Joymega adapter on small PCB/connector (any interest?)

Prophet (2135)

30-04-2014, 16:01

Megadrive never had a select button.

The first version was the 3 buttons controller (which has 4 buttons, ABC+start)

The second joypad that was created later in the megadrive's lifecycle specifically for games like streetfighter, mortal kombat etc, the 6 button controller,(which has 8 buttons, ABCYXZ+Start+mode).

The mode button was generally used to select 3 or 6 button mode (need to hold it at boot, some games dont work in 6 button mode), but I dont know the technical details behind it since some games can also use it as a normal functioning button.

Those without the mode are most likely not official sega ones, but I just assumed the would function like the official 6 button one minus the mode

I still have to test my joymega thingy, I have a official sega 6 button that I can try (need to find it first, I have no clue were i put it ) , + i will order some of those knockoffs from deal extreme later on to compare.

Par Daemos

Prophet (2170)

30-04-2014, 16:59

The knockoffs are confirmed to work. I just soldered in the transistor into a knock off without the mode button and all buttons are recognized properly by the joymega utility. In R800 mode however only AB and C + start are properly recognized so I bet some slowdowns need to be in place when reading XY and Z

Par Daemos

Prophet (2170)

30-04-2014, 22:41

I have been thinking about the R800 problem and I think that the solution is to use a transistor that can give a even faster rise and fall time. The BC547B and (the used myself) BC548C have a rise and fall time of about 30-40 uS. If a faster transistor could be utilized it may solve the problems for a turboR in R800 mode.

This is pure speculation so there should be questionmarks everywhere. Opinion of the HW specialists would be appreciated to verify/unverify my claim.

Par sd_snatcher

Prophet (3677)

02-05-2014, 22:45

Does the R800 issue with this adapter also happen with the latest JOYTEST.COM utility? (not the old JOYMEGA.COM)

Par roadfighter

Champion (467)

03-05-2014, 10:54

sd_snatcher wrote:

Does the R800 issue with this adapter also happen with the latest JOYTEST.COM utility? (not the old JOYMEGA.COM)

Can't test it, just sold my last adapter to Syn

Par syn

Prophet (2135)

23-05-2014, 18:31

I recieved the one by roadfighter a while ago but due to various reasons (time+I was ill for a while+the adapter didnt fit in the joystickport directly due to it being a bit deeper), I only got to test it yesterday, and in existing msx games it works great

Today I did some more testing, like yesterday, with Joystick test v2.00

the joystick is detected as megadrive 6 button at first, but once I hold B or C, the detected type turns to megadrive 3 button. This causes me unable to do combinations with B and C with X,Y,Z and MODE, since those buttons will plainly stop working because those are just not available in 3button mode. Once I release the B or C button, the joypad switches back into 6 button mode.

Anyone else with joymega adapters from any make (either from roadfighter, homemade ones, those recently sold in brazil, directly modded in the joypads etc etc) have these same problems? Is it a bug in the test software or?

(test is done using a japanese version of the official 6 button megadrive joypad from Sega)

Par l_oliveira

Hero (534)

23-05-2014, 20:00

The SEGA six button controller works under a fixed and (somewhat rigid) timing chart. It's designed to fall back to 3 button mode if the timing is not correct for 6 button specifications (so 3 button games are compatible with it) and that timing is defined with a R/C circuit inside of the chip.

Toggling the mode pin (the pin we put a inverter in) causes it to charge the capacitor and the capacitor discharge rate is what controls the timeout.

Par syn

Prophet (2135)

23-05-2014, 20:43

So you are saying this is a problem with the test software from FRS?

im referring to this one: http://frs.badcoffee.info/tools.html

Par l_oliveira

Hero (534)

23-05-2014, 21:56

Must be that turbo knocks the timing out.

I need to find my adapter and give it a try, too.

Par syn

Prophet (2135)

23-05-2014, 22:24

i have a msx2+ on stock speed, but yeah this may be daemos' problem