A1200 motherboard FPU

[delshay]

the FPU on the A1200 motherboard works but there may be a problem with expansion cards. more test is needed.

anyone willing to try this modifcation will be at their own risk.

[djbase]

I did that already years ago but makes no sense at all. Just a proof of concept.

[delshay]

 :-)

DJBase wrote:
I did that already years ago but makes no sense at all. Just a proof of concept.

what did you do to fix the problem when accelerator cards are fitted with their own on-board FPU.

[djbase]

delshay wrote:
what did you do to fix the problem when accelerator cards are fitted with their own on-board FPU.

Removed the FPU from board.

[mongo]

It is actually possible to use more than one FPU with a 68020 or 68030, but no existing Amiga software would make use of more than one.

[delshay]

DJBase wrote:

delshay wrote:
what did you do to fix the problem when accelerator cards are fitted with their own on-board FPU.

Removed the FPU from board.

i think iv found a way where i don`t have to remove it.

i will test when i have more time.


                  --------------------
its also possible that some accelerator cards were made with the A1200 motherboard FPU not in mind as no A1200 were shipped with FPU,this will have to be checked.

[delshay]

i dont know how important this information is but i post it anyway.

iv now found a way around the problem for my blizzard ppc card. the blizzard ppc card now has control of th onboard A1200 motherboard FPU and works as follows.

when the blizzard ppc card is disabled by holding down the 2 key the system will halt. after a second soft reset the system will boot with the 020/FPU working. i dont think there's a way around this but will look into this when i have more time as i think the reason it halt's maybe down to the switch over when the blizzard ppc card is still active at start-up when holding down the 2 key untill it get's disabled.

if the 68ec020/688882 is active and a switch over is done to reactivate the blizzard ppc card by doing a 20 sec soft reset it does not halt.


IMPORTANT UPDATE: Blizzard PPC card will need a small modification in-order for the above to work.

**** ALL MODIFCATION AT YOUR OWN RISK ***

[pyrre]

Interesting project....

Is it possible to swap the cpu as well?
or overclock it to a more reasonable speed...?

[delshay]

Interesting project....

Is it possible to swap the cpu as well?

or overclock it to a more reasonable speed...?

Is it possible to swap the cpu as well? yes
 
i can change any type of chip no matter what type or shape including Blizzard PPC 603e,changed to whatever i want,at the moment im trying to get a PPC 745 or a 740L to work so im very busy.

as for upgrade for other users i have 3x real 603e 250Mhz,one im using at the moment but im almost sure i will not be using it in any of my project`s.
i may also do one or two 300Mhz but this depends on what happens in the next few weeks this will be a first come first served via PM when i think the time is right.


or overclock it to a more reasonable speed...?

never tryed to overclock the 603e 250Mhz but im sure it will do some overclocking
as for the 300Mhz version iv only overclocked it to 320Mhz with a 80Mhz osc without a single problem but im sure it will go higer.

also at some point a Cyberstorm PPC will be fitted with a 375Mhz 604e and will attemped to overclocked it to 400Mhz