I have a few questions but my main one is: is there any disadvantage in using a board from an old xbox360 controller instead of an IPAC-2 board, for instance?
Since I want to use joystick with the 8 directions enable, I don't think the IPAC-2 would suffice either.
Bienvenidos a BYOAC, Ricardo.
The 8 directions come from only 4 switches.
Up, Up+Right, Right, Right+Down, Down, Down+Left, Left, Left+Up.
Either an IPac or hacked gamepad will work.
The only thing that might make the gamepad hack tricky is that some have 2 different grounds. There are several threads that talk about that.
The advantage of the IPac is that you don't need to solder.
The advantage of the gamepad is the lower expense.
There are several other lower-cost encoders that you might consider.
Vigo has the
ZD ReMatch if you want a gamepad-type encoder.
Degenatron's AVR Encoder is a keyboard-type encoder.
Depending on the software you want to run, there are advantages to both.
Scott