Configuration

TMRX uses TOML format for configuration, passed to the tmrx pass with the -c flag:

tmrx -c tmrx_config.toml

If no configuration file is provided, TMRX uses built-in default settings.

Configuration Precedence

Configuration is resolved in layers, with later layers overriding earlier ones:

  1. Global defaults — built-in hardcoded defaults

  2. Global config — [global] section in TOML

  3. Group config — [group.<name>] sections

  4. Module config — [module.<name>] sections

  5. Verilog attributes — (* tmrx_* *) on modules

  6. Specific instance config — [specific_module."<name>"] sections (highest priority)

This layered approach allows you to set sensible defaults globally and override them for specific modules or instances.

Global Configuration

The [global] section sets default values for all modules:

[global]
tmr_mode = "LogicTMR"
tmr_voter = "Default"
preserve_module_ports = false
clock_port_names = ["clk_i", "clk"]
reset_port_names = ["rst_ni", "rst_n"]
expand_clock = false
expand_reset = false

[global.logic]
insert_voter_after_ff = true
insert_voter_before_ff = false
logic_path_1_suffix = "_a"
logic_path_2_suffix = "_b"
logic_path_3_suffix = "_c"

[global.full_module]
insert_voter_before_modules = false
insert_voter_after_modules = true

Module Groups

Groups allow you to apply the same configuration to multiple modules. Assign groups inline in each module scope:

[module.uart_rx]
groups = ["safety_critical"]

[module.uart_tx]
groups = ["safety_critical"]

[module.debug_controller]
groups = ["non_critical"]

Then define the group configurations:

[group.safety_critical]
tmr_mode = "FullModuleTMR"
preserve_module_ports = false

[group.safety_critical.full_module]
insert_voter_after_modules = true

[group.non_critical]
tmr_mode = "None"

Group names are scoped under group (for example, [group.safety_critical]).

Per-Module Configuration

Configure specific modules by name using the module scope:

[module.alu]
tmr_mode = "LogicTMR"
expand_reset = true

[module.alu.logic]
insert_voter_after_ff = true

[module.register_file]
tmr_mode = "FullModuleTMR"
preserve_module_ports = true

[module.register_file.full_module]
insert_voter_after_modules = true

Specific Instance Configuration

When using yosys-slang, parameterized modules are often uniquified with names like module$hierarchy.path. To configure a specific instance:

[specific_module."submodule$top.cpu.u_alu"]
tmr_mode = "FullModuleTMR"
preserve_module_ports = true

[specific_module."submodule$top.cpu.u_alu".full_module]
insert_voter_after_modules = true

Specific module configurations must include a $ in the name. Use this for uniquified module names from yosys-slang.

Verilog Attribute Configuration

You can configure TMR directly in your Verilog source using attributes:

(* tmrx_tmr_mode = "FullModuleTMR" *)
(* tmrx_preserve_module_ports = "1" *)
(* tmrx_insert_voter_after_ff = "1" *)
module critical_module (
    input  wire clk_i,
    input  wire rst_ni,
    input  wire [7:0] data_i,
    output wire [7:0] data_o
);
    // ...
endmodule
Table 1. Supported Module Attributes
Attribute Values Description

tmrx_tmr_mode

"None", "LogicTMR", "FullModuleTMR"

TMR strategy

tmrx_tmr_voter

"Default"

Voter type

tmrx_preserve_module_ports

"0", "1"

Keep original interface

tmrx_insert_voter_before_ff

"0", "1"

Voters before FFs (planned)

tmrx_insert_voter_after_ff

"0", "1"

Voters after FFs

tmrx_expand_clock

"0", "1"

Triplicate clock

tmrx_expand_rst

"0", "1"

Triplicate reset

tmrx_assign_to_group

"group_name" or "group1;group2"

Assign to group(s)

tmrx_clock_port_name

"clk" or "clk1;clk2"

Clock port names

tmrx_rst_port_name

"rst" or "rst1;rst2"

Reset port names

For list values in attributes, use semicolon (;) as separator.