exxos's Atari, Amiga & retro forum

I have been following the discussions about the bad DMA for the last few years but didn't have the ability to buy an UltraSatan until recently. Before doing so I upgraded the CPU to an HC version from exxos store and measured the capacitors in the PSU. They are not that bad but it will be my next project to recap it. Anyways, the HC was installed, the Ultra Satan came and..... (drums) things at first seemed to work until I was trying to save desktop in GEM. Desktop.inf on the card was 0 bytes. Of course, I was trying with what is generally known NOT to be friendly SD, a Class 10 Transcend card. Thank god that together with the US came a SanDisk Class 4. Tried that, worked fine (ordered a second one to have). Checked reads/writes, everything seems FINE. So, no bad DMA, only bad SD cards....

To cut a long story long, avoid cards that may not work. When you read that some SD cards work perfectly with US, do not experiment with others.

Also, another proof that DMA story is just something that needs to be tackled with a bit of logic and not hot temper. Buy a HC CPU, recap your PSU. You can see rev of my board and DMA here. BTW, I do not have any side effects with graphics in demos except a minor in WeWere but frankly, I don't care.

My next projects:

a) recap PSU
b) do the STE ghosting fix (was obvious in Bad Apple demo)
c) Maybe upgrade the TOS? I am on 1.06. Would I get anything overall going to 2.06? STability vs Compatibility?

There does seem to be a lot of stories of late of bad SD cards and fakes. Though seems to be a lot worse lately. Odd that swapping the card solved the problem. Didn't know US had issues with some SD cards.

The problem you describe is generally the classic "DMA bug" symptom when you do not have a HC CPU, but this is not a cure all fix. Different brands of ROM can make or break DMA system. Generally if you still have problems you need to change the bus pullups and these additional problems generally go away. Would be interesting if you ever do that fix, to try the malfunctioning SD card again.

If you want to retain compatibility as much as possible you could get a dual TOS board and run 1.62/2.06 in your STE.

1.06 does have some bugs, so you probably want to move away from it to at least 1.62. 2.06 offers a lot of UI upgrades and it's my preferred TOS for STE. A lot of stuff is patched these days and works fine on 2.06 anyway.

Nice to hear somebody reporting the SD card problems, this isn't always reported. My personal favourite SD cards are SanDisk SDHC 8GB cards, the blue ones.

They work in my CosmosEx, UltraSatan and also my SIDE3 cart for my 8 bit Ataris. They are inexpensive, have more than enough capacity and reliable.

Thanks for your replies guys.

One thing to test whether I run into a bad card is to use another Class 10 SD card and see how it performs. I have run into a few discussions about cards not working properly with US, even in discussions about CF cards on the Amiga, mostly with Transcend cards. Strange thing is that both SDs that work are Sandisk, the one bought here is Made in Malaysia, the one that came with US is Made in China both the blue ones. The Transcend is a 4GB card (brand new), the others are 32GB. I will do the PSU recap soon and I will test again before doing anything more. But to be honest, if the card does not "break" at some point, I may not do anything more like the bus pullups. If I have issues, then yes, that will be done as well.

About the TOS, I have to look at the jumpers because the last photo I got is not so clear. Look like they are exactly like in the photo with the 2.06 roms here

https://www.exxosforum.co.uk/atari/last/ ... htm#STE206

Remember the jumpers are specific to ROM types and not TOS versions, so you may need to change them.

Have a look here: https://temlib.org/AtariForumWiki/index ... OS_Upgrade

The 'resistors' are no more than a zero ohm link, so on my STEs I simply installed standard jumpers instead for easy changes at a later date.

Yes. I speak about TOS ROMS from exxos store. I can see from this image that the resistors/jumpers on that photo are the same as the photo I attached from my STE.

I use the ones on the Lotharek site, sourced from a different place:

https://lotharek.pl/products.php?id=23

Even found one in Tesco when up in Scotland.

An update about using a new class 10 card. I bought a micro SDHC card, 32GB with SD adapter. It is a Sandisk, serial SDSQUNS-032G-GN6TA. The one I used and worked is a class 4, 32GB Sandisk SD. The new card also worked fine. Checked with AHPT, class 4 gives 1092KB/s, class 10 gives 1099KB/s. Now I am on dilemma which one to use! :mrgreen: . Access time is also the same, around 7.6ms. I don't seem to have the DMA issue really, the other was just a crappy card. I did read and writes, everything seems fine.