I am new to the whole midi&soldering business and have recently built a simple “step a” sid (1 CORE + 1 SID + 1 LTC (passive) + 1 512k-BANKSTICK + OPTIMISED_C64_PSU).
I experience random midi glitches when playing the sid via keyboard or sequenting it from my computer, it seems that note off events go amiss and notes hang (they stop on midi reset or if I lay my hand on the keyboard and trigger lots of events at the same time). Also when sending patches via jsynthlib, data corruption can lead to “interesting noise” due to weirdly programmed patches.
When having the LTC module (without MAX) plugged in, the situation worsens to the point that I cannot upload MIOS anymore - I get a lot of “MIDI IN OVERRUN” (or something similiar) messages in MiosStudio.
I noticed, that in fact, each time a note hangs, the mbsid sends a midi message, that is, the midi out led lights up. What does this mean?
I started out using a PIC18F4620, but now use a PIC18F4685 with MIOS 1.9e. I’ve tried MidiBox SID 1.74685 and 1.7303b on both and the problem persists. In fact, when using the 1.74685 release, the box keeps on rebooting endlessly, but this may be another problem.
If you are 100% sure that the interface is OK with some other similar MIDI devices, I would strip it down to the minimal setup my removing the bankstick and LTC, and then do TK’s MIDI Troubleshooting. Good luck!
Unfortunately the LTC module cannot be used as MIDI replacement for MIDIbox SID.
It doesn’t surprise me that you will see MIDI timeouts, as the whole synth engine is optimized for “slower” MIDI transfers (baudrate 31250), whereas 38200 used for RS232 transfers is definitely too much.
I did the whole troubleshooting procedure before, and it seemed ok so far. But then I replaced the optocoupler because I was frustrated and I didn’t know what else to do . This improved the stability a lot - still without the LTC-module connected, which made the system unstable again. I found a second bug on the LTC - I just forgot to solder the capacitors on the bottom side.
Now everything just runs smoothly, great
@TK: I wish to use the LTC only for a MIDI-tru and blinking lights, not for connecting it to my pc.
I will now try to get MidiBox SID 1.74685 running and to connect a user interface.
No, the MAX232 ist not present - as I said, I just wanted blinking lights and a midi through port. ;D
@TK: You did a great job designing this plattform! I consider also using it to midifi a Roland Trident, but beforehand I’d like to earn some ucapps-xp and get my sid user interface to work.
. This improved the stability a lot - still without the LTC-module connected, which made the system unstable again. I found a second bug on the LTC - I just forgot to solder the capacitors on the bottom side.