True 16MHz Mode

[Icky]

But how good does the Frontier demo look? :D

I did run it but did not have time to take a video it was very smooth.

My 16MHz mod is in prototype board hell at the moment. Was trying to make it a lot neater over the weekend but other things got in the way. Will have to get a 16MHz board from exxos' store to truly satisfy my OCD.

If I get my mod sorted out this week I'll do a side by side comparison video of stock STFM, Stock STFM with Blitter against True 16MHz Mode STF remake

[PhilC]

That'll be cool, if / when I finally get the STF working properly I'll do the same with remake vs pak

[exxos]

My remake has been running all day at 16MHz.. Not crashed once. MMU is only a tiny bit warm, nothing basically.

The only issue I found is it doesn't seem to reset when its been turned off overnight.. its probably the crappy 555 reset circuit at fault. Will try and investigate tomorrow, but not a easy thing to solve when it only does it after a long "rest".

[Icky]

My remake has been running all day at 16MHz.. Not crashed once. MMU is only a tiny bit warm, nothing basically.

The only issue I found is it doesn't seem to reset when its been turned off overnight.. its probably the crappy 555 reset circuit at fault. Will try and investigate tomorrow, but not a easy thing to solve when it only does it after a long "rest".

Once I have mine back in 16MHz mode (Vero board hell - don't even go there. Its my kryptonite) I will do similar tests as I have the new reset circuit on my Alpha.

[exxos]

I think I have solved the reset issue... It's where you get a black screen with white border, but pressing reset, or powering off and on again generally makes the machine operate fine afterwards.. ( if you short out the capacitor it will fail to reset every time on power up)

Seems the R919 & 10uF cap is too large. I tried increasing the resistor, increasing the faster, but it just made the problem a lot worse. So I bodged on a 10K ( making R191 about 6K ish) and the reset problem seems to have gone away..

So I think the proper modification should be that R191 to be changed for a 4.7K resistor (was 12K) hopefully this will work for the people as well.

Of course Icky has a new reset circuit ( he should make a few more for us to try ;) )

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[Icky]

Of course Icky has a new reset circuit ( he should make a few more for us to try ;) )

:P - I could do I think I have a few boards and chips lying around. It's an easy circuit to do and makes more space on the board.

I'll see how many I have spare.

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[exxos]

Was running all day yesterday :)

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[exxos]

I just gave this a quick test, and it booted right up first time :) so the fixes I did on the reset circuit seem to have cured this problem of it not starting first time.

Hopefully Icky can send me one of the modified reset circuits To try out at some point ;)

EDIT:

The mod PCBs have been manufactured and they are currently awaiting pickup , then shipment to myself, so hopefully they will not be much longer :)

[exxos]

16MHz mod board + the expansion boards...

There is not much point me adding the 16Mhz boards to my store on their own.. It would just be cheaper for people to get them themselves from OSH..

So I will bundle these three together and add them as a package for my store shortly...

The price will be £15 for the package.. These ended up a lot more expensive than I thought because something messed up during the order and they ended up being shipped into 2 different packages :( The postage and import charges I ended up getting charged twice :(

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EDIT:

Store link.

https://www.exxosforum.co.uk/atari/store2/#0164

These will be sent in a jiffy not signed for to keep the cost down.

[Icky]

Now here is an interesting observation. I have done a comparison of GB6 tests under the 16MHz mode but swapping the MMU from the PLCC to SMT

I ran the tests with each and the numbers are consistent on each run. i.e. the same numbers for each run with the same chip.

The observation is that the GB6 tests with the SMT MMU are slightly faster than the PLCC MMU.

SMT MMU

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PLCC MMU

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