Game Boy KR260

This project aims to port the VerilogBoy Game Boy emulator (https://github.com/zephray/VerilogBoy) to the Xilinx KR260 FPGA. The VerilogBoy emulator allows you to play Game Boy games on FPGA hardware.

Project Setup

To recreate the project in Vivado, follow these steps:

1. Open Vivado and navigate to the "project" folder.
2. Launch Vivado and run the command "source project.tcl".

Compiling and Loading Bitstream

Once the project is compiled in Vivado, you can load the bitstream onto the KR260 FPGA by following these commands in XSCT (Xilinx Software Command-line Tool) in sequence:

1. Connect
2. targets -set -nocase -filter {name =~ "*PSU*"}
3. mwr 0xff5e0200 0x0100
4. rst -system

Then, via Vivado, click on "Program device".

Project Structure

The project directory has the following structure:

• project: contains the TCL project file for recreating the project.
• sources: contains the project sources.
• tools: contains scripts for converting a Game Boy ROM file to COE format for loading the ROM into the Cartridge IP.

Static load or real cartridge load

The project supports both static ROM load (adding the ROM file to the Cartridge IP, see the tutorial below) both real cartridge load. The cartridge load needs a original Game Boy cartridge and a custom adapter for the Raspberry PI pinout of the KR260 (see the constraint file). For switching the 2 load mode, simply comment or decomment the line 23 of the top.v file (that is a define for 2 different block of Verilog code).

Loading a New Cartridge statically

To load a new Game Boy cartridge statically, generate the COE file and load it via Vivado interface. Follow these steps:

1. Generate the COE file using the provided tools/scripts.
2. Extract the number of lines of the .hex file and set it on the "Cartridge" IP ROM size.
3. Load the COE file in Vivado.

VGA Output and Joystick Mapping

For VGA output, you can use a PMOD VGA adapter. We recommend using this PMOD VGA adapter by Digilent. Connect the PMOD VGA adapter to the PMOD 3-4 ports.

The audio output is mapped on PMOD 2 on pin 1 (left channel) and pin 2 (right channel).

To map the joystick pins, replace the constant IP [0:7] with the desired PMOD pins. The joystick mapping is the following:

• 0: A
• 1: B
• 2: SELECT
• 3: START
• 4: DX
• 5: SX
• 6: UP
• 7: DOWN

When the signal is high, a button will trigger an event. If you implement your joystick in pull-up configuration, remember to invert the signal (with a Utility Vector Logic IP for example)

License

This project is licensed under the MIT License.

Please refer to the LICENSE file for more details.

References

VerilogBoy : https://github.com/zephray/VerilogBoy

Tobu Tobu Girl DX, an open-source game for GBC : https://github.com/SimonLarsen/tobutobugirl-dx