exxos's Atari, Amiga & retro forum

https://exxosforum.co.uk/forum/viewtopi ... =16&t=5536 here exxos described an interesting way to relocate dualtos in C070789 - REV C.
I would like to do such a modification in my PCB C070859 rev.2

Has anyone used such a modification in C070859 rev.2?

I have the same board but an earlier revision. Your link describes cutting a trace on the board and linking two points with a wire, but the description of the "2 CHIP RELOCATION C070789", just below here in The LaST upgrade TOS page page doesn't mention that at all. Instead it mentions soldering a wire to the 74LS11 chip from the CE select pad on the dualtos board. The 74LS11 chip is the U68 one in the lower left corner of your picture, right next to the dual TOS board. Perhaps the forum post is older information and it's not necessary to cut traces?

What I'm wondering is if it's possible to do this relocation mod when using the 2021 16MHz CPU booster as the TOS 2.06 decoder. Since you'd then solder the chip enable wire to the booster, I assume it's not possible? While I'm at it I'm also curious if the resistor fix described here is also necessary with the 2021 booster as decoder. @exxos any thoughts?

krs wrote: 11 Dec 2023 21:37 I have the same board but an earlier revision. Your link describes cutting a trace on the board and linking two points with a wire, but the description of the "2 CHIP RELOCATION C070789", just below here in The LaST upgrade TOS page page doesn't mention that at all. Instead it mentions soldering a wire to the 74LS11 chip from the CE select pad on the dualtos board. The 74LS11 chip is the U68 one in the lower left corner of your picture, right next to the dual TOS board. Perhaps the forum post is older information and it's not necessary to cut traces?

The cut traces method sucked, its why I left it and did it a different / easier way using CE instead.

What I'm wondering is if it's possible to do this relocation mod when using the 2021 16MHz CPU booster as the TOS 2.06 decoder. Since you'd then solder the chip enable wire to the booster, I assume it's not possible?

Don't see why its not possible.

While I'm at it I'm also curious if the resistor fix described here is also necessary with the 2021 booster as decoder. @exxos any thoughts?

Its documented that you need it and mandatory, so you should do as the article says.

exxos wrote: 12 Dec 2023 12:55 The cut traces method sucked, its why I left it and did it a different / easier way using CE instead.

Nice!

Don't see why its not possible.

Ok so I just solder a a wire to both the booster and the 74LS11 chip?

Its documented that you need it and mandatory, so you should do as the article says.

Alright I figured as much. Just wanted to make sure.

Thanks as always. :)

krs wrote: 12 Dec 2023 20:06 Ok so I just solder a a wire to both the booster and the 74LS11 chip?

No, If your using the booster to drive CE then that goes to the DUALTOS board as per the booster instructions.

exxos wrote: 12 Dec 2023 20:12

krs wrote: 12 Dec 2023 20:06 Ok so I just solder a a wire to both the booster and the 74LS11 chip?

No, If your using the booster to drive CE then that goes to the DUALTOS board as per the booster instructions.

Ok yes, so what I was wondering is if it was possible to do the ROM chip relocation mod while using the booster for CE. Does the booster allow me to relocate the ROM chips without relying on the 74LS11? Pardon my ignorance.

krs wrote: 12 Dec 2023 20:33 Ok yes, so what I was wondering is if it was possible to do the ROM chip relocation mod while using the booster for CE. Does the booster allow me to relocate the ROM chips without relying on the 74LS11? Pardon my ignorance.

The ROM chips relocation only changes the CE signal. So driving it from the LS11 or booster shouldn't make any difference. But of course driving from the LS11 means TOS104 decoding only.

exxos wrote: 12 Dec 2023 20:53

krs wrote: 12 Dec 2023 20:33 Ok yes, so what I was wondering is if it was possible to do the ROM chip relocation mod while using the booster for CE. Does the booster allow me to relocate the ROM chips without relying on the 74LS11? Pardon my ignorance.

The ROM chips relocation only changes the CE signal. So driving it from the LS11 or booster shouldn't make any difference. But of course driving from the LS11 means TOS104 decoding only.

Ahh ok now I get it. Alright that's perfect then! :mrgreen:
Thanks for your input once again. Really appreciated.