LucaToni wrote:Questions RE: Db9_gpio_rpi
- In what cases would extra hardware be required specifically?
I'm referring to those controllers which have ICs that do not operate correctly with 3.3V. Most C64/Amiga-age joysticks are purely switch-based and work like a charm. The MD/Saturn controllers I've tested were fine with 3.3V, but there may be some exceptions.
LucaToni wrote:- Raspberry Pi B+ has 40 GPIO pins (instead of 26), does that mean more controllers can be used simultaneously, say 4?
Yeah, but the driver needs to be updated for that.
LucaToni wrote:- Are 3rd party 6-button Mega Drive pads included or is it just original brand ones?
I've only tested an original 6-btn MD controller, and based on the earlier posts there's apparently issues with 3rd-party ones.
LucaToni wrote:- How do I tell if my joystick is TTL, RTL, DTL, etc.?
-- For example, SpeedPad by Logic3 (6-button Sega Mega Drive pad with a mode button and a turbo switch too).
You'd need to open the controller and check the details of the IC(s) inside it. Probably just easier to test if it works or not.
LucaToni wrote:- SN74LVC245AN by Texas Instruments is probably the most easily and cheapest available. However on the first page of its datasheet it says:...
- Just like many other instructions by manufacturers/distributors/tutorials for use of a level shifter, use in conjunction with a pull-up resister is stated. But of how many ohms?
You don't necessarily need to worry about powerup/down behavior, but 10Kohm is a suitable value for a generic pullup resistor.
- Can this image and table be updated for B+ model, please? Or are there no changes, even if 4 controllers (if possible) were to be added?
I'll check if the pins are the same, and update the table if necessary.
- Do the +2 buttons in ID 6 refer to the Start and Mode buttons and does having a turbo switch make any difference here in terms of compatibility?
They refer to Start and Mode. I don't see a reason why a turbo switch would break compatibility.
[*]There also other questions like: 'Is it one level shifter (and resister) per controller?', 'Is additional power supply needed?', 'Where can I find a detail tutorial/schematic - a bit like what mahjongg posted above - for connecting DB9 (Sega Mega Drive) controllers, but that is a bit more clear/thorough/noob-proof?'
- which if would be answered would help immeasurably.[/list]
I'll see if I can add some extra information to the wiki to clear out the connections in different scenarios.