PROPHET64 & MSSIAH Userforum

InactiveX · 2011-03-14 15:07:57

I've designed a new circuit for controlling MSSIAH using potentiometers.

This circuit features sub-miniature trim-pots for calibrating the range of the knobs' rotations. No longer are dead-zones a problem when using MSSIAH - this new circuit allows the full range of the pots to be utilised. The controls may be calibrated using MSSIAH's Diagnostics page, and once set, can be left alone.

I have also fixed the issue of pot tapering. This is the effect of the pots moving the on-screen pointers at different speeds, depending on how far the knobs are turned. This new circuit has a reverse logarithmic behaviour that approximates how MSSIAH operates closely.

Note that the circuit must be doubled to allow four pots to be used, with two pots on each of the Commodore 64 joystick ports.

I have constructed the circuit, twice, on a piece of stripboard measuring 2"x2". The mod may be housed inside a C64 along with case-mounted pots, or, as I have done, in an external controller box which connects to the joystick ports. All the parts are standard and can be obtained cheaply.

VR1 and VR2 are the main pots, while VR3 and VR4 are the respective trim-pots for calibration.

I would very much like MSSIAH users to try this out. If you decide to assemble this new improved circuit, please post your results here. Thanks.

luke-beataddicts · 2011-03-14 22:01:25

Hey mate, ordering parts soon. Looks great, hope it will work as good.

InactiveX · 2011-03-15 14:51:26

Great! Hope it works for you as well as it does for me.

One thing I forgot to mention: Flickering between values is much improved (although it can't be eliminated entirely due to the nature of how it all works).

For Maplin customers, here are the stock codes for the components:

VR1, VR2: FW06G

VR3, VR4: N43BR

R1, R2: M8K2

C1, C2: N06CN

DjFluorescent · 2011-03-16 02:54:42

This is definitely going in my 8580 machine. Thanks for trouble shooting this issue.. I've gotten used to the dead zones, but now there is no more need to put up with it.

Super job!

InactiveX · 2011-04-03 15:08:11

I've been having better results with calibrating the trim-pots using this program:

Code:

10 REM POT TESTING 
20 POKE 56333,127: REM TURN OFF KBD
30 POKE 56320,64: REM SWITCH POT#1
40 PRINT TAB(1)"X1:"PEEK(54297);
50 PRINT TAB(11)"Y1:"PEEK(54298);
60 POKE 56320,128: REM SWITCH POT#2
70 PRINT TAB(21)"X2:"PEEK(54297);
80 PRINT TAB(31)"Y2:"PEEK(54298)
90 POKE 56333,129: REM TURN ON KBD
100 GOTO 20

It gives a digital numeric readout, which offers more precision than MSSIAH's diagnostics page.

djaudiophile · 2011-04-07 06:57:13

Awesome. Now I have more mods to work on the Vicious Sid keytar I've never designed a production PCB but I have transferred ideas to protoboards. I think I'll try my hand at this one and revise my mod grip with it.

Good work man!

InactiveX · 2011-04-21 14:21:39

I've built two of the circuits now, and tried it on two different C64s. It all works great, and the trim pots hardly had to be moved when switching between computers.

Has anyone else tried it yet? I'd be particularly interested to hear from 6581 SID owners (I only have 8580 and 6582). It shouldn't make a difference, but as the SID is responsible for interpreting the pot signals, I'd like to know for sure.

InactiveX · 2011-05-24 19:45:06

Here's a photo (thanks to my photographer friend Andy!) of the board. The empty rows of holes in the foreground are for connecting to the joystick lines and the main pots.

Last edited by InactiveX (2011-05-24 19:57:18)

InactiveX · 2011-11-03 02:50:59

Works beautifully with my new 6581R4AR.

This controller will work for all SID types.

electriclifeform · 2012-02-12 23:33:30

just ordered my parts, going to build an external box with all the mods I can enclosed in it. thanks InactiveX

InactiveX · 2012-02-13 10:23:29

Good one. Let us know how it goes.

dJ dAb · 2012-02-15 00:19:28

Just out of curiousity... where should switches be installed on the above circuit, so as to disable pots and not interfere with 1351 mouse, paddle, etc. Pins 5 and 9?

Thanks, dAb

Last edited by dJ dAb (2012-02-15 00:21:32)

dJ dAb · 2012-02-15 09:43:06

Due to limited parts for my circuit I used a 100k linear pot, 8.2k resistor and 2 x 2200pf caps wired in parallel and it's pretty spot on.

InactiveX · 2012-02-15 09:56:47

dJ dAb wrote:
Just out of curiousity... where should switches be installed on the above circuit, so as to disable pots and not interfere with 1351 mouse, paddle, etc. Pins 5 and 9?

Thanks, dAb

No, if you place a switch to disconnect either pin 7 or 8, then that should do it.

