DescriptionQ400
Q400DesignDVAppleASIC interview problem
Binary-to-Gray converter
TechniquesDesignDVGray codeAsync FIFO
DifficultyEasy
TopicClock Domain Crossing
LanguageSystemVerilog
Requirements4 checkpoints
01
Problem
Write combinational SystemVerilog that converts an 8-bit binary value to reflected Gray code and reconstructs the original binary value.
Module declarationSystemVerilog
module gray8 (
input logic [7:0] bin,
output logic [7:0] gray,
output logic [7:0] bin_back
);Example input and output
Use this case to check your interpretationInput
bin=8'd7Output
gray=8'd4, bin_back=8'd7Explanation
Binary 0000_0111 converts to Gray 0000_0100 and the prefix XOR reconstructs the input.
02
Requirements (4)
- Use gray = bin ^ (bin >> 1) for forward conversion.
- Copy the Gray MSB and prefix-XOR downward for reverse conversion.
- Keep both conversions purely combinational.
- Bound the reverse loop with a signed int index to avoid unsigned underflow.