Triple Modular Redundancy (TMR) in Verilog

This project demonstrates the implementation of Triple Modular Redundancy (TMR) using Verilog HDL, with two primary components:

1. Master Slave communication using the SPI protocol
2. Fault tolerant logic design via majority gate based TMR

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Project Functionality

Component	Description
SPI Communication	Implements synchronous master slave data transfer using the SPI protocol
TMR Logic	Introduces fault tolerant logic replication with a majority voter mechanism
Modular Verilog	Each subsystem is implemented as an isolated Verilog module
Testbench Verified	Includes testbenches to simulate and verify functionality

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Master-Slave Communication via SPI

Serial Peripheral Interface (SPI) is a full-duplex synchronous protocol often used in embedded systems for short distance communication.

SPI Line Description

Signal	Direction	Description
MISO	Slave → Master	Transfers data from slave to master
MOSI	Master → Slave	Transfers data from master to slave
SCLK	Master → Slave	Clock generated by master to sync data
SS	Master → Slave	Active low signal to select slave devices

SPI Role Definitions

Role	Responsibility
Master	Initiates and controls communication and provides clock and chip select
Slave	Responds to master’s commands and transmits or receives data accordingly

This implementation includes Verilog modules for both master and slave, handling bit-level data exchange over the SPI bus.

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Triple Modular Redundancy (TMR)

TMR is a hardware redundancy strategy where logic is triplicated and a majority voter is used to determine the final output. It is commonly used in critical systems to mitigate faults due to single event upsets (SEU) , hardware errors, or environmental noise.

Majority Voter Logic Table

Input A	Input B	Input C	Voter Output
0	0	0	0
0	0	1	0
0	1	0	0
0	1	1	1
1	0	0	0
1	0	1	1
1	1	0	1
1	1	1	1

Only one module failure (bit-flip or logic error) will not affect the final output, ensuring continued correct operation.

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Use Cases

Domain	Application
Aerospace	Fault tolerant avionics and control systems
Medical Devices	Reliable life supporting equipment
Industrial Control	Safety critical automation systems
Embedded Systems	Secure data processing units