This page explains how to convert a TurboGrafx-16/PC-Engine controller to USB. The firmware and most of the hardware design are shared with other projects, such as the Atari/SMS/Genesis joystick/controller/multi-tap to USB adapter and SNES/NES gamepad (and mouse) to USB adapter. The shared firmware supports TG16 controllers since version 1.7.

Features:

• Supports Pads with DIN and Mini-DIN connectors
• Two speed "Turbo" modes are functional
• No special drivers required. Implements a standard USB HID device

Adapter construction example using the surface mount circuit and an inline DIN connector:

Here is the schematic and some connector pictures (DINs on the left, MINI-DINs on the right) to help with the pinout:

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Component list:

Ref	Description
U2	Atmega8 microcontroller. ATMEGA8-16PC, ATMEGA8-16PI, ATMEGA8-16PJ or ATMEGA8-16PU. Don't use an ATMEGA8L-*, the 12Mhz clock would be too high.
R1	1.5k resistor. Ordinary carbon film 1/4 watt resistors will do.
R2, R3	68 ohm resistors. Ordinary carbon film 1/4 watt resistors will do.
D2, D3	3.6 volts zener diodes.
Y1	12 Mhz crystal.
C2, C3	18 pf capacitors. If the crystal datasheet recommends another value, use it instead.
C1	1uf capacitor. Install it near the ATmega8 power pins.
J2	6 pin header, 2.54mm spacing. Needed for programming the ATmega8.

For the USB connection, just strip the USB cable and solder the wires directly to the board. USB uses standard wire colors:

	Color	Description
	Red	+5 volts
	Black	Ground
	Green	D+
	White	D-

A microcontroller is a component which must be programmed in order to do something useful. So here is the hexfile which must be uploaded to the microcontroller:

File	Comments
nes_snes_db9_usb-1.9.hex	Special features added to support the Famicom controller with microphone. Wire the 'jumpers' in NES mode and short PC0 and PC1 together to use this new mode. Wire the extra input (PC2) for the microphone digital signal from the controller. 3 button mappings implemented for the abovementionned Famicon mode. Fixed the device name. (It would be corrupted or would not appear since the last few releases)
nes_snes_db9_usb-1.8.hex	TGFX has its own device name and VID/PID. Added Sega Paddle support (HPD-200). Auto-detected in DB9 mode. If the circuit is installed inside the controller, the two buttons can be wired independently. Controller polling synchronized with USB polls. Helps maintain an accurate timing when polling the controllers.
nes_snes_db9_usb-1.7.hex	Improved Genesis 6 button auto-detection Mode button now usable on Genesis 6 button controllers Sega multi-tap support (tested with MK-1654 only!)(technical info) Added TGFX controller support
nes_snes_db9_usb-1.6.hex	Changed the button IDs. Atari and SMS controllers were using button 2 and 3. Some emulators require button 1 so.... Added a way to force 6 Button mode for genesis controllers. Just in case your 6 button controller is not detected. Hold 'start' when connecting the USB cable to use this feature.
nes_snes_db9_usb-1.5.hex	Added support for Genesis 3 and 6 button controllers. All DB9 controllers (Genesis 3/6, SMS, Atari style 1 or 2 button and compatible) are auto-detected. The wiring is now different for DB9 controllers. Easier to wire to the multiuse PCB. NES controllers are now detected in SNES mode. This works great with original Nintendo controllers. If you have trouble with clones, use NES-only mode. The project is now released under the GPL v2 license
snes_nes_atari_usb-1.4.hex	Added support for Atari style joysticks (Atari, Commodore, etc). Two button variations (eg: Sega Master System) are also supported. Added padding to the nes report descriptor. This makes it work correctly on Windows. Linux sure is tolerant...
snes_nes_usb-1.3.hex	Fixed a bug which resulted in random button toggling when no controller was connected to the circuit. NES mode now has it's own USB product ID. PD1 is left in input (and no pull-up) since PD1 and PD0 must be shorted together in PCB rev.C (cleaner workaround than throwing away a batch of 50 PCBs and easier than cutting a track and soldering a wire...)
snes_nes_usb-1.2.hex	Added Snes mouse support.
snes_nes_usb-1.1.hex	Reworked the report descriptor for better behaviour under Windows and MacOS X
snes_nes_usb-1.0.hex	Initial release.

