4MB Upgrade & 16MHz Booster progress

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 01, 2015 2:54 pm

SteveBagley wrote:
exxos wrote:Also it seems to be running the CPU at 16mhz all the time, we never got that to work, there was some talk about it a few weeks back in this thread. Unless the issues were just with CPU <>MMU issues. If both are running at double speed then it could be possible the CPU could run 16mhz all the time. But then is also a big question mark on the E-clock on the CPU also.


If everything is sped up to 16MHz then the relation between DTACK, AS, and xDS lines will still be the same so everything should work fine, the problem comes when some parts are running at 16MHz and others at 8MHz because then the timing relationships expected by the CPU don't match what it gets…

As for the 6850s, I wouldn't be surprised if the 2MHz and 1MHz parts are identical and that each batch of chips are sampled to see what speeds they reliably work at, and then the whole batch labelled accordingly. Often you can find that several of the 1MHz parts are happy to run at 2MHz, but are just labelled as 1MHz.

Steve


Its possible some parts might overclock. Though I have ordered in some 2mhz ones to swap out just to be sure they are not going to be a problem. I needed to get some for the booster project anyway.

The 16mhz <> 8mhz clash is what worries me. As already known/tested the CPU will not run at 16mhz all the time. If the CPU can talk to RAM at 16mhz then thats fine, though where does GLUE fit into this. It looks like it must be running at 8mhz still. Though in my mind that is a GLUE 8mhz vs CPU & MMU @ 16mhz.

I was thinking of a more complex switch, to switch the MMU into 16mhz mode along with the CPU when the Shifter is not being accessed, then slowing the whole machine back down to default speeds. Though according to that file Arne posted, they are doing no clock switching like that. Just running the CPU at 16mhz all the time plus the MMU. The only fix is that DE part. Which would seem a little pointless if GLUE is running at stock speeds anyway. If all the clocks are still in sync with the master 32mhz then it wouldn't matter anyway.

I wonder if the DE thing is a fix for the "inverted" clock which happens earlier in the circuit. If all my assumptions were correct then it would pretty much render the entire mod pointless. A easier way would be just to buffer the 32mhz clock (delays wouldn't matter at that point) then feed the shifter and MMU with a new buffered 32mhz clock. Cut the 8mhz line from the MMU and connect it to the 4mhz line (so double clocked becomes back to 8mhz for the rest of the bus, GLUE etc). CPU gets 16mhz from the 8mhz MMU output, and that would be it. This would then suggested the CPU will not run at 16mhz all the time simple due to RAM access, and if RAM is double clocked, then the CPU is happy to run at 16mhz all the time. A lot of ifs/buts/assumptions with it all.....
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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Thu Jan 01, 2015 3:17 pm

Arne wrote:As I understand the meaning of the DE line Glue tells MMU to stop any RAM access by DMA/CPU and let the Shifter get the data to be displayed.


DE is simpler iirc, it just tells the MMU when to start passing data to the shifter -- the old overscan mods just change the period of this to extend the display.

That'll explain why DE is being anded with the '2MHZ' clock to stop the data being sent to the shifter too fast. Normally, the MMUs clock is at the right speed so DE can just be asserted for the line period, but with the MMU running twice as fast that would shift 80 words to the shifter instead of 40 (in high res) and mid-way through the shifter handling the last word. Anding with the clock means that the MMU shifts a word, then things the display is disabled when it should (at the higher speed) shift the next to the shifter, then it's enabled again for the next and so on.

I wouldn't be surprised if the phase relationship between the 2MHz clock, DE and Hsync is responsible for the screen bend. The original overscan document has some interestings comments along those lines...

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 01, 2015 3:41 pm

I thought GLUE was controlling DE to MMU/Shifter ?

If MMU is driving DE to shifter then that would make more sense. Though I thought GLUE drove DE, so nothing would change sync or clock wise if GLUE was still being clocked at the default 8mhz.

If MMU is driving DE, then as MMU is double clocked, then DE would need some attention there in that case.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Thu Jan 01, 2015 3:53 pm

exxos wrote:I thought GLUE was controlling DE to MMU/Shifter ?

If MMU is driving DE to shifter then that would make more sense. Though I thought GLUE drove DE, so nothing would change sync or clock wise if GLUE was still being clocked at the default 8mhz.

