LogicLoom

A Minecraft mod for creating logic circuits and computers from Verilog designs.

Tutorial

Logic synthesis

Make sure you have installed Yosys. First write the desired logic in Verilog 2001. Then take the Synth.ys script from this repo and add read_verilog commands to the top of the file to read your design.

Run the script with

> yosys Synth.ys

The output JSON will be called mc_chip_maker.json load this file into MC using

>/logicloom load_json FILE_PATH

Limitations

Ports with Inout as direction are unsupported. The JSON file must only have one module. Only the first module is read all others are ignored.

Setup parameters

Maximum Iterations for the placement step

>/logicloom param max_iter NUMBER_HERE

Size of the placement area along X and Y axis

>/logicloom param chip_size NUMBER_HERE

Force initial force multiplier used during spreading cells during placement Should be a small value. Default is 0.05

>/logicloom param force_const NUMBER_HERE

Number by which to multiply the force multiplier every placement iteration Should be a small value. Default is 1.047

>/logicloom param force_mul NUMBER_HERE

When a straight wire between two point can't be run because of obstacles. A wave propagation algorithm is used. In order to sped up this algorithm a bounding box is constructed using the two points. The wave can go outside this box by a maximum of router_max_search. Default is 13

>/logicloom param router_max_search NUMBER_HERE

Path to the file made by Yosys

>/logicloom load_json FILE_PATH

Fixed points

Fixed points are like other cells, but they have a fixed position. They are used to move the design as needed. You will need to add at least one fixed point in order to get useful results. Currently, you can only add fixed points that are attached to every cell in the design.

All ports in a design are a fixed point attached to the cells they are connected to with weights of 1.

Position of fixed point is stored relative to the current starting point. If the starting point is changed after a fixed point is added the position of that fixed point in the world will change.

To modify fixed points use

>/logicloom fixed_points

P&R

Place the logic gates Make sure that the area is completely flat and on all ground blocks redstone wire and repeaters can be placed.

>/logicloom place

Place the Wires

>/logicloom route

Fixing bad wires

Currently, the wire placing algorithm has bugs so run this command can be used to check for broken wires This command compares starting point of all wires and checks if the power is the same at all ends. If not problematic ones are printed in the chat. If there are any issues they are usually obvious.

This command can find bad wires even if everything appears to behave correctly as those bad wires might not be currently affecting the output. You must wait for all signals to propagate otherwise you will get bad results. You can speed this up with /tick sprint

>/logicloom misc check_wires

To make sure all wire are checked you can use this command to force all wire to be

Powered

>/logicloom misc force_power_wire ON
Unpowered

>/logicloom misc force_power_wire OFF
Returned to the normal state

>/logicloom misc force_power_wire Normal

After running this command run the check_wires command.