Page 1 of 1

520STFM - TOS upgrade confusion

Posted: Sat Jul 13, 2019 1:39 pm
by dhoggan
Hi,

I'm hoping someone can help me understand how (or if) I can upgrade my 520 STFM with TOS 1.02 and 512K RAM. The more I read on the subject, the more I seem to get confused with the various options.

The board is a C070789-001 Rev.B with six 28-pin ROM sockets on the left-hand side. TOS 1.02 only occupies two of these - U48 and U53. The 512K memory appears as two banks of eight ICs with a space and solder pads for a further two banks of eight ICs.

I would like to be able to use an UltraSatan with this, but have been told that I should consider upgrading TOS and memory.

My first confusion is what can be done about upgrading TOS. If I read it correctly, the highest TOS version that I can realistically use is TOS 1.04? I was hoping that it would be simple case of swapping the two TOS 1.02 chips with two 1.04 chips but I'm not so sure now. I've see some options for 1.04 on two 32 pin chips, on two 28 pin chips (but out-of-stock) and on 6 chips (in stock). Can I replace my current two chips with TOS 1.04 on six chips? Or, do I need to hope that the two -chip version comes back into stock?

As for memory upgrade, I think my options are easier - I simply buy the STFM DRAM 512K kits and axial RAM capacitor pack and then get busy soldering it in?

Sorry my first post is a 'please help' one, but I've been reading up as much as I can and now have confused myself totally!

Thanks,

Dave

Re: 520STFM - TOS upgrade confusion

Posted: Sat Jul 13, 2019 2:35 pm
by exxos
2 chip 28pin 104 is basically gold dust. Some sellers sell eproms which can be hacked in, that's where the 28 vs 32 pin chip issue comes in. but they are not a simple swap.

You can "downgrade" from using 2 chip to 6 chips from my web store. There are jumpers on the motherboard to do it. Or you can use a dualtos board which replaces the 2chips with a PCB and plcc ROM which holds 102 and 104.

As for ram, with hard drive adding 512k to bring you to 1mb isn't going to be enough. You really need 4mb if you want to run games from hard drive as the driver software takes up ram as well. If you stick with 1mb then your only going to be able to play 512k games not the 1mb ones.

Re: 520STFM - TOS upgrade confusion

Posted: Sat Jul 13, 2019 9:25 pm
by tzok
You may look for 27C1000 (NOT 010 nor 1001) EEPROMs, but they are likely to be 200ns ones, so on the very border line of the acceptable latency for a stock 8MHz ST. They are 32 pins, but the "excessive" pins can be tied together and hooked to VCC (except \OE which should be tied to GND). You may also cross-wire a regular JEDEC compatible 1Mbit EEPROM (27C010) or even a Flash. It should be 150ns or faster EEPROM or Flash.

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 10:04 am
by rubber_jonnie
In answer to your question about TOS 1.04, that is the latest version you can run on your machine without installing a booster. A booster will allow the use of TOS 2.06.

The advantage of 2.06 is that you can boot from hard disk having installed drivers, whereas with 1.04 you need to boot from a floppy containing the hard disk drivers.

If you just want to upgrade the ROM, then I'd recommend this: https://www.exxoshost.co.uk/atari/last/storenew/#0131

Its the easiest way to upgrade in your situation, and allows for use of TOS 1.02 as well, and is pretty easy to install.

For RAM expansion you have this: https://www.exxoshost.co.uk/atari/last/storenew/#0020 or this: https://www.exxoshost.co.uk/atari/last/storenew/#0035

If you aren't happy soldering then the second version is best, although if your Shifter is soldered in, you will still need to remove it and install a socket.

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 11:03 am
by czietz
rubber_jonnie wrote:
Sun Jul 14, 2019 10:04 am
The advantage of 2.06 is that you can boot from hard disk having installed drivers, whereas with 1.04 you need to boot from a floppy containing the hard disk drivers.
Actually, that's not true. TOS 1.04 (even TOS 1.00) can boot from an ACSI hard disk just fine. No floppy disk required. (TOS 2.06 adds that capability for IDE drives, as well.)

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 11:11 am
by dhoggan
Hi everyone,

Thanks for all the information - and for sorting out the confusing mess I had gotten myself into with all the options. I think the 'killer' for me was the fact that, even if I were to get TOS 1.04 and the system up to 1MB, I might still need more memory for use the UltraSatan to its full potential - at least with games. And, given the cost of the upgrades, it might be cheaper to buy an STE off eBay.

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 11:32 am
by exxos
dhoggan wrote:
Sun Jul 14, 2019 11:11 am
Thanks for all the information - and for sorting out the confusing mess I had gotten myself into with all the options. I think the 'killer' for me was the fact that, even if I were to get TOS 1.04 and the system up to 1MB, I might still need more memory for use the UltraSatan to its full potential - at least with games. And, given the cost of the upgrades, it might be cheaper to buy an STE off eBay.
A STE is a good machine also and of course easy to upgrade RAM. Though you also have to factor in that STE's generally have TOS106-206 installed which causes compatibility problems with some games. Also STE's tend to have issues with ultrasatan (and other hard drives) so will need some fixes doing "out of the box" before anything else.

It can actually get a pretty complex topic.. But if games is the main thing you want to do, then IMHO your better sticking with a STFM. You can use floppy or gotec drives instead of a hard drive, in that case 1MB should be fine.

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 1:23 pm
by dhoggan
Ah, nothing's every easy I guess :D

My main reason for considering the UltraSatan is for multi-disk games and the annoyance of swapping them, as well as the increased risk of damage to the floppies themselves. I have seen lots of people talk about the Gotek, but thought it was a pure floppy replacement so I'd still need to 'change' disks, even if through pushing buttons. I'll do some more research.

But that said, I do fancy the challenge of upgrading the STFM so I'll not discount it just yet!

Thanks,

Dave

Re: 520STFM - TOS upgrade confusion

Posted: Sun Jul 14, 2019 2:14 pm
by rubber_jonnie
czietz wrote:
Sun Jul 14, 2019 11:03 am
rubber_jonnie wrote:
Sun Jul 14, 2019 10:04 am
The advantage of 2.06 is that you can boot from hard disk having installed drivers, whereas with 1.04 you need to boot from a floppy containing the hard disk drivers.
Actually, that's not true. TOS 1.04 (even TOS 1.00) can boot from an ACSI hard disk just fine. No floppy disk required. (TOS 2.06 adds that capability for IDE drives, as well.)
Ahh yes, I stand corrected, ACSI yes you're right, I've been working on the IDE interface of late and got my wires crossed!