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pythonboolean-logicparity

Can the two paritiy bits in the LIN-Datatelegram guarantee that every error is caught in the Identifier Field?

The LIN-TElegram has a protected Identifier Fild with a Frame-ID consisting of 6 bit, followed up by 2 Bits that build the two Parity bits.

The first Parity Bit P0 gets calculated like this:

Bit0 XOR Bit1 XOR Bit2 XOR Bit4

The second Parity Bit P1 gets calculated like this:

Bit1 XOR Bit3 XOR Bit4 XOR Bit5

Is there an easy way to test this in Python / Matlab? Or a simple mathematical solution on how to know how many bit errors can be caught by this mechanism?

I do not know if this question really belongs on SO, but I could not find a more fitting stackexchange

Solution

  • No.

    For example for

    Bit0 XOR Bit1 XOR Bit2 XOR Bit4

    Bit1 XOR Bit3 XOR Bit4 XOR Bit5

    it is clear that swapping the values of bits 1 and 4 will yield the same results.

    Generally, parity bits only guarantee that exactly one bit error in the inputs will get caught, but if there are more, all bets are off.