Error while calling function from another function

Hi guys,

I have implemented successfully those two functions in matlab:

this function returns an array of unsigned values:

function ByteConvertRxBuffer=ByteConvertRxBuffer(rx) %rx is a binary array values that I want to convert it by this function to Byte array values
    rx=num2str(rx);
    rx=rx(rx~=' ');
    rx=bin2dec(reshape(rx,8,[])')';
    ByteConvertRxBuffer=uint8([rx,zeros(1,35-length(rx))]);
end

the other function is returning if my input crc is ok or not:

function crcOK=CrcValidationCheck(RxBuffer) 
    checksum = uint16(0); %#ok<NASGU>
    CRC_INIT=0xFFFF;
    checksum = uint16(CRC_INIT);
    PacketIndex=0;
    i = 1;
    while i <= numel(RxBuffer)
        checksum = calcCRC(RxBuffer(i), checksum);
        i = i + 1;
    end
    PacketIndex = PacketIndex + 1; %#ok<NODEF>
    if (checksum == 0)
        disp(PacketIndex); %this is for displaying the packetNumber that Im currently dealing with...may get more than one packet
        crcOK = true; %#ok<NASGU> % your packet number PacketIndex is Valid
    else
        disp(PacketIndex);
        crcOK = false;%#ok<NASGU> % your packet number PacketIndex is Valid
    end
end

the other function that Im calling is:

function crcReg = calcCRC(crcData, crcReg)
    CRC16_POLY = 0x8005;
    for i = 0 : 7
        if bitxor( bitshift( bitand(crcReg, 0x8000), -8), ...
                bitand( crcData, 0x0080 ) )
            crcReg = bitxor( bitshift(crcReg, 1), CRC16_POLY );
        else
            crcReg = bitshift(crcReg, 1);
        end
        crcData = bitshift(crcData, 1);
    end

so I've more another function which it's

function Result=Result(buffer)
rx=ByteConvertRxBuffer(buffer); %rx implicitly is valued as unsigned integers of array that's retunred from ByteConvertRxBuffer
Result= CrcValidationCheck(rx);

so I called the function Result in my command window in matlab and I get this:

it shows me this errors:

Error using bitand

Inputs must be signed or unsigned integers of the same class or scalar doubles.

Error in calcCRC (line 5)

bitand( crcData, 0x0080 ) )

Error in CrcValidationCheck (line 8)

checksum = calcCRC(RxBuffer(i), checksum);

First three functions are working seperately fine, this means if I tried to input to one of the first three functions any input it works fine !

but while I call those two functions from another function it doesn't work and I get errors !

Any help please how can I fix those errors? really weird how my functions seperately works fine but once I call to them between eachother they don't work properly.

In order to catch the bug I tried to make the code row in the function CrcValidationCheck

checksum = calcCRC(RxBuffer(i), checksum); as a note by "%"

and all code functions work fine, so the bug maybe while calling calcCRC function? if so how do I fix it?!

thanks alot

Answer 1

[Steven Lord]

What is your crcData? I suspect it is either a double array that is not a scalar or an array of an integer type that is not uint16. Convert the data to uint16 using cast or typecast before calling bitand on it with a uint16 as the second input.

[Jimmy cho]

crcData is one of every value of the Byte array values that Im getting from function ByteConvertRxBuffer !

in other words crcData is a value of uint8 !

the function ByteConvertRxBuffer returns array of uint8 values ! and I run by a loop on every value of those values calling function crcCalc at every value (see function CrcValidationCheck(RxBuffer) )

my crcData is a uint8 data, and it's a value of each array values of uint8 values called rx (the output of ByteConvertRxBuffer(buffer));

thanks