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classic_ii_fpu
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Add pictures to README.md.

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Marcin Dymczyk 2021-01-27 22:42:27 +01:00 committed by GitHub
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README.md
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@ -4,12 +4,15 @@ This repo contains a KiCAD design of an expansion card that adds an MC68882 FPU
### Results
The board dramatically improves the Floating Point performance of the computer.
After plugging in the card, it should be immediately visible in some tools (here System Information of MacBench):
![FPU card present in System Information](img/classic_ii_system_info.png)
MacBench 1.0 results running @16 MHz (system clock):
The board dramatically improves the Floating Point performance of the computer. MacBench 1.0 with an FPU@16 MHz (system clock) reports over a 13x improvement.
When using an external 40 MHz oscillator, the Floating Point result goes up even a bit more - to 15.7x (it's not proportional to the clock frequency as at some point the slow 16-bit bus becomes a limiting factor):
![FPU benchmark showing Floating Point improvements](img/classic_ii_benchmark.png)
When using an external 40 MHz oscillator, the Floating Point results improves a bit more (it's not proportional to the clock frequency as at some point the slow 16-bit bus becomes a limiting factor):
(look at the Floating Point row)
### Order a PCB
@ -32,6 +35,14 @@ If you want to order a PCB directly, I have created a model on PCBWay:
(sorry, I had most components at hand, so I only have Digikey references for the rather specific ones)
### Pictures
![FPU top](img/IMG_3241.jpg)
![FPU bottom](img/IMG_3249.jpg)
![FPU installed](img/IMG_3247.jpg)
### References
The MC68000 KiCAD library from https://dev.sigpipe.me/DashieElectronics/Jackalope