This small PCB, which I named Multiuse tiny1 was originally designed to convert
NES/SNES controllers to USB. Since
there is not a lot of space availabe inside an SNES controller, I designed the PCB to be as
small as necessary. The PCB has improved since the beginning, thanks to the many other uses
I found for this PCB.
Small: width=27.5mm, height=17.7mm, thickness=3.4mm (withou regulator) or 5.3mm (with regulator)
Atmel AVR Atmega8 microcontroller on-board.
The following microcontroller signals are available via solder pads: PC5(ADC5/SCL), PC4(ADC4/SDA), PC3(ADC3), PC2(ADC2),
PC1(ADC1), PC0(ADC0), PB5(SCK), PB4(MISO), PB3(MOSI), PB2(SS/OC1B), PB1(OC1A), PB0(ICP1), PD0(RXD), PD1(TXD), PD2(INT0). Please
note that PD0(RXD) and PD1(TXD) are tied together.
Optional voltage regulator can supply a lower voltage to the MCU and/or external peripherals.
This circuit is perfect for the
Firmware-Only USB Driver from
Objective development. All necessary components are there (Atmega8, 12mhz crystal with capacitors,
68 ohms resistors and zener diodes).
To program the microcontroller, programmer wires must be soldered directly on the board. Just
follow the schematic. Some programming signals (unfortunately not all) are available on the
back side of the board.
When USB is not used, it is not necessary to solder the zener diodes nor is it necessary to install resistor R1. The 68 ohms
resistors R2 and R3 may be replaced by 0 ohm resistors if you need to use those ports. (That's what I
did for the
SNES/NES Gamepad to Gamecube/Wii adapter project.
The PCB backside has a footprint for an lm1117 voltage regulator. 0 ohm
resistors or solder bridges must be installed to select the power source
for the microcontroller and the circuit output.
When no regulator is needed, installing U3, R9, R10, C5, R7 and R8 is not necessary. But dont
forget to install R6, R6 and C1.
The voltage regulator has an adjustable output. Here is a convenient tool you can use to calculate the
output voltage that would be obtained depending on the selected resistors.
Here are composite images of the PCB top and bottom sides:
Option 'with regulator':
The regulator used is an lm1117mp-adj. 0 ohm resistors must be installed in order
to select the power source (Input voltage or regulator output voltage) of the microcontroller
and the board power output. For example, to supply 5 volts (from USB) to the microcontroller
and 3.3 volts (regulator output) to a game controller, resistors R5 and R8 would have to
Option 'No regulator':
When no voltage regulator is required, the only components
that must be installed on the bottom side are two 0 ohm
resistors. Install them according to the picture on the right. If
you dont have 0 ohm resistors, use short pieces of wire or do
a solder bridge.
Here is a wiring diagram for the PCB:
And finally, here are the gerber files which you may use to produce this
Due to the fact that this board is two-sided and has numerous vias, building it at home may
be a little harder than the ususal. If you want, you can get professional PCBs from
my online store. The PCBs from my store, however, are a
little older than the one above. I've had a huge quantity produced with a small mistake: The 5 volts
supply from the USB bus does not reach the regulator! In order to correct this, a small wire has to be installed on the bottom side:
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.