2 SID specific MIOS questions

[sizone]

Hi,

 

After an unsuccesful build attempt in 2006, I'm now an LCD upgrade and a couple of hours of grinding and screwing away from completing my Midibox sid. So, before I begin with my possibly pathetic questions about how to alter the code, I guess a quick thanks are in order for Thorsten and Tim.

 

So here are my questions

 

1: Besides the general compiling tutorial, is there a tutorial kicking around somewhere detailing how to change the key assignment for a DIN module? I'm going to be using a 2x40 LCD because it fits the case better and is easier to parse, but I was a humanities major and not an engineering major. While the mechanical and electronic side doesn't give me too much trouble, code kind of makes my head spin and it's been years since I've had to put together a tool chain or use an IDE or, you know, pretty much anything related. Any help to make this simple for me would be greatly appreciated. Specifically, I need to add in the 5 extra menu buttons and map them to the appropriate pins on the DIN.

 

2: This is the much more difficult and, ultimately, more important question: Is it possible to alter the OS to support micro and macro tonal scales? Neat as it is, if I'm stuck with 12 tone equal tempered, my SID friend is probably not going to get a lot of use. Ideally I'd like to be able to dump either .tun or midi tuning standard format tunings to the thing, be able to store them on a bank stick and assign them in patch. "Hard coding" a single tuning as part of the mbsid program would be, I'm sure, a lot simpler and also, I guess, pretty acceptable. Sadly, man, I don't have the slightest idea of how to even begin doing this. Again, any help would be appreciated.

[TK.]

Hi,

 

to 1) after installation of the toolchain you've to open the setup_*.asm file that you are planning to use. You don't need an IDE for this, the "wordpad" is suitable for editing as well.

Search for CS_MENU_DISPLAYED_ITEMS, set it to 10

Search for CS_MENU_DIN_TABLE, adapt the DIN pin assignments

Recompile the source code with "make"

 

to 2) see also this thread:  where you can read the details.

 

It's possible to adapt the frequency table, but there is no way to load it from BankStick, since there isn't enough RAM available.

Also flash memory is limited (meanwhile), there isn't enough memory free to store multiple tables in flash and to make them selectable from the patch.

 

Best Regards, Thorsten.

[sizone]

Thanks TK!

 

That certainly made setting up the buttons painless.

 

I'm still lost as far as the retuning goes, but I'll probably be able to figure it out eventually. I found the frequency table in the SRC directory, ..... ..... .....

Is there any way to change the octave size (ie, from 12 values to an arbitrary number), what's the relation between frequency and the hex values and how do I include an altered copy of the table into the build?

 

And what kind of beer do you like :) I'm not buying you any lambic.

[TK.]

The relationship is explained in the SID datasheet: http://www.waitingforfriday.com/index.php/Commodore_SID_6581_Datasheet
Search for "Equal-Termpered Musical Scale Values"
 
Since the frequency table is in the "critical timing path" of the synth engine, it's a flat table without comfortable octave transpose or similar.
Another reason for this approach is, that it's re-used for other functions as well (e.g. Curve, Keytracking, etc...)
 
Beer: Tegernseer http://beeradvocate.com/beer/profile/1796/6575
 ;-)
 
Best Regards, Thorsten.

[sizone]

Thanks again. If I ever get some time off, that should be enough info to figure out a retuning scheme. Is the table reused for any fucntions that would be bugged up by retuning? Keytracking, for example, shouldn't be a problem.

What's your paypal? I owe you a six pack, but it's got to be a strong stout or a doppelbock or something, these light lagers aren't going to fly.