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I did actually start drawing up such a interposer card a couple of years back (or it might have been to replace 7400 series chips with one of the newer ones, I can't remember what mac I was targeting with it) but got board manually drawing the BGA footprint's as I couldn't find them online, I was also a little unsure how well a normal fibreglass PCB would survive being hot air soldered

 

Maybe it's time for a revisit :)

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Just posting  a couple of files.   One is the Motorola/Freescale ZIF datasheet which was linked to earlier.  The link is not working.  The other is an IBM doc on connecting/configuring L2 cache chips -- but it's only for the 750/G3, not for the G4.

 

 

MPCPCMEC.pdf

750_dg.pdf

 

What is the maximum size for the G4 L3 cache?    I ask, because Digikey has some Cypress chips on clearance (no warranty/no returns) which are 250MHz, 512K X 36, $9.10 each.   So a pair of them would yield a 4MB L3.

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On 6/18/2020 at 9:34 AM, max1zzz said:

I did actually start drawing up such a interposer card a couple of years back (or it might have been to replace 7400 series chips with one of the newer ones, I can't remember what mac I was targeting with it) but got board manually drawing the BGA footprint's as I couldn't find them online, I was also a little unsure how well a normal fibreglass PCB would survive being hot air soldered

 

Maybe it's time for a revisit :)

yeah would be interesting to see what can be done :) 

On 6/18/2020 at 1:15 PM, trag said:

Just posting  a couple of files.   One is the Motorola/Freescale ZIF datasheet which was linked to earlier.  The link is not working.  The other is an IBM doc on connecting/configuring L2 cache chips -- but it's only for the 750/G3, not for the G4.

 

 

MPCPCMEC.pdf

750_dg.pdf

 

What is the maximum size for the G4 L3 cache?    I ask, because Digikey has some Cypress chips on clearance (no warranty/no returns) which are 250MHz, 512K X 36, $9.10 each.   So a pair of them would yield a 4MB L3.

ah cool find I had seen the first PDF but not the IBM one :) 

 

maximum size for L3 cache is generally 2MB the 7457 can "do" 4MB but only up to 2MB of it can be used as L3 cache

 

I wonder if the L3 cache setup you mentioned can just be used in 2MB mode with the last 2MB ignored?

(like 512MB SDRAM sticks in a G3 Beige or BW G3)

 

I do still wonder how L2 cache is set/detected by Uninorth based macintoshes, I know there is an SPD chip on the CPU card that contains the info

 

but I dont know what format it is in or how to manipulate it 

 

it must clearly be possible as this guy on ebay upgrade the backside L2 cache on a G4 to 2MB! 

 

https://www.ebay.com/itm/293535144530

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On 6/19/2020 at 12:49 AM, LightBulbFun said:

maximum size for L3 cache is generally 2MB the 7457 can "do" 4MB but only up to 2MB of it can be used as L3 cache

 

Is there any potential use for the other 2MB?

 

On 6/19/2020 at 12:49 AM, LightBulbFun said:

I wonder if the L3 cache setup you mentioned can just be used in 2MB mode with the last 2MB ignored?

 

 

I think there are some 256K X 36 @ 250 chips in the $4 - $6 range, so it would probably make more sense to use those.   I'm not certain, as I browsed scores of SRAM chips and the brain is full.  It all started with a simple search for some Galvantech chips on a Sonnet G3 card, which popped up a link to Digikey where they were clearing them out for $1.7X (don't remember 'x').   128K X 36 @ 250.   And I just kept looking.   It looks like Cypress passed a lot of their old product on to Renessas (sp?) or discontinued a bunch of the old line of SRAM chips recently and there's a bit of a fire sale going on.

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On 6/19/2020 at 12:54 AM, LightBulbFun said:

BTW has anyone contacted sonnet? I hear they are generally quite willing to provide detailed technical info on their old PPC CPU upgrade cards

 

wonder just how much info we could get from them, schematics, board layout info and any technical notes would be neat! LOL

That's a good idea -- for someone else to do.  :-)

 

Didn't you mention that someone else had had success?   Perhaps that person could be contacted.   Presumably, he has established a friendly beach head at Sonnet?

 

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On 10/19/2018 at 3:34 PM, LightBulbFun said:

BTW have you tried contacting sonnet for some details on the CPU card? A friend of mine doing stuff like we do contacted sonnet for info on the TAM G3 upgrade cards and actually got back a good wealth of detail :)

 

Ah, here we go.  Perhaps this friend could be asked?

 

BTW, did you friend get info on how the cache size/speed is encode on the Flash on the board?

 

I ask because i have some G3/512K Cache upgrades and I am sorely tempted to replace the SRAM chips to take them to 1MB, but there's no point if it won't be recognized.

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