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was looking at two large ads for them in some further magazines browsing tonight and had to look at a few other web images I could find online a little bit too before asking this...

 

were the carrier cards themselves basically just passive slot adapter or they had some sort of active aspect to them too?

or to put it another way could one had diy their own carrier card pcb and simply plug it in with a suitable zif cpu or would some eeprom/fpga programming work actually be needed in name of being an active carrier card instead by design?

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15 hours ago, chelseayr said:

was looking at two large ads for them in some further magazines browsing tonight and had to look at a few other web images I could find online a little bit too before asking this...

 

were the carrier cards themselves basically just passive slot adapter or they had some sort of active aspect to them too?

or to put it another way could one had diy their own carrier card pcb and simply plug it in with a suitable zif cpu or would some eeprom/fpga programming work actually be needed in name of being an active carrier card instead by design?


I have one somewhere. Do you want better pictures than what you may have found or would a good picture not give you the answer you’re looking for ?

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A normal CPU card, which plugs into a PowerSurge family machine (X500, X600), has:

 

1)  Clock generation and distribution

2)  Voltage supply for the CPU

3)  Bus and Cache multiplier settings

 

A ZIF card relies on the motherboard for all three of these things.

 

So, a ZIF carrier card must supply all of those.    There's no firmware necessary, but you need:

1)  A method to signal the ZIF card's pins what bus speed multiplier and cache multiplier to use.

2)  A method to read the voltage code from the ZIF pins and adjust the the voltage supply appropriately.

3)*  A clock signal (possibly adjustable) and a Clock Buffer chip which divides the clock signal into some number of in phase clock signals for the logic board.

 

I put up a pinout for the X500/X600 CPU slot several years ago.  It should be in teh Wiki.    The number of Clock signals leaving the card is how many you need to split the clock signal into, minus one.   You need one more than the card supplies the logic board, because one of them goes to the ZIF card.

 

Finally, a little know fact about the X500/X600 CPU cards is the "Clock_id" pins.   These three pins tell the motherboard what region the clock is running in.   I assume the Hammerhead chip uses this to adjust bus timings, but I never traced where they go on the logic board.  

 

This can get quite complicated on a clock speed adjustable board.    The "regions" for the Clock_id chips are in 5 MHz groupings.   So, if you do like Newer Tech (or was it XLR8?) did and make your card adjustable in .2 MHz increments, you need logic to adjust the Clock_ID pins every time the clock speed crosses a 5 MHz increment.

 

"Adjust the Clock_ID pins" just means ground them or don't ground them.

 

This Clock_id scheme is why none of the early 3rd party CPU upgrade cards seemed to work above 45MHz.   The upgrade companies didn't know about Clock_id settings and left the pins at some default, which set teh timing on the board for 40 - 45 MHz.  They probably just copied the state of those pins from teh early 120/40 MHz cards or something -- maybe the 180/45.

 

*  Regarding #3 above, I'm not certain that the clock supplied to the CPU has the same phase as the clocks that are sent to the logic board.   There might be a delay line or an inverter in there.   I've never looked -- or if I did, I forgot afterwards.

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interesting, thanks for mentioning everything above trag

 

so I guess it indeed does sound just a little tricky but at least no programming skill needed (well, I guess technically one might still have to write something for the os but thats a different kind of program)

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I think it was the XLR8 card...

 

One of them is adjustable  in .2 MHz increments.  The list of possible speeds they give you in the instructions doesn't actually list all the possible speeds.   Experimenting, I found that eight DIP switches were used to adjust the speed, and they are used in two groups of four.   The first four do a fine adjustment over a range of about 3 MHz.  And the other four do a coarse adjustment of about 3MHz per step over a range of about 45 MHz.

 

I posted the algorithm somewhere in the forums at one point.  Probably in Hacks, but maybe in PCI Macs.

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XLR8 carrier card with a 400mhz G4 interposer module. I pulled the heatsink off for the photo.

The G4 is from a Sawtooth-era G4 Mac. I put this in my PM 8500 circa 2000. I think I had it running at 450mhz iirc.

Simple to use, set the switches to the desired speed and install a small extension to enable.

My 8500 sat  in the closet for about 15 years. A few months back I pulled it out and it wouldn't boot with the carrier card so I reinstalled the original 604 card.

I haven't revisited what might be the issue with the carrier card or system.

Anyway,

 

 

xlr8_carrier_1.jpg

xlr8_carrier_2.jpg

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