4MB Upgrade & 16MHz Booster progress

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Wed Jan 07, 2015 6:34 pm

troed wrote:So; When the mod is beginning to stabilize you _might_ want to look into synchronizing it so that the Shifter is in a "clean" state (zero internal registers filled) at boot - but until then I wouldn't worry about the screen effects you see.

It's annoying but does not lead to any misbehaviour of the ST.
I've seen in the schematics that neither MMU nor Shifter are connected to the /RESET line.
I assume that Shifter takes data from D0..D15 every time /LOAD is asserted? If so then we may attach 4 74F157 to Shifter's data bus - one input memory-data line, one pulled low to GND. MUXed line is connected to a Shifter data line. As long as /RESET is pulled low an additional GAL can simulate /LOAD assertions and count Shifter's A1..A5 up and pull D0..D15 low. When this is done the GAL just routes /LOAD and An through and the MUX are set to route memory-data bus through. Maybe there is some logic needed to delay /RESET's low state.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Wed Jan 07, 2015 9:48 pm

LOAD line could be isolated until the first V sync pulse happens. Idea being the Vysnc pulse resets the counters ready for a new frame. So if the shifter does not load any data until it sees the first Vsync pulse, then that would, I assume, Solve the turn on problems. Would probably need a flipflop, Tie its clear and/or rest lines to the ST's rest line to clear the output state. Then tie Vsync to the clock pin, and tie Data IP to 5V. So it becomes a "first frame skip" type circuit. The output would have to be used to isolate LOAD (I presume) from the shifter. Basically stop it loading any data until the first Vsync pulse happens. Depending on timings, it might need to skip the first 2 Vsync pulses, but thats not a problem. Shifter may display some corrupt data for a couple of frames on turn on, but nothing to worry about. DE could be used to solve that problem I guess also.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Thu Jan 08, 2015 9:32 pm

I am currently building this up, but while the LS74 halves the now 16mhz clock back to 8mhz for GLUE etc, the MMU has a 4mhz output which becomes 8mhz anyway, so really do we even need the LS74 ??

EDIT1: Actually I forgot the MFP needs 4mhz so eitherway would need a LS74 :(
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 11:34 am

I've got the mod working, (still not DE yet) but the ST only runs for a few seconds then resets. Does not seem to matter if there is a floppy in the drive or not. Though it will load my Auto folder program just before it resets. Without a floppy in the drive, it basically runs the same amount of time before the reset. Sometimes it just resets every second on power up. I guess its possible this MMU does not like 32mhz input.. Though I will try the DE patch as well just in case thats the problem. But wouldn't have expected it to do any harm other than video problems.

EDIT1: The DE patch hasn't changed stability. Though before I could make out the text on the screen of the auto folder program loading. Now I do not get that. Just a screen which looks like random memory locations. Like the shifter is loading data from somewhere else in RAM instead of video ram. I used a AND gate there as Arne reported that working OK. So can only assume at this point the mod does not work on STFM's for some reason, or the MMU does not like faster speeds. I will keeping working on it though.

EDIT2: It is also possible this mod only works with mono monitors ? I am running in normal ST resolution on boot so this could by why I am having video related problems ? I think the text which normally pretty much fills the screen, is squshed into half the screen how it was before the DE mod. Also the text only went half way down the screen. So this suggests the shifter is outputting data at double rate (IE 640px instead of 320px) then running out of data half way down the screen which then looks like just random RAM data. Though with the DE mod in place, it should have slowed down those timings back to default speeds. Though after the DE mod, its seems I just get the random RAM data and nothing else.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Fri Jan 09, 2015 3:16 pm

You reduced pullups on address lines to 4K7? Whats the pullups on data line?
Is you MMU socketed?
I know that I tried the mod with chipsets taken from MSTs, but found out that older chipsets from 520/260 work better for me.
MMU cannot assert reset so who can? Whats the state of /BERR before the reset?