InactiveX · 2012-02-15 18:06:08

Yes, that'll do you fine.

dJ dAb · 2012-02-15 18:18:51

Thanks. BTW... Getting a 64C today w/ 8580 sid. Have tons of older breadbins with 6581.

Now I can replace my faulty 8580 in my trusty 64C, I've had since 87...
http://www.youtube.com/watch?v=qUekZ3vd3Xo

electriclifeform · 2012-02-15 23:52:27

im currently struggling to relate the schematic to a stripboard pcb.... any suggestions or layouts?

electriclifeform · 2012-02-19 19:46:13

from which side of the joystick ports do the pin numbers correspond to? from the solder side of the plug side? which is pin 1 and does it count clockwise or counter-clockwise? sorry for all the questions!

InactiveX · 2012-02-19 19:55:35

Code:

    .---------------.
    \ 1  2  3  4  5 /
     \             /
      \ 6  7  8  9/
       '---------'

These are the pins, as facing the C-64's joystick sockets from the outside.

Last edited by InactiveX (2012-02-19 19:57:40)

electriclifeform · 2012-02-19 21:27:49

legend, thanks so much for the quick reply!

electriclifeform · 2012-02-19 22:26:10

brilliant, made up this circuit and just done the initial test using the mssiah ports diagnostic tool and it works brilliantly! my stripboard certainly not looking as smart but time to make the circuit again to enable to the 4 pots...thanks once again.

InactiveX · 2012-02-19 23:23:23

Nice one!

Don't worry about how tidy your board is. You only need good continuity and no shorts for it to work properly. You could even wire the components point-to-point, without any board!

InactiveX · 2012-02-19 23:27:15

dJ dAb wrote:
Due to limited parts for my circuit I used a 100k linear pot, 8.2k resistor and 2 x 2200pf caps wired in parallel and it's pretty spot on.

You have a certain lee-way with the values of the pots and caps. The important one to get right on is R1 and R2 (8k2). This affects the taper of the pots, and 8k2 is the ideal fit, regardless of what the other components are rated at.

The 100k pots are a little on the low side though. If you get some higher R ones that might be better (you may find that the trims' sweet spot is near the edge of the dial the way you have it now).

Last edited by InactiveX (2012-02-19 23:52:07)

electriclifeform · 2012-02-21 02:08:24

InactiveX wrote:
dJ dAb wrote:
Just out of curiousity... where should switches be installed on the above circuit, so as to disable pots and not interfere with 1351 mouse, paddle, etc. Pins 5 and 9?

Thanks, dAb
No, if you place a switch to disconnect either pin 7 or 8, then that should do it.

so a switch that can switch both controller 1 and 2 pins simultaneously? or do you only need to switch one of those pins on controller port 1?

thanks...

InactiveX · 2012-02-21 02:30:50

electriclifeform wrote:
InactiveX wrote:
dJ dAb wrote:
Just out of curiousity... where should switches be installed on the above circuit, so as to disable pots and not interfere with 1351 mouse, paddle, etc. Pins 5 and 9?

Thanks, dAb
No, if you place a switch to disconnect either pin 7 or 8, then that should do it.
so a switch that can switch both controller 1 and 2 pins simultaneously? or do you only need to switch one of those pins on controller port 1?

thanks...

A switch is only necessary if you have the pots mounted on the C-64 and wired internally.

The mouse is used in MSSIAH only with the Sequencer program. The mouse is plugged into controller port 2, and that is the one where you should install the switch.

PROPHET64 & MSSIAH Userforum

#1 2011-03-14 15:07:57

Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#2 2011-03-14 22:01:25

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#3 2011-03-15 14:51:26

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#4 2011-03-16 02:54:42

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#5 2011-04-03 15:08:11

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

Code:

#6 2011-04-07 06:57:13

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#7 2011-04-21 14:21:39

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#8 2011-05-24 19:45:06

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#9 2011-11-03 02:50:59

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#10 2012-02-12 23:33:30

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#11 2012-02-13 10:23:29

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#12 2012-02-15 00:19:28

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#13 2012-02-15 09:43:06

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#14 2012-02-15 09:56:47

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

dJ dAb wrote:

#15 2012-02-15 18:06:08

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#16 2012-02-15 18:18:51

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#17 2012-02-15 23:52:27

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#18 2012-02-19 19:46:13

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#19 2012-02-19 19:55:35

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

Code:

#20 2012-02-19 21:27:49

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#21 2012-02-19 22:26:10

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#22 2012-02-19 23:23:23

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

#23 2012-02-19 23:27:15

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

dJ dAb wrote:

#24 2012-02-21 02:08:24

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

InactiveX wrote:

dJ dAb wrote:

#25 2012-02-21 02:30:50

Re: Pot Controller - New Circuit, Uses Full Range, Taper Adjusted

electriclifeform wrote:

InactiveX wrote:

dJ dAb wrote:

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