If MMU is driving DE, then as MMU is double clocked, then DE would need some attention there in that case.


AIUI, GLUE generates DE which tells the MMU and shifter when to display graphics (instead of border) -- it's fed to the MMU and shifter (as well as the MFP to generate the Timer-B interrupt on one of the edges).

The MMU is responsible for generating the addresses for RAM, and telling the shifter to pick them up off the memory data bus. It does this based on it's clock, but only when DE is high. If the MMU is overlocked, it's going to fetch data for the shifter at twice the speed. This hack seems to get around it by anding DE with the 2MHz clock -- so DE is now pulsed so that the MMU doesn't update it's counters and load the shifter too fast. Note that shifter still gets the DE direct from GLUE -- which causes it to display things as normal.

There's a good description in the OVERSCN3.ZIP on http://atari4ever.free.fr of how the shifter/mmu/glue interact normally to create an image.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 01, 2015 4:07 pm

SteveBagley wrote:
AIUI, GLUE generates DE which tells the MMU and shifter when to display graphics (instead of border) -- it's fed to the MMU and shifter (as well as the MFP to generate the Timer-B interrupt on one of the edges).

The MMU is responsible for generating the addresses for RAM, and telling the shifter to pick them up off the memory data bus. It does this based on it's clock, but only when DE is high. If the MMU is overlocked, it's going to fetch data for the shifter at twice the speed. This hack seems to get around it by anding DE with the 2MHz clock -- so DE is now pulsed so that the MMU doesn't update it's counters and load the shifter too fast. Note that shifter still gets the DE direct from GLUE -- which causes it to display things as normal.


That makes sense then. I was thinking GLUE was doing the counting not the MMU. So if MMU does counting based on DE state (not just simply counting per clock cycle) then that is actually pretty clever. So DE would need some hackery to slow down the MMU counting as you suggest.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Thu Jan 01, 2015 4:32 pm

I removed part of the plasic housing of the MFP around CLK4, but something went wrong: I now have a short circuit between the open CLK4 pin of the MFP and GND. Have to remove the MFP completely and order new parts. That will take some time.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 01, 2015 5:27 pm

Arne wrote:I removed part of the plasic housing of the MFP around CLK4, but something went wrong: I now have a short circuit between the open CLK4 pin of the MFP and GND. Have to remove the MFP completely and order new parts. That will take some time.


PM sent. I could probably help with some spares as I have a spares STFM, though not sure whats blown on the board so would have to test chips once by one.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Thu Jan 01, 2015 6:45 pm

exxos wrote:I could probably help with some spares as I have a spares STFM,

Thanks, but not needed. I can get 2 DIL48 MFP here for 10,-EUR.
Sometimes the CRT tells me (always if the HSync/VSync are out of range) that either HSync or VSync is missing. I don't think it's a broken track on the PCB but suspect the wonderful PLCC68 socket of Glue. Do you know a source for these sockets?

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 01, 2015 7:06 pm

Arne wrote:Sometimes the CRT tells me (always if the HSync/VSync are out of range) that either HSync or VSync is missing. I don't think it's a broken track on the PCB but suspect the wonderful PLCC68 socket of Glue. Do you know a source for these sockets?


Unfortunately no. I did spend some time looking a few weeks ago, and have others also. The only source is the motherboards themselves.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby GadgetUK164 » Fri Jan 02, 2015 12:43 am

Arne wrote:
exxos wrote:I could probably help with some spares as I have a spares STFM,

Thanks, but not needed. I can get 2 DIL48 MFP here for 10,-EUR.
Sometimes the CRT tells me (always if the HSync/VSync are out of range) that either HSync or VSync is missing. I don't think it's a broken track on the PCB but suspect the wonderful PLCC68 socket of Glue. Do you know a source for these sockets?


AtariFreakz on eBay sells those sockets - £5 each, a bit pricey but he does still have some I think.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Fri Jan 02, 2015 9:44 am

GadgetUK164 wrote:AtariFreakz on eBay sells those sockets - £5 each, a bit pricey but he does still have some I think.

