SID project #2

[NeurDis]

Well my first SID is done and out of the way so it's time to start the second, which of course brings up some questions.  ;)

I basically want to make a SID that consists of two parts. One part would have the Core, SID, LCD, and up/down buttons for changing patches. The second part would be a detachable control surface that connects to the first part with a serial cable (or whatever cable is conveinent). The idea is that when i want to edit patches I can connect the CS via the cable. Whe I'm not using the CS I can just unplug it and set it aside.

The two questions that this bring up for me are:

1) would it cause a problem for the SID/Core to have the CS there sometimes, and then not there other times. Would the core "miss" the CS if it wasn't there?

2) Is there a way to connect up/down buttons for scrolling through patches directly to the core without a DIN module?

Thanks in advance for your help!

[Wilba]

1) No and no. If you look at the DIN and DOUT schematics, each shift register is connected to the previous one with the same connections as the Core->DIN and Core->DOUT connections. Also, the DIN and DOUT modules share the same SCLK and RCLK lines, so your detatchable control surface only needs six lines (+5v, GND, SCLK, RCLK, SI, SO). Now, for example, if you put a DINx1 and DOUTx1 in your "first" part, and connect the other DIN/DOUT modules at the end of the chain, the whole lot will work whether connected or not. Pay attention to the 10k pullups R33,R34,R35,R36 on the DIN module... these keep the input high if the next shift register isn't connected... there's a similar one on the Core. The DOUT doesn't need anything like that, as if nothing else is connected the bits get shifted into the air  ;D

Now I just thought of something, should you want to detect whether the "extra CS" is connected or not, reserve one DIN pin for this, picture it as a switch that's always pressed down... when the extra CS is not connected, that switch will be read as open, when connected, it will be read as closed. You might want to make use of that, so if you disconnect the extra CS, you aren't stuck in some menu, it will jump back to the main menu where your up/down buttons work ;D

2) Yes, you can probably use pins on J5, although it would be better if you used just one DIN module (just a single 74HC165) as this would give you the option of more buttons if you need them, or attaching a rotary encoder (preferable for changing patches to up/down buttons), and no special coding required. I would also suggest you try to put more buttons on the part with the LCD... especially if you're considering running MB-SID V2, where you may also need to switch the synth engine (Lead, Bassline, Drums, Multi) and the BankStick.

[NeurDis]

Wow, thanks for the excellent answer. I'm still sorta learing all of this stuff as I go along. :)

My main interest is in keeping the actual core/sid unit as small as possible so it's easy to take to practice. I hadn't really taken v2 into account though, so I think I'll take your suggestion and put a step A CS on the main unit. I like your idea for preventing the unit from getting stuck in a sub-menu. I think I'll implement that as well if I don't have a menu button on the main unit.

Thanks again for the input. I'm sure I'll be back with more weird questions soon. ;D