0xCats wrote on 2022-04-02, 11:22:To add something more […]
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To add something more
A dual PCB design with headers between them is almost entirely unworkable. Here is why:
I ran a simulation of it and tried with just normal stacked sockets to find out how badly it affects system stability and reliability. How many sockets can I stack with the CPU still working.
It's safe to say from testing that even 2x1 sockets stacked is a problem if they are not completely tightly wedged into each other. The Kingston turbochip module actually soldered the two stacked sockets to resolve this.
Even just 2x2 stacked leads to glitches and a lot of EMI, crosstalk and other capacitive coupling problems.
But at 3x2 stacked sockets as seen above in my pictures it is a total mess at the 66Mhz FSB.
And this was with tightly stacked sockets, with 2.54mm pin headers plus PCB trace routing I expect it to be much worse.
It works on a 486 and such due to their low FSB and much lower signalling requirements.
But for Pentium, especially for the Host data bus and cache controls it needs to done right or just becomes real glitchy mess.
As for the socket spacing, this is something that's relatively easy to solve with modern IC's, all of the voltage regulation stage can fit inside the socket and over the unused socket lever/cover area.
With modern electronics this can be even smaller than the original Kingston TurboChip module:
IMG20220111151235.jpg
IMG20220111151241.jpg
excellent!
question, how do we solder the two sockets together?
for my design I want to put the tweaks from my other project on it also so I want to find room for that. But something I absolutely hate about the old adapters is the switches being under the cpu that was so hard to pop out each time you wanted to change a setting.
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So far, my "desired" features list is this,
(Though some of these may never happen as many of them are of course asking a lot but I'll list them):
-A top of the line voltage supply for vcc2 that is more stable than can be found on any socket 7 motherboard from the factory. With a settable range between 1.4v-3.5v
- wt/wb pull up and pull down switches
-bf0, BF1, BF2, Tillamook BF2 pull up and pull down switches
-Tillamook cache mods with switchs
-Tillamook vccdet mod with switch
-Temp probe
-Temp/voltage display or at least a external sensor header for external reading. There are some very small devices these days with little oled displays like gotek and atx2at something like that may fit here? but is asking a lot. though may be possible..
-One of the old interposers had a feature where it would drop the multiplier based on temperature. (will cpus even respond to multiplier change in real time?)
-Cache would be cool, but I need to learn a lot before I'm there.
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micro or regular jumpers may be the answer to space constraints they could be along the edge of the socket flushagainst the socket down both sides using minimal space