Thanks for the hint. Couldn't find them in his current auctions though. But if they are just unsoldered from scrap-boards then they are not better than mine. I once had access to some sockets with gold plated contacts, but just could get a hand full of these.
Found an MFP in my spares box. Will cut the broken MFP and replace it during the weekend. Will take the Logicport from work to check some signal relations.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Fri Jan 02, 2015 9:49 pm

I'm a bit out of luck right now.
Replaced the MFP. It now gets 4MHz, PSG gets 2MHz, CPU gets 16MHz, MMU gets 32MHz, Glue gets original 8MHz,
i.e. PSG/ACIA(Pin 3 & 4) get original clocks, E-Clock is 1.6MHz.
I now get the ST-LOW/MED HSync/VSync. MONO_DET is low at the MFP. As I am sure the original TOS 1.00 ROMs aren't fast enough I put a TOS 2.06 card in. I'm using 120ns EPROMs. Might that be too slow? I have brand new AMD 70ns. Shall I try these?
I solved the missing HSync: cut track under the MFP. Now /HALT is asserted, /BERR is not. Any idea?

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 02, 2015 10:18 pm

120ns will be fine. Though these problems might be caused by that mod ? If you still got it installed, I would document where all the wires go, and remove it, and get the stock ST working first.. 70ns RAM will work fine for either CPU speed.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 10:24 am

I understand the purpose of building it back to 8MHz, but I am afraid I will not find all the track cuts I made...
So I want to stick to the current configuration.
About that TOS 2.06 EPROMs. The decoding GAL is 20ns. This adds to the 120ns, doesn't it? Still fast enough?
PS/2 SIMM is populated with 70ns DRAMs.
Glue is not asserting /ROM2... never. I checked that Glue in a 1040 and it boots into the desktop. So at that point even the diagnose-kit is of no purpose.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 03, 2015 10:41 am

When I tried 20ns GAL it wouldn't work with my booster stuff. It was the main "gottcha" a few months back. When I switched to 7ns GAL the problems went away. So I would defiantly not use a 20ns GAL for anything. If GLUE is doing the decoding for ROM, then it *might* be ok at 20ns. GLUE decoding is happy at 200ns+

I don't know how that TOS206 thing is working in your case, maybe just put the TOS104 ROM's back in and unplug the TOS206 ones ? Let GLUE decode TOS like normal without anything else involved.

I don't know if that TOS206 bit, is actually running at 16mhz though ? See this is where it gets confusing. We used 7ns GAL to decode TOS206, but the ROMS had to be 120ns or 100ns to talk to the CPU at 16mhz. Though if GLUE is doing the decoding, then GLUE will issues DTACK based on the 8mhz clock, So even if the CPU if running at 16mhz at that point, TOS will still run at stock speeds.

That is the main problem again of the CPU running at 16mhz while the rest of the bus like GLUE decoding is at 8mhz. I assume the thing can work like that in your case with that mod. As the CPU would just wait for glue to issue DTACK regardless of what the CPU speed is.

In your case you don't know if the mod is causing the problems, or there is something wrong with the ST itself. With double ended problems like this it will be hard to do any in depth fault finding as the problem could be anywhere.

Just one other thought, what CPU have you got in there ? Assume you got a 16mhz part, I can't tell from your image, looks like a P8 ?
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 11:01 am

exxos wrote:I don't know how that TOS206 thing is working in your case, maybe just put the TOS104 ROM's back in and unplug the TOS206 ones ?

Wilco. Just have to find TOS in 6 ROMs. I got many 1.02 in 2 ROMS... Recently burned KAOS into 6 ROMs for an 1040.
But I don't think this will solve anything as it cannot be the source of not asserting /ROM2.

exxos wrote:Just one other thought, what CPU have you got in there ? Assume you got a 16mhz part, I can't tell from your image, looks like a P8 ?

16MHz from ST (i.e. SGS-Thomson)

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 11:22 am

Now it's booting. :mrgreen:
I put in an 8MHz CPU and let it run at 8MHz. Now testkit is running RAM test...

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 03, 2015 12:52 pm

Arne wrote:Now it's booting. :mrgreen:
I put in an 8MHz CPU and let it run at 8MHz. Now testkit is running RAM test...

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 1:05 pm

I checked the 16MHz CPU in my 1040: it's working. I put it into the 520 and clock it with 16MHz: nothing. With 8MHz it shows the empty desktop but screen is shifted to the right by some characters. Probably because the DE patch is still active.
Not exactly what I aimed for, but a basis to continue...

