SID interconnection problems

[dcer10]

Hi,

I have been working on my sid synth and have hit a brick wall. It has:

1x core

1x sid with 8580 (v2)

1x 40x2 lcd

1x din

1x ltc

1x 8 x 256 chip memory modules on a board

3x encoders

18x buttons

I am re using the power supply from the C64, and have made the small power circut as shown:

http://www.ucapps.de/mbhp/mbhp_sid_c64_psu.pdf

I connected everything up as shown in the above pdf. When I power it all up, nothing. Using this diagram (without the sid connected) the core powers up and loads the sid interconnection application ok.

I disconnected the sid and tried to wire it up as shown in this diagram:

http://www.ucapps.de/mbhp/mbhp_sid_v2_core_interconnections.gif

But still nothing. I can connect up most of the wires and still have the core boot up, but the final few I connect seem to stop the core from booting up in both situations.

I am going to try to build the power up as shown in:

http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf

and try again, but it looks to me like something has gone wrong with the sid maybe? One constant I noticed was that in each case when connecting sid J2 vd to core J2 vd it would not start up.

Im really stuck with this. Can anyone help please?

Thanks in advance,

John

PS: The photo below does not show the problem I am describing. Since the photo the sid and core are joined as per the PDF’s mentioned above and the crystal is removed from the core and connected via J7 from the core. The connections on the back panel are (left to right) Memory switch (int 8 chips, off, or external) then midi in/out, a svideo connector for external banksticks, c64 power plug and on off switch. Also the top panel has now had 10 extra select buttons added above the screen for the menu navigation, and 2 buttons removed and replaced with encoders for cutoff freq and resonance (I read the resonance control is very weak, is it worth having an encoder on this? I will re assign it to something else like decay or LFO if anyone can comment on this).

[Altitude]

I disconnected the sid and tried to wire it up as shown in this diagram:

http://www.ucapps.de/mbhp/mbhp_sid_v2_core_interconnections.gif

Thats the wiring for the V3 board (i did the same thing)

Look here:

http://ucapps.de/mbhp_sid_old.html

The SIDs should be wired like in the GIF.  The 5V line should come directly off of the optimized PSU to J2. Dont forget to pull the 10 mHz off of the sid module and replace it with a jumper to the middle pin of J7 (middle pin of J7 is CLK from the core and can be connected to one of the legs where the 10 mHz clock was on the sid board, its pretty self explanintory once you look at it)

[dcer10]

Hiya,

Thanks for the suggestion, but after a long time of debugging it landed up being that one of the IC’s was upside down! I still have problems being that now it boots up, but after saying MIOS V1.9 the char lcd starts to randomly show non text characters and gradually corrupts itself almost completely. While this is happening the pic is spitting out a bunch of seemingly random midi events inc prog changes, sysex, and others… Also it seems that the pic (which worked fine up until now) can not be re programmed via midi any longer. I did have on it the SID interconnection application, which only showed Pin: A0 on the screen (along with the top row of text), is that normal for the test app or does it seem that I still have an interconnection problem?

Thanks,

John

[Altitude]

No. sounds like you have a midi problem (a loop maybe) you need to get the core working with or without the sid plugged into it. 

[Sebo]

About the random characters, it did happen to me after I try to upload another application

to the PIC, when MIOS was alredy booted up.

Try to upload the app (or even MIOS) in the first 2 seconds after power up, before

the MIOS ver 1.9 screen shows up.

Hope you solve it.

[T.K]

Such effect can happen when there is a problem with the MIDI connections to the PC, the PC MIDI Interface or the MIDI driver - e.g., I can reproduce this with a 10 m USB cable enhancement (out-of-spec) to a MIDIsport 2x2 interface - code uploads are not reliable in this case, and MIOS Studio shows errors - this is correct, problem is not MIOS or MIOS Studio here, but the unsteady transfers to the core.

So, did MIOS Studio report an error during the upload?

However, as Sebo has mentioned, you can revive the core by uploading the application via 1st level bootloader

(MIOS itself propably doesn’t need to be uploaded again)

Best Regards, Thorsten.

[dcer10]

Hiya,

Thanks all for your replies. Interestingly enough I was using a midisport 2x2 but not with a long cable or anything else which can cause midi problems. I checked over all the connections and they were ok. The only thing I could think of is that the last program upload happened from a G3 mac. It looked like it worked to begin  with, but obviously not. I could not re load it from the PC but I did put the pic into my midibox pic programmer and started over, it now works fine. Another side note is that I have tried the MIOS studio application with the midisport 2x2 on windows xp sp2 and it does not work in my case. I can upload normally with midiox (which I prefer anyway) but MIOS studio doesnt seem to see the midi ports.

In any case my SID synth is now functional! I am using the power solution shown on the site which re uses the C64 PSU, but not the one for 4 SIDs. I have noticed that there is quite a bit of noise on the output. Is it possible to reduce this somehow? The s/n ratio is not too bad, but there is a definate high pitched digital type noise in te background which seems to change depending on which patch program you are using. The ones with the filters seem to have more, and the filter seems to click when changed, is this normal?

Thanks everyone for their comments.

John

[Altitude]

but there is a definate high pitched digital type noise in te background which seems to change depending on which patch program you are using

Did you remember to add the 2200 uf/16V cap to the end of your power chain? I have the 4 sid running and it is super quiet so sounds like you did not add it. Also short the audio input (J4 on the sid)

[dcer10]

Hiya,

I did see this cap on the diagram on the 4x sid synth, wasnt sure if its needed on a single so missed it out. Do you know what pins to put it on? Also what do you mean by short the audio input on J4, do you mean to join the pins? I was hoping to use the line in for the filter, is this not possible or does it add too much noise?

Thanks again,

John