Many microcontrollers have what is called 'Fuse bytes'. In the case of the ATmega8, there are two bytes: The high byte, and the low byte. Those bytes are used to configure some aspects of the microcontroller. What type of clock to use? Crystal? Resonator? Internal RC clock? Allow programming via ISP? It's very important to set the fuses to the right values. Using the wrong values can render your MCU unusable.

For this project, here are the appropriate fuse values:
high byte = 0xc9, low byte = 0x9f

For details about how to program an AVR, visit my AVR programming page.

Pre-programmed Atmega8 (DIP package) available

For those who wish to modify the device behaviour or add support for new type of gamepads, here is the source code. Starting with version 1.5, it is released under the GPL v2 license. Previous version were released under the Objective Development license, which is basically GPL + extensions to cover hardware. See License.txt for more information.

File	Comments
nes_snes_db9_usb-1.9.tar.gz	Special features added to support the Famicom controller with microphone. Wire the 'jumpers' in NES mode and short PC0 and PC1 together to use this new mode. Wire the extra input (PC2) for the microphone digital signal from the controller. 3 button mappings implemented for the abovementionned Famicon mode. Fixed the device name. (It would be corrupted or would not appear since the last few releases)
nes_snes_db9_usb-1.8.tar.gz	TGFX has its own device name and VID/PID. Added Sega Paddle support (HPD-200). Auto-detected in DB9 mode. If the circuit is installed inside the controller, the two buttons can be wired independently. Controller polling synchronized with USB polls. Helps maintain an accurate timing when polling the controllers.
nes_snes_db9_usb-1.7.tar.gz	Improved Genesis 6 button auto-detection Mode button now usable on Genesis 6 button controllers Sega multi-tap support (tested with MK-1654 only!) (technical info) Added TGFX controller support
nes_snes_db9_usb-1.6.tar.gz	Changed the button IDs. Atari and SMS controllers were using button 2 and 3. Some emulators require button 1 so.... Added a way to force 6 Button mode for genesis controllers. Just in case your 6 button controller is not detected. Hold 'start' when connecting the USB cable to use this feature.
nes_snes_db9_usb-1.5.tar.gz	Added support for Genesis 3 and 6 button controllers. All DB9 controllers (Genesis 3/6, SMS, Atari style 1 or 2 button and compatible) are auto-detected. The wiring is now different for DB9 controllers. Easier to wire to the multiuse PCB. NES controllers are now detected in SNES mode. This works great with original Nintendo controllers. If you have trouble with clones, use NES-only mode. The project is now released under the GPL v2 license
nes_snes_usb-1.4.tar.gz	Added support for Atari style joysticks (Atari, Commodore, etc). Two button variations (eg: Sega master system) are also supported. Added padding to the nes report descriptor. This makes it work correctly on Windows. Linux sure is tolerant...
nes_snes_usb-1.3.tar.gz	Fixed a bug which resulted in random button toggling when no controller was connected to the circuit. NES mode now has it's own USB product ID. PD1 is left in input (and no pull-up) since PD1 and PD0 must be shorted together in PCB rev.C (cleaner workaround than throwing away a batch of 50 PCBs and easier than cutting a track and soldering a wire...)
nes_snes_usb-1.2.tar.gz	Added SNES mouse support.
nes_snes_usb-1.1.tar.gz	Reworked the report descriptor for better behaviour under Windows and MacOS X
nes_snes_usb-1.0.tar.gz	Initial release. Snes and Nes support.

Please contact me at raph@raphnet.net if you do useful changes.

Objective Development driver modifications:
The NES/SNES mode selection jumper changes the HID report descriptor. I had to modify Objective Development's usb driver to support this. Here is a diff against the usb driver from HIDKeys.2006-03-14:
usbdrv-diff

USB Vendor ID/Product ID pair:
Please do not re-use my VID/PID pair for derived or other projects. Instead, get your own. I bought my VID/PID pairs from mecanique, and they are much less expensive than the 2000$ US it cost to get a vendor ID from the usb implementers forum.

The surface-mount version uses my Multiuse PCB2 circuit. Here's what it looks like:

Multiuse PCB2:

Ready to use circuits available

I cannot be held responsible for any damages that could occur to you or your equipment while following the procedures present on this page. Also, I GIVE ABSOLUTELY NO WARRANTY on the correctness and usability of the informations on this page. Please note, however, that the procedures above have worked in my case without any damages or problems.

Now you cannot say that I did not warn you :)