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 10:27 pm

Small progress.
I removed the 6 EPROM KAOS and put in another TOS 2.06/IDE card (DIY project from German magazine c't).
With the P16 CPU and 16MHz and with the Motorola P8 CPU at 8MHz I get this picture:
Image
With a EF68000P8 (stamp on top is "8547 8" so I guess it's manufactured 47th week of 1985) I don't get a picture at all,
but this CPU runs in my 1040.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Sat Jan 03, 2015 11:22 pm

Arne wrote:Small progress.
I removed the 6 EPROM KAOS and put in another TOS 2.06/IDE card (DIY project from German magazine c't).
With the P16 CPU and 16MHz and with the Motorola P8 CPU at 8MHz I get this picture:
Image
With a EF68000P8 (stamp on top is "8547 8" so I guess it's manufactured 47th week of 1985) I don't get a picture at all,
but this CPU runs in my 1040.


That's sort of what I'd expect with a 16MHz MMU and DE not being changed -- if you put your scope on DE into the MMU do you get a signal that it is high for most of the line period? The hack describes ANDing it with the 2MHz clock to try and get it back to a 640x400 display, so I'd take a look around there?

Also check the pinouts for the signals it is asking for because I think one of them (2MHz clock) in the text was different to the schematics online when I compared them the other day.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 03, 2015 11:31 pm

Arne wrote:Small progress.
I removed the 6 EPROM KAOS and put in another TOS 2.06/IDE card (DIY project from German magazine c't).
With the P16 CPU and 16MHz and with the Motorola P8 CPU at 8MHz I get this picture:
Image
With a EF68000P8 (stamp on top is "8547 8" so I guess it's manufactured 47th week of 1985) I don't get a picture at all,
but this CPU runs in my 1040.


Looks similar to the results I had when I double clocked the shifter. If the shifter is running with the normal 32mhz clock then its being loaded to fast, which is probably what that DE mod is there to solve ? But that is really good progress all the same :)

I would stick with your P16 CPU, the P8s don't work at 16mhz, at least not the ones I tried. I don't know if your CPU is boosted to 16mhz at the moment ?
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 03, 2015 11:49 pm

exxos wrote:I would stick with your P16 CPU, the P8s don't work at 16mhz, at least not the ones I tried. I don't know if your CPU is boosted to 16mhz at the moment ?

I get that picture with P16@16MHz and P8@8MHz!
I will have a look at the DE patch and attach the Logicport from work.

One thing I was thinking about your mod: if you double clock Glue then it will generate /DTACK twice as fast, which shouldn't be a problem for TOS EPROMs if they are fast enough. But Glue will also speed up /DTACK on /ROM3 and /ROM4! This may render cartridges useless.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 03, 2015 11:55 pm

Arne wrote:
exxos wrote:I would stick with your P16 CPU, the P8s don't work at 16mhz, at least not the ones I tried. I don't know if your CPU is boosted to 16mhz at the moment ?

I get that picture with P16@16MHz and P8@8MHz!
I will have a look at the DE patch and attach the Logicport from work.

One thing I was thinking about your mod: if you double clock Glue then it will generate /DTACK twice as fast, which shouldn't be a problem for TOS EPROMs if they are fast enough. But Glue will also speed up /DTACK on /ROM3 and /ROM4! This may render cartridges useless.


Assume the MMU is still running double speed there ?

Glue is tricky, you have video syncs and 2mhz and 500khz output from it. DTACK will be faster. Though with all the "side effects" its not really possible to boost GLUE speed. We did seperate decoding for TOS104 and TOS206 via GAL logic and just isolate /AS so GLUE would never "see" the ROM address ranges.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sun Jan 04, 2015 10:22 am

exxos wrote:Assume the MMU is still running double speed there ?

Yes. It's Stephan's patch with the 3 74xx ICs and I'm using the 2nd FF for generating 4MHz (MFP).
This morning I switched the 520 on and got a perfect picture. 8O
But only one time. I was watching the memtest running as suddenly the picture scrambled again.
Switching on/off a dozen times didn't change anything. Used ice-spray to cool MMU/CPU down but to no avail.
I wasn't moving anything while the memtest ran - just watched. Okay, I didn't stop breathing... :lol:


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