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CT60 and related things BBS
| CT60 SDMA timing issue? |
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Posted by: Coda
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Jun,17.2013-13:19
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I've spent a week - literally - hunting down this problem. Actually 2 problems, one of which I'm not sure is actually a real h/w problem or a software bug. I have set up my Cubase Audio system again, because I will start at Uni a short course on music production, and I want to use the old school DAW instead of Garageband/Logic like everyone else will, it's a basic course anyway so CAF will do the job.
Anyway, I recorded a short test audio in via the FDI from a minidisc to a track on CAF. When playing back, I get crackles on the audio. Okay, now you say: "Yes, that's the SDMA bug/Clock patch, whatever", and you'd be right, that's what it looks like. However, my CT60 was installed with solders (50/25mhz boost to F030, and supplied SDMA term resistor (47R) was in place. I don't remember in 2005 having these audio crackles, and nothing changed since then, except I updated the ABE and SDR to V7. The problem manifests in 060 (any CPU clock, boosted or not) or 030 mode.
The second issue is the SDMATEST.PRG. If I start it, and first press '/' to change the SDMA clock to 32mhz I hear a very loud buzz through the headphones like a chainsaw, which changes frequency with the +.- keys. If I press space (Play), the noise stops. When pressing space a second time, the noise does not return. I'm wondering if this is a bug in SDMATEST.PRG, not initialising the SDMA hardware correctly. SDMATEST.PRG works otherwise as expected and with 4 channels there are no audio defects.
Audiotracker 1.66/2.01 works without audio defects/problems, it's just CAF and all patches (excep060.prg, caf_fix.prg, and patched cubase.prg) are used.
So, in the last week I have:
* Replaced the F030/CT60 10 pin interface cable with new one
* Resoldered all clock wires
* Checked board for any old solder splashes/dust
* Traced and checked clock lines for 030, SDMA (CPUCLOCKA, 25Mhz, 32mhz from ex-DSP Oscillator), DSP clock (from CT60).
* Refitted old 74F04 clock patch that was removed when I fitted the CT60 years ago
* Changed clock patch to 74F08 new recommended by Rodolphe (according to Doitarchive anyway) using one gate to boost the expansion port clock.
* Used a second gate of 74F08 to boost SDMA clock
* Changed half moon solder jumpers a couple of times
* Cut SDMA clock trace before term resistor, and fitted new shielded RG59/U cable from clock near CT60 directly to SDMA chip.
* Tried 100R term resistor on SDMA
* Tried ct60tos.bin from 1.03c and 2.01
* Probably more things I cannot remember
None of these had any effect, although one thing was interesting. When I boosted the SDMA clock with the second gate of the 74F08, the IDE disk speed appeared to rise. The boot bench went from the usual 7mb/s to over 8mb/s. I don't know if that number is useful indication of anything as I don't know how it is derived. I had to revert this modification anyway because system would lock up at the desktop.
This morning I decided to downgrade ABE/SDR to V5M. Audio crackles are gone in CAF. Chainsaw with SDMATEST.PRG remains.
I wouldn't say there's a bug in the latest CT60 firmware, I guess it's a fix for other problems either in the CT60 or on the F030 board itself, to help with CTPCI. I did read on some page a quote from Rodolphe something like "I will add a wait state SDMA transfer..." due to the bug in the Videl. I'm wondering in what firmware this was applied...
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Topic
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Posted by
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Date
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CT60 SDMA timing issue?
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Coda
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Jun,17.2013-13:19
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Re: CT60 SDMA timing issue?
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ggn
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Jun,17.2013-15:24
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Re: CT60 SDMA timing issue?
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Coda
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Jun,17.2013-16:39
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Re: CT60 SDMA timing issue?
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evil
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Jun,17.2013-17:38
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Re: CT60 SDMA timing issue?
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Coda
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Jun,17.2013-18:02
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Re: CT60 SDMA timing issue?
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ggn
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Jun,17.2013-17:41
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Re: CT60 SDMA timing issue?
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Coda
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Jun,17.2013-18:06
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Re: CT60 SDMA timing issue?
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ggn
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Jun,18.2013-21:43
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Re: CT60 SDMA timing issue?
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Coda
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Jun,18.2013-21:50
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Re: CT60 SDMA timing issue?
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dml
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Jun,28.2013-12:28
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Re: CT60 SDMA timing issue?
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Coda
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Jul,05.2013-17:09
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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