Project: HDMI/DVI out for STFM

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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Tue Dec 04, 2018 10:47 am

ijor wrote:
Tue Dec 04, 2018 10:24 am
Thanks Smonson, but this is on your system, not on one of the systems that fails, right? And again, more important, all the scope captures might be on a good read, not on a "bad" one. You cannot take for granted they would be the same. Yeah, they are not likely to be different. But as you agree, all the options are unlikely, so you have no choice but to consider the unlikely.
Yes, but the chances of it being different on Icky's machine are now billions to one, because Icky's board worked fine on my machine, and we've already confirmed that it resembles this scope observation on Icky's machine on his LA, and the verilog for generating this signal is straightforward, and we've already observed a different phenomena that can explain all of the symptoms (D9 being high).

I'm open to the possibility that there's something wrong with F_BUS_DIR, but the chances seem to be about as low as if aliens were doing it.

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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Tue Dec 04, 2018 10:50 am

sandord wrote:
Tue Dec 04, 2018 10:30 am
I was wondering if, once this all works flawlessly, it would be possible to have the FPGA optionally output the video using a "scanline look" filter. You know, like the OSSC and the Framemeister do.
You bet! I have already added a jumper to the circuit board to enable this, and it should only be a small amount of work in Verilog. Actually I should have done it already but I've become obsessed with finding out where this opaque read issue is coming from :wink:

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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Tue Dec 04, 2018 10:51 am

...by the way Ijor, have you tried your HDMI mod to see if it works on your machine(s)?

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sandord
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Re: Project: HDMI/DVI out for STFM

Post by sandord » Tue Dec 04, 2018 10:53 am

Smonson wrote:
Tue Dec 04, 2018 10:50 am
sandord wrote:
Tue Dec 04, 2018 10:30 am
I was wondering if, once this all works flawlessly, it would be possible to have the FPGA optionally output the video using a "scanline look" filter. You know, like the OSSC and the Framemeister do.
You bet! I have already added a jumper to the circuit board to enable this, and it should only be a small amount of work in Verilog. Actually I should have done it already but I've become obsessed with finding out where this opaque read issue is coming from :wink:
Of course, first things first but it's great to hear!

With all these switches adding up (TOS/floppyAB/Accellerator/Scanlines), we might nead a switch board :lol:

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Smonson
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Re: Project: HDMI/DVI out for STFM

Post by Smonson » Tue Dec 04, 2018 10:55 am

sandord wrote:
Tue Dec 04, 2018 10:53 am
With all these switches adding up (TOS/floppyAB/Accellerator/Scanlines), we might nead a switch board :lol:
Anyone who installs one of these mods is also gonna want a high/low res switch... I didn't add one to the HDMI mod board itself, because it's really between the user and TOS, nothing to do with the shifter. If it was on the mod board it'd just end up having some more wires that go somewhere else anyway.

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Re: Project: HDMI/DVI out for STFM

Post by sandord » Tue Dec 04, 2018 11:02 am

Smonson wrote:
Tue Dec 04, 2018 10:55 am
Anyone who installs one of these mods is also gonna want a high/low res switch... I didn't add one to the HDMI mod board itself, because it's really between the user and TOS, nothing to do with the shifter. If it was on the mod board it'd just end up having some more wires that go somewhere else anyway.
Good point. So, even one more switch. I'm thinking it would be nice to have a single 8 pin connector or something on the rear of the ST that takes a small 3D printed box with rocker switches on top of it. Not too different from a rear cartridge like the C64 has but much less protruding.

Until now I have been drilling holes in my 3D printed Gotek bracket, but it hasn't enough space for more than 2 switches.

Gunstick
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Re: Project: HDMI/DVI out for STFM

Post by Gunstick » Tue Dec 04, 2018 11:04 am

For testing shifter accuracy with the bus capacitance remanance, you can use this and compare if it looks like that.
(at minute 54)
:D

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Re: Project: HDMI/DVI out for STFM

Post by ijor » Tue Dec 04, 2018 11:16 am

Gunstick wrote:
Tue Dec 04, 2018 11:04 am
For testing shifter accuracy with the bus capacitance remanance, you can use this and compare if it looks like that.
It you are relying on the unused bits, it won't work on this board. I mean, you won't get the same effects because all the data lines goes through a single transceiver.

Btw, did you try that with all the Shifter versions? I didn't test, but I suspect the behavior would be different with an IMP shifter. There are also minor differences when using an IMP MMU as well.
http://github.com/ijor/fx68k 68000 cycle exact FPGA core
FX CAST Cycle Accurate Atari ST core
http://pasti.fxatari.com

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Re: Project: HDMI/DVI out for STFM

Post by ijor » Tue Dec 04, 2018 11:37 am

Smonson wrote:
Tue Dec 04, 2018 10:51 am
...by the way Ijor, have you tried your HDMI mod to see if it works on your machine(s)?
Sorry, not yet. It's not easy for me.

Btw, Gunstick's post reminded me. You shouldn't drive the data bits that Shifter doesn't use. A real shifter never drives those bits. Well, at least the gate array versions. Can't say for sure about IMP Shifter.
http://github.com/ijor/fx68k 68000 cycle exact FPGA core
FX CAST Cycle Accurate Atari ST core
http://pasti.fxatari.com

czietz
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Re: Project: HDMI/DVI out for STFM

Post by czietz » Tue Dec 04, 2018 5:51 pm

Sorry, I missed a lot of posts in this thread the last few days. But iirc Smonson made a test program that generates a trigger signal upon faulty reads. Wouldn't the best way forward be to use that test program and to probe (with a scope) e.g. D9 at every buffer, level shifter or latch it passes through. Somewhere it must get corrupted. Then look at the direction and/or output enable signal of the IC where D9 is not passed through correctly.

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