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Re: Fairlight CMI [Re: SynaMax] #116712 01/10/20 08:06 PM
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Hej Tonhar,

No, I'm not Swedish, but I've lived in Sweden for the past 6 years.

What sort of response is the core program waiting for from the channel cards?

Re: Fairlight CMI [Re: SynaMax] #116798 02/02/20 10:52 AM
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[Linked Image from i.imgur.com]

Re: Fairlight CMI [Re: SynaMax] #116801 02/02/20 12:59 PM
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You got DOS to load? Cool!

Re: Fairlight CMI [Re: SynaMax] #116803 02/02/20 02:51 PM
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DOS has loaded for ages, the difference here is that the interrupt test no longer fails literally every interrupt check, just the Analog Card check.

Re: Fairlight CMI [Re: SynaMax] #116804 02/02/20 05:55 PM
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The channel card PTM tests are now fixed.

[Linked Image from i.imgur.com]

It helps to use the correct clock rates. While the channel card PTMs are almost clocked at 2MHz, and almost have external clocks of 250kHz, 500kHz, and 500kHz, the rates are in fact derived from the /CAS signal, which is in turn derived from the main CPU crystal rate of 40.21MHz.

I finally had a brainwave when I found that the timer tests would pass if I manually adjusted the PTM clocks up by half a percent, and then noticed that the main clock of 40.21MHz is almost exactly half a percent faster than a flat 40MHz.

Re: Fairlight CMI [Re: SynaMax] #116808 02/02/20 07:30 PM
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That's really cool. What's still failing?

Re: Fairlight CMI [Re: R. Belmont] #116809 02/02/20 07:57 PM
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Originally Posted by R. Belmont
That's really cool. What's still failing?


I'm reasonably sure the other PTMs are still clocked incorrectly. I haven't been able to work out where the "1CLK" and "2CLK" signals are coming from which clock the PTM on the Q133 or Master Card (I don't have the schematics in front of me, my TV is occupied at the moment).

As shown above, the AIC (Audio Interface Card) interrupt test fails, as the AIC interrupt is entirely unhooked up at the moment. The AIC schematics in the service manual are partly hand-written and the scan quality is rather poor, so I haven't been able to work out very much about the AIC. To be fair, neither was Phil, based on the September 2009-vintage driver.

The System 12 disks still report "Couldn't Load MIDI" and then hang.

The SMPTE/MIDI ("SMIDI") card is not yet fully hooked up, but I've made some good progress on it. It is however not related to the error that I just mentioned, because the System 12 disks don't even try to tickle FCA0, which is the access port to the SMIDI card.

The System 19 disk hangs without printing anything to the screen other than the initial loading message. It does, however, crater MAME's performance down to 9%. This is presumably because it's sitting in a tight loop, almost constantly toggling the selected memory map, which means every 10-20 instructions it's discarding and re-creating the memory map for CPU 1.

Re: Fairlight CMI [Re: SynaMax] #116810 02/02/20 09:11 PM
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I've got local fixes for that first one. Turns out that the /C3 clock on the video board's PTM is clocked at half the /CAS rate, and both it and the Master Card's PTM have an internal clock rate matching the /CAS rate.

[Linked Image from i.imgur.com]

Re: Fairlight CMI [Re: SynaMax] #116823 02/05/20 07:45 PM
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All interrupt tests now pass:

[Linked Image from i.imgur.com]

Re: Fairlight CMI [Re: SynaMax] #116824 02/05/20 07:55 PM
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Great to see how you're chipping away at this thing ... next up: the ker-klunk of the 8" disk drive that you can hear in some of the demo videos smile


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
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