On my 1040STFM schematics I see that A1..A23 are pulled high with 10K and A1..A16 are pulled low with 4K7. 8O
That's not the case on my 260/520 schematics (only pullups).

Make sure that DE_OUT is only connected to MMU, not Glue, Shifter, MFP.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 3:58 pm

Arne wrote:You reduced pullups on address lines to 4K7? Whats the pullups on data line?
Is you MMU socketed?
I know that I tried the mod with chipsets taken from MSTs, but found out that older chipsets from 520/260 work better for me.
MMU cannot assert reset so who can? Whats the state of /BERR before the reset?

On my 1040STFM schematics I see that A1..A23 are pulled high with 10K and A1..A16 are pulled low with 4K7. 8O
That's not the case on my 260/520 schematics (only pullups).



My MMU is in a socket, I actually put everything back to default and found the Shifter had died. So currently its back to that odd ghosted image (DE is not sorted at this point). It seems to give 1 or 2 bombs just before is resets.

I have not changed the pullups, simple due to the STs have been running with other 16mhz mods without changing them. Possible it could be aproblem with the MMU needed better pull ups. I will have to order some Monday.

The HC CPU I tried, I had to pull down instead of pull up for it to work. Though think they are all pull ups on the actual board by default.

I've not changed the reset resistors, wasn't really sure if there was any point as the machine boots up (kinda) anyway ?

I'm at a loss with this currently. I can put the DE mod back on, but last time I tried it, it made the video worse. At least at the moment I can see something going on. I've tried fiddling with all sorts, but currently the only find is the 32mhz does need to be inverted. If I run it via 2 inverters, not much happens, just white screen.

I'm taking the 4mhz line off the MMU, which is now 8mhz, running it via he flipflop for 4mhz, feeding that into the MFP. Thats all I have done. So it should be pretty much the same as your mod :roll:

DE OP... I cut the line right next to the MMU, so only that was feed from the AND gate. Though that part isn't connected up anyway. I assume you can get to desktop if you just connect GLUE DE to MMU DE directly (without AND) and you get that double image thing, with corruption on the bottom half of the screen.. but can actually get to desktop ?
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4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Fri Jan 09, 2015 4:44 pm

I wonder if driving GLUE directly off the MMU's 4-now-8 MHz output could be a problem?

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 5:05 pm

SteveBagley wrote:I wonder if driving GLUE directly off the MMU's 4-now-8 MHz output could be a problem?


I did wonder that, though as all the clocks would be in sync, the only thing that could happen is a inversion. I tried a inverter there, but didn't change anything. I was trying to keep as much clutter out of the clock lines as possible due to propagation delays. There could be some delays to long on the clock line somewhere. Though its hard to tell.

I did try feeding in the shifters 16mhz into the 74F74 at one point, though I didn't add another for the MFP, so that was being driven at 8mhz instead of 4. but it didn't make any difference with anything. I half have a feeling the MFP could run at 8mhz at this point. I am using a F74, the diagram said LS74, but I think Arne said he tried both and didn't make any difference.

Its odd as it always seems to crash just after it appears to load my auto folder program, I guess its just before it changes screen resolution for desktop. Though even without a floppy in, it seems to always take about 4 seconds before it resets. So loading data from floppy or not doesn't seem to matter.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 6:37 pm

I stole some pull ups form a old STFM, put them on the address bus, still same problems. So I tried more pull ups on the data bus, and this time it seems to crash with 2 bombs, and wait a second before it resets. So overall, not a pull up issue I think.

