I had to convert an Atari Jaguar controller to USB for a customer. As usual, I decided to make the schematic and firmware for this project available to everyone.

Specifications:

• No drivers required. Implements a standard USB HID device.
• Tested under Windows and Linux.
• All 17 buttons are usable.

Button mapping:

Controller Button	PC Button
A	1
B	2
C	3
Option	4
Pause	5
1	6
2	7
3	8
4	9
5	10
6	11
7	12
8	13
9	14
*	15
0	16
#	17

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Jaguar controller with surface mount circuit installed inside:

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I used my usual Atmega8 circuit with a custom firmware using the Objective Development AVR-USB device implementation.

Here is the core schematic. For wiring the controller, use the table below.

I/O Micro.	#pin HD15	Couleur	Description
PC5	1	Brown	Column [N/A,opt,3,6,9,#]
PC4	2	Red	Column [N/A,C,2,5,8,0]
PC3	3	Orange	Column [N/A,B,1,4,7,*]
PC2	4	Yellow	Column [Pause,A,East,West,South,North]
PC1	6	Blue	Row [Pause,N/A,N/A,N/A]
PC0	10	Black	Row [A,B,C,opt]
PB5	11	Grey	Row [East,1,2,3]
PB4	12	Pale Blue	Row [West,4,5,6]
PB3	13	Pink	Row [South,7,8,9]
PB0	14	White	Row [North,*,0,#]
VCC	7	Green	Power
GND	9	Purple	Power

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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, but beware of cheap cables using non-standard color codes.

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

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A microcontroller is a component which must be programmed in order to do something useful. So here is the hexfile which must be flashed into the microcontroller:
jaguar_usb-1.0.hex

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

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The source code is released under the GPL license and compiles with avr-gcc. To prevent conflicts, please do not distribute modified version where the USB report descriptor has been modified without replacing the USB Vendor ID and Product ID by yours.

jaguar_usb-1.0.tar.gz

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

Multiuse PCB2:

Ready to use circuits available

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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 :)

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