Confused by an expansion port

[Syntax]

Hi all,

I want to use the full potential of my MB6582 and therefore exploring the possiblilities of the expansion port. I read some posts and manuals on this subject, but still dazzles a little. Some statements and questions below...

1) Using Analog (CV) inputs. Could I use a AIN module to extend the analog inputs (multiple them). Does this make sense in respect of the capabilities of the MB6582?. If so I have to connect to J5_Core and J6_Core. If not could I directly hook up to J5? (respecting the 0-5V input range of coarse :smile: )

2) Using CV outputs. Do I need an AOUT module? and therefore hook up to J6_Core

3) As the MB has 4 cores does this mean I could have CV inputs and CV outputs four times? This will need a 50 wire cable for the expansion port (I'm thinking of a SCSI cable) hooking up to a breakout box with proper jacks/pots etc for all the fun. And finally is this thought meaningful?

I'm sure I missed some posts so some questions are probably answered elsewhere which I couldn't find browsing the website and forum all evening. So any help in this is highly appreciated.

[Shuriken]

1.) I think only CVOUT is supported. Why would you need CVIN?

2.) Yes you need an AOUT or AOUT_NG module.

Edited July 28, 2010 by Shuriken

[Imp]

The info you need is in here, under "Analog Control Elements".

You can use 5 inputs per pic, no multiplexing.

I think this extension only makes sense in combination with some analog gear.

Edit: Maybe Shuriken is right about 1),

I just thought, if the modular SID can handle CV inputs, the MB6582 should too, but maybe it doesn't...

Edited July 28, 2010 by Imp

[seppoman]

I just thought, if the modular SID can handle CV inputs, the MB6582 should too, but maybe it doesn't...

well that depends how you understand "can handle CV inputs".

btw, the MB6582 is in no way different featurewise to the "modular SID", it's just all the necessary modules in one neat and convenient package, and it has all the connectors you'd also have with a modular MBSID.

The thing is, MBSID provides 5 pot inputs that can be routed via the KNOBs menu, but these inputs have to be expanded a bit to accept standard V/Oct signals. As it is, it only accepts voltages between 0 and 5 Volts and it doesn't have any protection against overvoltage etc. So you need to add a little OpAmp based circuit to scale down the inputs to an acceptable voltage. This is no magic, but strictly speaking a regular (non-modified) MBSID/MB6582 can't handle CV inputs.

I don't know if someone already did these mods and uses CV inputs on a regular basis - I think it should be possible but you'll need to setup the KNOB parameters of all your patches where you want to use these inputs and I'm not sure if there is a way to trigger note on/off from these inputs, i.e. if you can have a Gate input.

And the other question is, does it really make sense to have CV inputs at all? I mean you've got all the LFOs, Envelopes and all internal routing possibilities you could ever imagine, i.e. using external EGs or LFOs doesn't make much sense in my opinion.

S

[Syntax]

The info you need is in here, under "Analog Control Elements".

I knew I had read it before somewhere!

Oke let's summerize

Analog (CV) Inputs

This feature has to be explicitely enabled within the setup_*.asm file by setting DEFAULT_J5_FUNCTION to 1 - once you did this, all unusued analog inputs must be clamped to ground in order to prevent random values! This is especially required for the slave modules, when the master firmware will be transfered to the slaves via ECAN (clone feature).

I assume when cloning the masterpic (0) this DEFAULT_J5_FUNCTION is also set for the PIC slaves 1, 2 and 3.

All 8 analog inputs are sampled with a frequency of 125 Hz. Multiplexing (-> MBHP_AIN module) is *not* supported! So, 8 inputs are maximum. The firmware currently only uses the first 5 inputs of J5, the remaining 3 are reserved for future features. The converted values are forwarded to the knob handler. This generic approach gives you all advantages of the knob concept: value changes can be forwarded to two sound parameters, a Min/Max range can be specified, and the converted values are also available as modulation source!

The thing is, MBSID provides 5 pot inputs that can be routed via the KNOBs menu, but these inputs have to be expanded a bit to accept standard V/Oct signals. As it is, it only accepts voltages between 0 and 5 Volts and it doesn't have any protection against overvoltage etc. So you need to add a little OpAmp based circuit to scale down the inputs to an acceptable voltage. This is no magic, but strictly speaking a regular (non-modified) MBSID/MB6582 can't handle CV inputs.

So the header J5 provides 5 analog inputs for each PIC? AIN is not supported, that's understood. Input range values are 0-5V, an additional circuit must level CV voltages to 0-5V, which is no rocket science :whistle: can do that

The feature behaves differently on master and slaves:

Master: analog inputs are forwarded to the *selected* SIDs. This has the advantage, that each SID can be controlled from a single set of pots and/or joysticks. If you find this impractical, a small and harmless firmware patch (AIN_NotifyChange: remove the branch to "AIN_NotifyChange_Master") allows you to realize a dedicated control for the master only.

Slave: analog inputs are only handled internally independent from the selection.

Note that this feature can also be used to control the SID from analog signal sources, e.g. from an analog step sequencer, or an analog LFO.

So default the system is setup with 'master behaviour'. How does this relate to the knobs menu for the slaves? And will disconneting the master result in 4 seperate' controllable PIC, hence each PIC will have it's own seperate analog input control? And is this called 'slave behaviour' or is this another feature?

b]Analog (CV) Outputs

1.) I think only CVOUT is supported. Why would you need CVIN?

2.) Yes you need an AOUT or AOUT_NG module.

Let's use an AOUT_NG module. This must be connected to header J6_Core. Which gives 8 channels of CV out. In the schematic referred to in the AOUT_NG description, two gates out are mentioned. What has happenend to them as I can't trace them in the NG module schematics? :wacko:

data connection to the core. The pin assignment is the same as on the AOUT module. For connection to MBSID, the blue lines on this link show the necessary connections.

In total 4 AOUT_NG modules could be connected, so 1 for each core?

Confused again

In the manual section CV option the following is described

In addition to the analog outputs, the firmware allows to control 8 digital outputs (e.g. switches, gates, triggers) as well. The state of the outputs is stored within the patch structure, so that the setup can be recalled. In addition, the outputs are accessible via control surface (-> EXT menu), NRPNs, Knobs, Wavetable sequencer, etc...

The outputs are either available at J5 of the core module (set DEFAULT_J5_FUNCTION to 3), and/or on a DOUT shiftregister (set ENABLE_AOUT to != 0, and set DEFAULT_EXT_SWITCH_DOUT to a value between 1 and 16).

Optionally, internal gate/slide and accent signals can be forwarded to the digital outputs as well, which gives you the possibility to trigger external synths the same way like the 2*3 SID oscillators (per core).

The outputs are available on header J5_Core. At first this was the analog input header. How does this match? Well apparently the J5 can do both I discovered. Are the digital output also limited to 5 like the analog inputs?

Why bother?

Well I just like experimenting with my modular and overheating my soldering iron :laugh: Therefore I would regret not utillizing the full potential of the MBSID.

A long story to tell but usefull for me to decide how to expand my MBSID and hopefully also for others. Any feedback on questions above is appreciated. Thx