EDIT1: I tried the 16mhz clock and downclocked it via F74, also downclocked again for 4mhz. Same problem. Though the screen went black that time, but still floppy activity. So I inverted the 16mhz clock, and now just a white screen, still seems to be loading my auto program, but just resets just the same. Only this time I do not see the text loading on the screen, whereas when I used the MMU clock (4mhz line for 8mhz) I did. So god knows.. Nothing else to try now surely ?? Think I am starting to see why this mod is more "well know" :roll:

EDIT2, I have linked the 8mhz output from the MMU (now 16mhz) and used that line, now I don't need the inverter, but still same problems. In fact now its just 2 bombs as soon as it access floppy drive so what ever the problem is seems to be just getting worse.
Last edited by exxos on Fri Jan 09, 2015 10:22 pm, edited 1 time in total.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 9:07 pm

Some progress at long last. It seems the TOS ROMs are are fault here. I am now booted to desktop like Arne got before the DE mod. So either this mod does not work with lower versions of TOS, or the TOS ROMs have to be fast ones. Though as the GLUE still runs at 8mhz, which controlls the ROMs, I really do not understand why the ROMs need to be faster ?!
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 9:46 pm

32_result.jpg


Also investigated the MFP. At 8mhz input I get the wrap around thing like Arne gets. Though its about the size of the window buttons (like close button, or the width of the slider bar on right of a window). On 4mhz it does not happen. I suspect Arne running in mono causes the "wrap around" to be larger. Though There is not speed difference in GB results on 4mhz or 8mhz input.

I have noticed while it has been sat on that screen, that every few seconds the green background goes black for a split second, not sure why that is. Though possible it needs a delay in the DE line.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby rpineau » Fri Jan 09, 2015 9:56 pm

The MFP really need 4MHz as the base frequency is used for the timers and without patching the TOS (and other application using the MFP timers) you'll run into issues.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Fri Jan 09, 2015 10:48 pm

Yep, as 8mhz already breaks video I think leave the poor guy alone :)

Monday, I will put back the current booster to basic stuff. Then Replace TOS with TOS206. This way with that ST RAM mod, the TOS will get boosted as DTACK is faster on the booster card. Then we can bypass glue like normal. This *should* be doable without too much trouble. As TOS gave around 25% boost last time, then we should see some interesting speed boost figures appearing :) After that I will work on this HC CPU problem again. First step 32mhz CPU based on /AS. That is as far as I got last time. I couldn't get TOS running on 32mhz before, but maybe it will work with faster RAM this time.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby GadgetUK164 » Sat Jan 10, 2015 12:18 am

Very interesting progress! =)

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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Sat Jan 10, 2015 12:57 am

exxos wrote:Some progress at long last. It seems the TOS ROMs are are fault here. I am now booted to desktop like Arne got before the DE mod. So either this mod does not work with lower versions of TOS, or the TOS ROMs have to be fast ones. Though as the GLUE still runs at 8mhz, which controlls the ROMs, I really do not understand why the ROMs need to be faster ?!


No that actually makes sense. :)

GLUE only asserts DTACK (I suspect it may well just be a gated version of AS/UDS/LDS -- that's what Atari used for the ST Book's IDE interface) the problem is the CPU responds to it being asserted by reading the data one clock cycle later (125ns). Now it takes the ROMs a certain amount of time to present data on their outputs, so GLUE will want to interleave that time with the CPU's delay in reading the data (otherwise it'd have to wait for the ROMs to be ready *and* the 125s CPU delay).

The problem you saw is that with the CPU at 16MHz, the CPUs delay is only 62.5ns and so it'll try and read the data before it's properly presented from the ROM. By using faster ROMs, you ensure the data is on the data bus at the right time :)

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Re: 4MB Upgrade & 16MHz Booster progress

Postby Arne » Sat Jan 10, 2015 7:49 am

What TOS did you finally use to make the mod work?
Why do you want to boost CPU beyond 16MHz. Without another RAM boost this is meaningless. Same as 16MHz-only-CPU with stock ST clock-tree beneath.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 10, 2015 9:53 am

SteveBagley wrote:
exxos wrote:Some progress at long last. It seems the TOS ROMs are are fault here. I am now booted to desktop like Arne got before the DE mod. So either this mod does not work with lower versions of TOS, or the TOS ROMs have to be fast ones. Though as the GLUE still runs at 8mhz, which controlls the ROMs, I really do not understand why the ROMs need to be faster ?!


