blingy

Midibox SEQ V4L Din Sync

19 posts in this topic

My Midibox Seq V4L is complete and beautiful. It works brilliantly. Now I want to mess up it's MIDI beauty by adding din sync in order to sync it's insanity with certain Roland devices. If I'm reading MBSEQ_HW.V4L correctly with LPC17 as my core, by default it should output clock to J28.SDA and start/stop to J28.SC. If my understanding of din sync is correct (and this could be where things go awry), J28.SC should give me +5v as long as the pattern is playing. I don't have a scope handy so I'm trying to test this with a multimeter. I'm not getting any voltage on J28.SC or P2.11 on the Xpresso board even when the pattern is playing. Either I'm misunderstanding how din sync works or I'm missing a step here. I'm still waiting for a sd card in the mail so I'm working from the default configuration at the moment. Any insight would be helpful. Thanks!

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That makes sense...I guess I misinterpreted the documentation:

##################################################
# CV and Gate/Trigger/Sync Setup
##################################################

# AOUT interface now selected in CV Configuration Menu and stored in MBSEQ_GC.V4T file
# please scroll through the menu to find this page!

# should J5A/B/C outputs be enabled (0: no, 1: yes, 2: yes, but in open drain mode)?
#  - the 6 first AOUT gates will be forwarded to J5A/B
#  - the remaining last 2 AOUT gates are available at J5C.A10 and J5C.A11 (LPC17: J28.WS and J28.MCLK)
#  - DIN sync clock will be forwarded to J5C:A0 (LPC17: J28.SDA)
#  - DIN sync start/stop will be forwarded to J5C:A1 (LPC17: J28.SC)
#  - if open drain mode enabled (option 2), external pull-ups have to be connected to J5 pins
#    (advantage: pin levels can be pulled to 5V)
#
# NEVER USE THIS TOGETHER WITH ANALOG POTS - IT WILL CAUSE A SHORT CIRCUIT!

 

That said I still should be getting 3.3V on J28.SC, no?

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Yeah, you should see pulses, Dont think a meter will cut it though.  You'll need a scope.  This should work out of the box..  You can try a soundcard scope like this: http://www.zeitnitz.de/Christian/scope_en

Edited by Altitude

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I think the pulses would be on the clock pin, not the start/stop pin.

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yes, of course.  That's what I thought you were measuring.. IIRC, start/stop is a pulse as well though..

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No, the documentation is correct: with "J5_ENABLED 1" the clock pulse is available at J28.SDA, and the start/stop signal is available at J28.SC

 

Best Regards, Thorsten.

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Is there a setting somewhere for the PPQN? I have added a level shifter but it's still not running at the same tempo. Slowing down the tempo slows the instrument receiving the sync, but it's not quite lined up. More testing to be done tonight and I will post some pictures of my level shifter. Thanks.

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OK I don't think it's a PPQN setting, I think the voltage coming from IC6 isn't actually +5v on my build. So I'm only level shifting it up to about +4.7v and my 303 is quite picky about getting +5v on the clock pulses. Even when I power the midibox from a laptop it only gets up to about +4.9v. Any ideas? Maybe I just need to build a power adapter to get din sync out.

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Yes, an external PSU should help to get exactly 5V at the 7805 output.

 

Best Regards, Thorsten.

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hey i just soldered the level shift buffer circuit, but i am really an idiot when it comes to software.

 

can someone tell me what (and how) I have to do to get a Din sync signal?

 

 

I read through a couple of things but as i said i am really not into code things...

 

best max

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Open the Tools->MIOS32 File Browser in MIOS Studio, connect to your SD Card, upload the hwcfg/standard_v4l/MBSEQ_HW.V4L file.

 

It has already the right configuration to enable the DIN sync output (J5_ENABLED set to 1)

 

Best Regards, Thorsten.

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Hi blingy, have you managed to resolve your Din sync lagging issue? I seem to be having the same problem. I have level shifted the J10 clock output from my STM32 and I'm getting 4.99V on the start/stop signal (which works fine), but only around V0.20 on the clock signal. My MC202 does respond to changes in the tempo but it always lags behind a bit. I wonder if there is any way I could compensate for this lagging through the software.

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Ok, I think I've figured this out - After checking with another Din sync/MIDI converter it looks like it's not the clock being sent from the Midibox seq v4 that's wrong (and thus it's not a matter of voltage), but that the MC202 adds some extra time in the last step of every sequence. This makes it drift. I've worked out that the 202 sequences need to be trimmed a bit at the end to get the two to synch properly. 

 

I hope this helps anyone that comes accross the same issue

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Never did get din sync as tight as I'd like it to be, ended up just using a 707 as master.

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Never did get din sync as tight as I'd like it to be, ended up just using a 707 as master.

 

Ah the 707, the true master of many a setup and surely the greatest all round MIDI/sync/trig/converter, but with bonus drum sounds :smile:

I too had timing issues with din sync24 out to a 202/303. I think I've solved it, so I thought I'd share the joy. Besides which, I've been lurking for ages, so I hope this first contribution helps other MIDIboxers. Big thanks to Mr Klose (and others) for their tireless work - we are all essentially standing on the shoulders of giants.

 

I'm using a USB powered MBHP_CORE_LPC17 core running MIDIbox SEQ V4. I'm a long way from putting it into a case - just using bulldog clips/stripboard etc for now, though I have stuffed together 1x SD Card bodge, 2x 40x2 LCDs, 1x DIN and DOUT R5 boards, and some loose buttons to get up and running. Initially I hooked up the 303's Sync input to J28.SDA, as documented here: LPC17 connections.

 

To my surprise, my 303 responded, i.e. it did play, although the timing was all off. There was a noticeable but inconsistent lag between some steps every bar or two, making it practically unusable. It was as if the 303 was pausing momentarily on some steps. Sort of an interesting effect, but would clearly cause any dancefloor to react badly. Initially, I thought it probably needed a 3.3V -> 5V level shift with a 541, but that didn't seem make a difference. Time to get the scope out...

 

Here's the din sync clock output from my MC202. 5ms/dev horizontal, 1V/div vertical (though I don't trust my scope's calibration - the poor thing is nearly as old as me).

post-20226-0-13059900-1433412226_thumb.j

 

Compare this with the output straight from J28.SDA. You can see it's 3.3V as expected, but the default pulsewidth (1ms?) looks too short.

post-20226-0-43871900-1433412253_thumb.j

 

Stuffing this signal through a 541 and tweaking the pulsewidth, I found that 8ms was spot on with the defaults set for clock divider=16 and 24 PPQN. Now we have 5V pulses/square wave (I actually measured the supply at 4.84V with a meter on the 541) and a pic very similar to the first. More importantly, both the 202 & 303 behaved themselves as sync slaves, no longer sounding like narcoleptic amateurs. It even worked at 3.3V, without the level shifter, so it seems Roland isn't too picky about the voltage, but it's all about the pulsewidth setting - check out the CV config menu page for that.

post-20226-0-33526800-1433412284_thumb.j

 

@smaudio:

the MC202 adds some extra time in the last step of every sequence

This seemed to happen only when my 202 was in 'play once' mode. When I saved a short pattern then went into cycle mode (shift -> cycle) the unwanted gap at the end disappeared.

 

I see that using a dedicated DOUT for din syn clocks is now the favoured route instead of J28. I haven't checked this out yet, I'm using a SEQ V4 anyway, and this post is long enough already so I'd best leave it there. I hope the above all makes sense and the scope pics aren't too shabby.

 

Cheers,

C

Edited by cmos

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I have yet to wire up my DINSYNC port but I have to ask what is a 541 and where do you place it?

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