Thank you for all your suggestions.
All mandatory fixes are done as per Exxos' recommendations (except 1771 pull-ups as I have an original FDD).
I will try Frank Lukas' trick to see if it helps.
Cheers.
Mega ST project
- HigashiJun
- Posts: 1212
- Joined: Fri Jun 19, 2020 7:21 am
- Location: Tokyo
Re: Mega ST project
Before trying Frank Lukas' suggested trick, I wanted to check how my setup and the CPU relocator will cope with a low-consumption MC68HC000.
So I have ordered a MC68HC000 on EvilBay and it has just arrived today.
I have fitted it in the relocator and then fitted the relocator itself in my Mega ST.
And the result is: no more RAM errors, freezes nor reboots, even with the blitter on.
So far, so good...
Let's try with the Lightning ST fitted (and fingers crossed):
SUCCESS !
No errors, RAM issues, freezes or reboots any more.
Next step is fitting the STGA and checking the result.
And success again !
Everything works as expected and is rock solid !
These MC68HC000 seem to be a real cure to STs and STEs having some weird issues, and I could only recommend them to all.
OK, now will come the hardest part: trying to make the PAK68/3 work with all this stuff, but it is not for now.
Cheers.
So I have ordered a MC68HC000 on EvilBay and it has just arrived today.
I have fitted it in the relocator and then fitted the relocator itself in my Mega ST.
And the result is: no more RAM errors, freezes nor reboots, even with the blitter on.
So far, so good...
Let's try with the Lightning ST fitted (and fingers crossed):
SUCCESS !
No errors, RAM issues, freezes or reboots any more.
Next step is fitting the STGA and checking the result.
And success again !
Everything works as expected and is rock solid !
These MC68HC000 seem to be a real cure to STs and STEs having some weird issues, and I could only recommend them to all.
OK, now will come the hardest part: trying to make the PAK68/3 work with all this stuff, but it is not for now.
Cheers.
Re: Mega ST project
That is really strange. HC will only generally work when bus resistors are changed and in general make problems worse on machines otherwise.
Could your original CPU be faulty ?
Could your original CPU be faulty ?
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
- HigashiJun
- Posts: 1212
- Joined: Fri Jun 19, 2020 7:21 am
- Location: Tokyo
Re: Mega ST project
As stated before, all except one of your mandatory fixes have been done, so the bus resistors are 2.2K as per your information.
I had two different MC68000 CPUs, and both of them were causing issues with the relocator.
- stephen_usher
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Re: Mega ST project
How many layers is that relocator?
Given my experience, without discrete power and ground planes the 68000 will generate so much noise on the power and ground rails that it will start missing clock cycles at the very least. The HC will be lower power and hence will probably generate smaller power spikes.
Given my experience, without discrete power and ground planes the 68000 will generate so much noise on the power and ground rails that it will start missing clock cycles at the very least. The HC will be lower power and hence will probably generate smaller power spikes.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
Re: Mega ST project
That is not exactly true.. CMOS inputs tend to be more capacitive will actually generate higher spikes, but the overall current would be less than TTL for example. So CMOS tend to oscillate more, and is compounded by bad grounding. Despite its overall current consumption being less than TTL.stephen_usher wrote: ↑Mon Oct 18, 2021 2:18 pm The HC will be lower power and hence will probably generate smaller power spikes.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
- HigashiJun
- Posts: 1212
- Joined: Fri Jun 19, 2020 7:21 am
- Location: Tokyo
Re: Mega ST project
The relocator is 2 layers only.stephen_usher wrote: ↑Mon Oct 18, 2021 2:18 pm How many layers is that relocator?
Given my experience, without discrete power and ground planes the 68000 will generate so much noise on the power and ground rails that it will start missing clock cycles at the very least. The HC will be lower power and hence will probably generate smaller power spikes.
I really do not know why everything is OK now, but the most important is that it do work.
- HigashiJun
- Posts: 1212
- Joined: Fri Jun 19, 2020 7:21 am
- Location: Tokyo
Re: Mega ST project
Had some time today to test my setup further.
I could launch programs from the HDD, FDD and USB without a single issue.
Writing to these devices also worked without a glitch.
So the MC68HC000 definitely cured my MEGA ST issues with the relocator.
(Just to check if I also could make Exxos' 16MHz ST booster rev. 1.4 work, I tried to swap its CPU with the MC68HC000 but it was a no go and I only had a black screen...).
I could launch programs from the HDD, FDD and USB without a single issue.
Writing to these devices also worked without a glitch.
So the MC68HC000 definitely cured my MEGA ST issues with the relocator.
(Just to check if I also could make Exxos' 16MHz ST booster rev. 1.4 work, I tried to swap its CPU with the MC68HC000 but it was a no go and I only had a black screen...).
- HigashiJun
- Posts: 1212
- Joined: Fri Jun 19, 2020 7:21 am
- Location: Tokyo
Re: Mega ST project
Just a new idea for my project.
I had an old slot-in DVD multi drive (Matsushita UJ-875) laying around so I decided to use it in my Mega ST.
When I first installed the drive, I realized it was set as MASTER.
As I also want to use an SSD drive later, which has to be set as MASTER, I had to turn my DVD multi drive into a SLAVE device.
After a little and simple mod, the result is as expected and HDDriver recognizes now the unit as a SLAVE device (though the drive appears with a weird name).
As this is a slim drive, I should be able to pack it somewhere in the Mega ST, even if I have to make a cradle for it.
I had an old slot-in DVD multi drive (Matsushita UJ-875) laying around so I decided to use it in my Mega ST.
When I first installed the drive, I realized it was set as MASTER.
As I also want to use an SSD drive later, which has to be set as MASTER, I had to turn my DVD multi drive into a SLAVE device.
After a little and simple mod, the result is as expected and HDDriver recognizes now the unit as a SLAVE device (though the drive appears with a weird name).
As this is a slim drive, I should be able to pack it somewhere in the Mega ST, even if I have to make a cradle for it.
Re: Mega ST project
Looks like the device name has been byte-swapped?
Really good result that it's recognised & working though!
Really good result that it's recognised & working though!