No that actually makes sense. :)

GLUE only asserts DTACK (I suspect it may well just be a gated version of AS/UDS/LDS -- that's what Atari used for the ST Book's IDE interface) the problem is the CPU responds to it being asserted by reading the data one clock cycle later (125ns). Now it takes the ROMs a certain amount of time to present data on their outputs, so GLUE will want to interleave that time with the CPU's delay in reading the data (otherwise it'd have to wait for the ROMs to be ready *and* the 125s CPU delay).

The problem you saw is that with the CPU at 16MHz, the CPUs delay is only 62.5ns and so it'll try and read the data before it's properly presented from the ROM. By using faster ROMs, you ensure the data is on the data bus at the right time :)

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I was thinking GLUE will take a couple of 8mhz cycles before DTACK is issued. As GLUE controls the ROM address bus, I can't really see the ROM running any faster as its all controlled by GLUE, which is still at 8mhz. So the ROM is still at 8mhz. Obviously something else is going on somewhere. Must be some conflict in speed as you suggest.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 10, 2015 10:00 am

Arne wrote:What TOS did you finally use to make the mod work?
Why do you want to boost CPU beyond 16MHz. Without another RAM boost this is meaningless. Same as 16MHz-only-CPU with stock ST clock-tree beneath.


I don't know if it was faster ROMs or TOS, but I only use TOS104 anyway. Though the TOS in before was probably a lower version. But I suspect its the speed of the ROMs.

16mhz CPU only isn't meaningless. It gives around 25% speed boost. I even tried this at 32mhz. Integer division gets 100% speed boost, so 3D games get a huge boost in speed.
This was my 32mhz test. Though when TOS is boosted also, that gives more speed boost.
32m2.jpg
That is still 8mhz RAM.

Also 16mhz CPU and 16mhz TOS gives a good speed boost. Still 8mhz RAM.
16_result.jpg


So once the "RAM bottleneck" is removed. This will result in some interesting speed boost numbers. Idea also being to boost the CPU into 32mhz mode during non-bus access, and TOS access. So defiantly not to be sniffed at.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby joska » Sat Jan 10, 2015 10:44 am

I was thinking GLUE will take a couple of 8mhz cycles before DTACK is issued. As GLUE controls the ROM address bus, I can't really see the ROM running any faster as its all controlled by GLUE, which is still at 8mhz. So the ROM is still at 8mhz.


Your GEMbench results show 200% ROM access. So either GEMbench's ROM speed test is broken, or the ROM is accessed at double speed.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 10, 2015 11:00 am

joska wrote:
I was thinking GLUE will take a couple of 8mhz cycles before DTACK is issued. As GLUE controls the ROM address bus, I can't really see the ROM running any faster as its all controlled by GLUE, which is still at 8mhz. So the ROM is still at 8mhz.


Your GEMbench results show 200% ROM access. So either GEMbench's ROM speed test is broken, or the ROM is accessed at double speed.


ROM instructions will go faster as it uses RAM which is now double speed. Unclear if the ROM chips themselves are running faster as DTACK is still controlled by GLUE at 8mhz. So I suspect when I get my booster board back on, those TOS figures should be faster as DTACK will be based on 16mhz not 8mhz. Will see what happens then. Even if the results are not much higher. Running TOS at 32mhz with the CPU will still give a good boost in speed anyway.

GB will report ROM as 200% as GB is itself is running faster, I mentioned this a few days ago. I suspect ROM is still actually at 100% speed. But as the program is running double speed, its clouding that result. But its clear looking at GB doing the tests, that everything runs much faster. I also found similar when the CPU only runs at 16mhz, ROM gets a 17% speed boost. but ROM itself isn't running faster.

So it depends how you look at it. IMHO ROM is still at 100% speed, but ROM's instructions are running twice as fast because RAM speed is double speed. So in that respect TOS is running at double speed. So GB is right in what it saying. Even though technically the ROMs are still running at stock speed. This is why I want to increase DTACK speed with my booster board, as TOS will genuinely run at 200% speed then. Though GB will probably show something like 250% speed boost for GEM related instructions.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby joska » Sat Jan 10, 2015 2:39 pm

exxos wrote:ROM instructions will go faster as it uses RAM which is now double speed.


