat("ff","ff","cf","14")) actually -> -12524 value.

But my result is 4.2950e+09.

My question:

How can I set hex2dec function output, signed int32? or is there a any different solution for my problem.

Kind Regards.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Les Beckham 2023-11-21

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2050222-hexadecimal-data-convert-to-signed-int32#answer_1357237

编辑：Les Beckham 2023-11-21

在 MATLAB Online 中打开

The hex2dec function assumes unsigned integer unless you tell it otherwise. You can either typecast the unsigned result to signed or use a suffix (e.g. 's32') on the string or char vector that you pass to hex2dec. I've shown both approaches below. Note that using the suffix only works on R2020a or higher.

Gyro_const = 1.08507e-6;
rawdata = [   
    "0a"    "31"    "00"    "00"
    "14"    "cf"    "ff"    "ff"
    "8f"    "13"    "00"    "00"
    "36"    "ce"    "ff"    "ff"
    "cf"    "1a"    "00"    "00"
    "83"    "f3"    "ff"    "ff"
    "9e"    "fc"    "ff"    "ff"
    "82"    "eb"    "ff"    "ff"
    "17"    "1b"    "00"    "00"
    "c9"    "da"    "ff"    "ff"
    "65"    "1e"    "00"    "00"
    "14"    "dc"    "ff"    "ff"
    "e8"    "29"    "00"    "00"
    "c9"    "cb"    "ff"    "ff"
    "29"    "1b"    "00"    "00"
    "32"    "ef"    "ff"    "ff"
    "80"    "f8"    "ff"    "ff"
    "b0"    "ec"    "ff"    "ff"
    "29"    "23"    "00"    "00"
    "09"    "cf"    "ff"    "ff"];
%for i = 1:size(rawdata,1)
for i = 1:2
    data = rawdata(i,:);
    fprintf("non Inverted Data\n")
    [data(1),data(2),data(3),data(4)]
    fprintf("Inverted Data\n")
    [data(4),data(3),data(2),data(1)]
    % double(int32(hex2dec(strcat(data(4),data(3),data(2),data(1)))))*Gyro_const
    double(typecast(uint32(hex2dec(strcat(data(4),data(3),data(2),data(1)))), 'int32')) * Gyro_const
    double(hex2dec(sprintf('0x%s%s%s%ss32', data(4:-1:1)))) * Gyro_const
end
non Inverted Data
ans = 1×4 string array
    "0a"    "31"    "00"    "00"
Inverted Data
ans = 1×4 string array
    "00"    "00"    "31"    "0a"
ans = 0.0136
ans = 0.0136
non Inverted Data
ans = 1×4 string array
    "14"    "cf"    "ff"    "ff"
Inverted Data
ans = 1×4 string array
    "ff"    "ff"    "cf"    "14"
ans = -0.0136
ans = -0.0136

3 个评论
显示 1更早的评论隐藏 1更早的评论

Stephen23 2023-11-21

在 MATLAB Online 中打开

Note that the loop is not required:

format long G
Gyro_const = 1.08507e-6;
rawdata = [   
    "0a"    "31"    "00"    "00"
    "14"    "cf"    "ff"    "ff"
    "8f"    "13"    "00"    "00"
    "36"    "ce"    "ff"    "ff"
    "cf"    "1a"    "00"    "00"
    "83"    "f3"    "ff"    "ff"
    "9e"    "fc"    "ff"    "ff"
    "82"    "eb"    "ff"    "ff"
    "17"    "1b"    "00"    "00"
    "c9"    "da"    "ff"    "ff"
    "65"    "1e"    "00"    "00"
    "14"    "dc"    "ff"    "ff"
    "e8"    "29"    "00"    "00"
    "c9"    "cb"    "ff"    "ff"
    "29"    "1b"    "00"    "00"
    "32"    "ef"    "ff"    "ff"
    "80"    "f8"    "ff"    "ff"
    "b0"    "ec"    "ff"    "ff"
    "29"    "23"    "00"    "00"
    "09"    "cf"    "ff"    "ff"];
double(typecast(uint32(hex2dec(join(rawdata(:,4:-1:1),""))),'uint32')) * Gyro_const
ans = 20×1
1.0e+00 *

             0.01362196878
          4660.32657445404
             0.00543294549
           4660.3263335685
             0.00744683541
          4660.33669490193
           4660.3392242001
           4660.3344715935
             0.00752496045
          4660.32982640883