error
Offline

so.  this is not only my first post here on chipmusic.org, after lurking for several months, it  also marks the first time I've ever registered or posted on any forum ever.   thought I  should get that out of the way.  you guys seem seem like  some legit cool cats.

I   emailed kitsch about this project a while back, before I had all of the parts, but now I'm in the home stretch  and  facing  some trouble. I  am trying to install a dp3t  make before break  toggle  connected to  an easy_clock (1/1,1/2 time)  and variable  clock.  so far I  can get it to run  correctly in  both fixed  positions,  but when I switch to 1/1 variable it freezes.  when in variable,   using  the pot  causes varied side to side jitter,  and  changes the pitch of the last note played,  but  games and lsdj freeze  and won't resume even when switched out of variable.   

also I  hope to not be so long winded here in the future,  my apologies.

error
Offline

I  should add  that the main objective in this project is for the modes to all be hot switchable.  that said, it  won't even boot  from cold in variable. also, switching to 1/2 works in  games every time,  but almost always causes lsdj  to give  the "don't panic" screen.  could it just be a bad ltc  for the variable problem?  anyone  with insight?

friendofmegaman
Offline
CA

Hm... interesting. I have the same problem with the x1 and x1/2 (bloody images freezes when I switch between them), but almost no problems with LTC (LSDJ crashes occasionally but it's very rare). What schematic did you use? I used this one http://www.instructables.com/id/The-Ult … Pitch-Mod/ and it works fine for me.

Last edited by friendofmegaman (Mar 27, 2014 9:39 pm)

error
Offline

I definitely checked out that same instructable, as well as the instruction image on kitsch-bent. They're super clear and look so easy. The tricky part that I can't seem to find specifics about is if the ltc plays nice with an on/on/on switch. I removed the stock crystal, per the instructions for the easy-clock. The switch is double poled, so I have the easy clock at 1/1 in two positions, 1/2 in the third position, and the ltc wired in to one of the positions that also gives 1/1. I have ltc clock coming out of the switch and going to the same point on the pcb as the easy-clock, the spot that the instructable points out.

What kind of switch are you using? Are you trying both mods on the same gameboy? Did you remove the stock crystal? It seems like there's something to learn from the fact that we're having such similar but opposite problems, if that makes sense.

friendofmegaman
Offline
CA

In my previous project I used LTC only without additional oscillators, and I used a two-position toggle switch connecting clock output of LTC and the corresponding pin on the DMG PCB.

Yesterday I played with two oscillators - wired them with the same exact kind of toggle switch, as it shown in the instructable above. I removed the stock crystal and re-wired it with the 7.3 MHz. I see the screen becomes lighter / darker when I switch between them (which makes sense) but the image freezes and nothing's going on.

Last edited by friendofmegaman (Mar 27, 2014 11:16 pm)

error
Offline

to my understanding,  using two crystals and a switch means  you need to turn the system off in order to change clock speed. kitschbent sells an ic  that takes the place of both crystals.  it's on a tiny pcb,  and it allows switching while the system is on. if  you're just using crystals that might be why the system is freezing when you switch. I  ordered crystals intending to do the same thing you're attempting,  then learned about the problem before they ever even arrived.

friendofmegaman
Offline
CA

I see... well it means I need to find out how to make them switchable on the fly. I could always buy from Kitsch of course, but it's more fun doing things yourself smile

error
Offline

If you make any progress with switchable crystals, please let me know! I think that's the crux of my problem- the ltc may only work in cases where it's oscillating a crystal clock, and the easy_clk Seems to be a silicon clock. I suspect that's the issue for me.

friendofmegaman
Offline
CA

One option is to use LTC with some discrete voltage values to have 1/2 frequency...

friendofmegaman
Offline
CA

Another option is to attach the second leg of the 1/2 crystal to the same pin you wire LTC1799, I can't test it right now, but I'll let you know smile

friendofmegaman
Offline
CA

Mystery resolved. Google frequency divider smile

This will go I think http://pdf.datasheetcatalog.com/datashe … ICS542.pdf

EDIT
But it seems that for division-by-2 a simple D flip-flop will go.

Last edited by friendofmegaman (Mar 30, 2014 8:13 am)

error
Offline

hooked up  the ltc  without any other mods,  straight  with no switch  and still had problems.  just realized I unwittingly  had a  linear pot instead of an audio taper.  New pots are  on the way,  hoping that fixes the problem.  anyone have  these issues with linear pots on the  variable clock  mod?

friendofmegaman
Offline
CA

Why do you need an audio taper? I used a linear pot in my last mod, worked fine.

error
Offline

fair enough. my linear pot was a salvage,  so at this point I'm hoping  that it was just damaged  or unreliable,  causing a  ruckus.  the multimeter seemed to say it was good,  but I'm no great shakes at this stuff so I  could have been wrong. fingers crossed that a fresh  shiny new pot   exactly to spec does the trick

error
Offline

well. new pot- still no dice.

as it stands, I cannot get the variable clock to function properly,  even when  wired with a new pot  and no switch.  at this point should I  assume that the ltc  itself is funky?

friendofmegaman
Offline
CA

can you share a picture of your wiring?