Concise Explanation and Question
In verification, we build test environments to ensure that hardware will function correctly after production. One common testing tool is the PRBS (Pseudo Random Binary Sequence) mechanism, which generates a predetermined bit sequence that simulates real communication. This mechanism allows the receiver to verify the correctness of the received bits based on previous bits without needing additional information from the transmitter, thus saving valuable resources on the chip.

Question:

Design a digital circuit that implements the following formula with an initial value of 2:
X
new
=
X
[
7
]
⊕
X
[
6
]
X
new

=X[7]⊕X[6]
Next, design a test circuit that outputs two indications:
prbs_ok: An output that will be 1 when the next bit matches the expected one, and 0 otherwise.
Counter (counter): Increments by one each time an error in bit detection is identified.

Question

Concise Explanation and Question
In verification, we build test environments to ensure that hardware will function correctly after production. One common testing tool is the PRBS (Pseudo Random Binary Sequence) mechanism, which generates a predetermined bit sequence that simulates real communication. This mechanism allows the receiver to verify the correctness of the received bits based on previous bits without needing additional information from the transmitter, thus saving valuable resources on the chip.

Question:

Design a digital circuit that implements the following formula with an initial value of 2:
X
new
=
X
[
7
]
⊕
X
[
6
]
X 
new
​	
 =X[7]⊕X[6]
Next, design a test circuit that outputs two indications:
prbs_ok: An output that will be 1 when the next bit matches the expected one, and 0 otherwise.
Counter (counter): Increments by one each time an error in bit detection is identified.

Anonymous · Accepted Answer

The digital circuit can be implemented using a shift register of appropriate size, initialized with the value 2, where the calculation is based on the XOR operation of two previous bits.
The test circuit would include a comparison between the received and expected bits:
prbs_ok would be set to 1 when the bits match.
The counter would increment each time the bit does not match the expected one.

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