Configuring the Camera4-10 Basler A500k SeriesPRELIMINARY4.2.3.3 Calculating the Block Check CharacterThe block check character in any A500k command is the exclusive-or sum (XOR sum) of the bytesin the descriptor and the data fields. For the write command example shown in Section 4.2.3.2,the block check character is 0x45. Let’s consider at how this block check character wascalculated.In this case, we must find the XOR sum of three bytes. This is done by finding the XOR sum ofthe first two bytes and then by taking the result and finding the XOR sum of the result plus the thirdbyte.Calculating XOR sums is most easily understood when numbers are shown in their binary form,so in the example calculations shown below, the hexadecimal digits in our command have beenconverted to binary.To find the XOR sum of two binary numbers, you add the two digits in each column using thefollowing rules:If both digits are 0, the result is 0.If both digits are 1, the result is 0.If one of the digits is a 1 and the other is a 0, the result is 1.With all of this in mind, here is how the check digit for the write command shown in Section 4.2.3.2would be calculated:0 1 0 0 0 1 1 0 = the binary representation of 0x460 0 0 0 0 0 0 1 = the binary representation of 0x010 1 0 0 0 1 1 1 = the XOR sum of the first two bytes0 1 0 0 0 1 1 1 = The XOR sum of the first two bytes0 0 0 0 0 0 1 0 = the binary representation of 0x020 1 0 0 0 1 0 1 = The XOR sum0 1 0 0 0 1 0 1 = 0x45 = the block check character
