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Finding the feedback terms of an LFSR
The aim of this task is to find the proper feedback function of an LFSR within a remote control emitter. This value is the second key to opening the safe.
A system comprising an RF emitter and a receiver allows to transmit a button press. When the emitter is powered via USB, it continuously sends the output bit of a 4-bit Galois LFSR. The receiver is connected to an FPGA board and a LED is switched on when the proper code is received.
The position of the LFSR XOR feed-in taps has to be found in order to match to the receiver. The LFSR polynomial is considered as a 4-bit binary number, which is the value to find.
An USB stick holds the structure of the VHDL and Microsemi deisgn environment.