Not 100% faster. The actual fetching must be faster too.

exxos wrote:IMHO ROM is still at 100% speed, but ROM's instructions are running twice as fast because RAM speed is double speed.


I would expect any test that tests the ROM speed to measure the time it takes to fetch X words Y times from ROM. True, when the CPU and RAM is twice as fast the ROM speed test will also be faster due to increased instruction execution speed (Unless the CPU speed is a part of the equation, but I don't think GEMbench is that advanced). But it can't be twice as fast unless the actual fetch is twice as fast as well.

So either the ROM is actually accessed twice as fast, or GEMbench does not do what it claims to do.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Sat Jan 10, 2015 2:42 pm

exxos wrote:I was thinking GLUE will take a couple of 8mhz cycles before DTACK is issued.


The CPU already does that though -- it waits for a whole clock cycle from DTACK being low before latching the data from the bus according to the manual and it waits a whole clock cycle from AS going low before it first checks to see if DTACK is low.

As GLUE controls the ROM address bus, I can't really see the ROM running any faster as its all controlled by GLUE, which is still at 8mhz. So the ROM is still at 8mhz. Obviously something else is going on somewhere. Must be some conflict in speed as you suggest.


I've been playing with my new (£10 toy from Amazon) logic analyser on my MEGA and it seems that AS and DTACK are synchronous for GLUE -- see the ROM access section highlighted in white in the image below -- the red sections are RAM accesses, and you can easily see the delay in DTACK on the second highlighted access.

Image

I strongly suspect that GLUE is just using pure combinatorial logic to generate it's DTACK signal, and that the gap between DTACK and AS in the trace is an artefact of the logic analyser sampling rate (it's sampling at 24MHz but also seems to be snapping the signal changes to the 24MHz sample boundaries, look at the 8MHz clock for example), since I've also seen it occur between AS being asserted and DTACK being asserted. (The way to test it would be to remove the 8MHz clock to GLUE and see if the CPU manages to start booting using a logic analyser).

The other possibility is that the combinatorial DTACK signal is fed through a flip-flop clocked at 8MHz but I can't see the point. Certainly, Atari's own design for the IDE interface in the ST Book (attached) just uses combinatorial logic off of the address bus and LDS.

Interestingly, I took a look at Wolfgang Förster's VHDL implementation of GLUE for his SUSKA project and he just uses combinatorial logic as well.

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 10, 2015 3:55 pm

If GLUE is basically following AS for DTACK , or very close to, then this suggests ROM is running at higher speeds already. I was assuming GLUE was a bit more clever in DTACK generation and generating it after 2 8mhz cycles. Though looking at your diagram that does not seem the case. It would also explain why faster ROMs had to be used.

Though that is confusing in itself, as originally we had to generate DTACK in GAL code for it function faster when the CPU was at 16mhz. So both information's are conflicting here.
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Re: 4MB Upgrade & 16MHz Booster progress

Postby SteveBagley » Sat Jan 10, 2015 3:59 pm

exxos wrote:Though that is confusing in itself, as originally we had to generate DTACK in GAL code for it function faster when the CPU was at 16mhz. So both information's are conflicting here.


But wasn't that because your first mod, switched back to 8MHz when AS went low? By generating DTACK in the GAL you kept the CPU at 16MHz when accessing ROM?

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Re: 4MB Upgrade & 16MHz Booster progress

Postby exxos » Sat Jan 10, 2015 4:24 pm

SteveBagley wrote:
exxos wrote:Though that is confusing in itself, as originally we had to generate DTACK in GAL code for it function faster when the CPU was at 16mhz. So both information's are conflicting here.


But wasn't that because your first mod, switched back to 8MHz when AS went low? By generating DTACK in the GAL you kept the CPU at 16MHz when accessing ROM?

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