phantom bus accelerator & clock patch

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exxos
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phantom bus accelerator & clock patch

Post by exxos » Sun Feb 24, 2019 11:10 am

I looked into my clock patch again on my second Falcon and I think I know why the phantom patch needs the second buffer chip for the SDMA.

Adding loading resistors on the SDMA side only reduces the voltages and issue. A couple variants seem to divide the voltage in fact. IIRC the phantom used a really slow buffer to "cover up" the issues. Adding a loading capacitor seems to make things worse, when it should do the same as the resistor and smooth out the signal.. Basically the line is oscillating on some falcons it seems. heavy load resistors on the SDMA clock just halves the voltage and the issue. Slow buffer chips get around it as they are to slow to react. I don't like either solution. Both put a lot of mA into the long trace in the area of 100mA! I'm surprised nobody mentioned interference issues with so much RF going though a long 16-25MHz track.

So I've done a new clock buffer design, but I don't have any bus speeders to test it.. can anyone help try it out once I get a couple built ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Steve
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Re: phantom bus accelerator & clock patch

Post by Steve » Sun Feb 24, 2019 11:55 am

I would happily test it in my phantom Falcon just depending on the level of modification required. I currently have my 'home made' phantom clock patch, so it has the cut track at the sdma etc etc. If I had to repatch the trace and stuff I might not go down that route since it would require a bit too much messing, especially since my falcon is running like a dream already :)

Are you saying that your new clock patch will have added stability over the Phantom one?

Also have you ever had a conversation with the guy who made the Phantom patch? I think his name is ctirad I think, he's on atari forum. You guys would probably learn from each other.
Falcon ct60e 060 - 256mb ram - phantom bus and dsp accel // Atari TT - Thunder and Storm IDE 64mb ram - Lightning VME - USB LAN - Ati Mach64 2mb // Atari STM 4160 - 4MB ram - 16Mhz exxos 1.5 booster - Ultrasatan

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Re: phantom bus accelerator & clock patch

Post by exxos » Sun Feb 24, 2019 12:09 pm

Steve wrote:
Sun Feb 24, 2019 11:55 am
I would happily test it in my phantom Falcon just depending on the level of modification required. I currently have my 'home made' phantom clock patch, so it has the cut track at the sdma etc etc. If I had to repatch the trace and stuff I might not go down that route since it would require a bit too much messing, especially since my falcon is running like a dream already :)
Hmm.. So was the track cut both ends and feed with a new wire ?

Also assume your patch had the "second" buffer chip ? Really if the track is replaced, there shouldn't be any need for the second buffer. Something like 68R in series with the line with the normal clock patch should be enough.
Steve wrote:
Sun Feb 24, 2019 11:55 am
Are you saying that your new clock patch will have added stability over the Phantom one?
No way to know until its tested.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: phantom bus accelerator & clock patch

Post by Steve » Sun Feb 24, 2019 12:12 pm

I'll post some pictures when I get home, just out to lunch at the mo :)
Falcon ct60e 060 - 256mb ram - phantom bus and dsp accel // Atari TT - Thunder and Storm IDE 64mb ram - Lightning VME - USB LAN - Ati Mach64 2mb // Atari STM 4160 - 4MB ram - 16Mhz exxos 1.5 booster - Ultrasatan

ctirad
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Re: phantom bus accelerator & clock patch

Post by ctirad » Sun Feb 24, 2019 9:23 pm

Hi, Steve pointed me to this forum. I'm the Phantom accelerator author. I'm ready to answer any questions.

BTW, I already have written some historical and technical info here, but the forum kicked me to the login screen when I tried to send it and everything was lost :(

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Re: phantom bus accelerator & clock patch

Post by exxos » Sun Feb 24, 2019 9:35 pm

ctirad wrote:
Sun Feb 24, 2019 9:23 pm
Hi, Steve pointed me to this forum. I'm the Phantom accelerator author. I'm ready to answer any questions.
Cool! Maybe you can clear up the slow buffer used for the sdma clock ?
ctirad wrote:
Sun Feb 24, 2019 9:23 pm
BTW, I already have written some historical and technical info here, but the forum kicked me to the login screen when I tried to send it and everything was lost :(
oh no :(

I don't know why it would do that, its not normal for it to log anyone out like that.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: phantom bus accelerator & clock patch

Post by exxos » Mon Feb 25, 2019 10:07 am

Steve wrote:
Sun Feb 24, 2019 12:12 pm
I'll post some pictures when I get home, just out to lunch at the mo :)
Maybe you can solder the SDMA wire to a pin on the main buffer chip (bypass the second one) and use a 100R in series with the SDMA clock ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: phantom bus accelerator & clock patch

Post by tuxie » Mon Feb 25, 2019 10:30 am

You have to use a extra gate for the sdma line, to get more time, then it is working well! Tested it on weekend again.

I have connected Pin 2 +3 together and 4 and 5 together, pin 6 connect the wire to SDMA

Pin 1 Input from Mainboard
Pin 2 Inverted Output
No extra capacitor is necessary!

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Re: phantom bus accelerator & clock patch

Post by exxos » Mon Feb 25, 2019 11:07 am

tuxie wrote:
Mon Feb 25, 2019 10:30 am
You have to use a extra gate for the sdma line, to get more time,
But why exactly ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: phantom bus accelerator & clock patch

Post by tuxie » Mon Feb 25, 2019 11:35 am

Just some thoughts, i think you give the SDMA more time to take over the Data. I tested it alot and also instable falcons are working better with this patch. Feel free to try it out! Its just how i do it, you can do what you want ;)

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