Quote:
Originally Posted by Rochabian
I'm curious...
Do you have tried 120Mhz with the older 68030@40Mhz too ?
Perhaps the MMU on the full 68030@50 doesn't like the overclock.
BTW it was a nice try, and you've reached the 10M barrier, well done !
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That thought crossed my mind after I had put it back 108mhz but from conversation with Stephen Leary I'm fairly certain it won't work at 120mhz. I don't think the issue was the processor but rather the code written by Stephen in that TF330 that doesn't like the clock speed and that is by no means a criticism of his excellent work.
My reason for this conclusion is that the machine posted to the CD32 screen at 120mhz so all rom tests must have passed fine. Its the IDE that doesn't like the speed. All clocks on the card are derived from the 1 crystal so you're not just overclocking the CPU but the RAM and the IDE. The CPU can take it fine, the RAM also is fine (its modern memory after all) but IDE I imagine is a lot more fussy about the speed it will work at.
I am a little reluctant to try it again to be honest. The crystal has been off and on maybe 5/6 times now and I don't want to risk lifting pads by overheating. Just with the work I've done so far there is already a little damage to the solder mask and you can appreciate I don't want to risk bricking the board. I'm not an expert with SMD work but getting better.
If you can find a 110mhz crystal I think that may work but they seem like hens teeth for whatever reason. 108 and 120 are the only speeds above 100 that I could easily find and even at that they had to come from China.
To be honest I'm more than happy with 10.5Mips in sysinfo. I believe I've proved a small overclock is indeed possible and everything seems stable at 108mhz.
I ran memory tests for a good hour the other night and it didn't miss a beat, well once I got the test working that is. It seems there is something weird going on in my startup sequence causing the test to fail from within workbench. Its perfect if I boot with no start-up sequence though. I think the crash is because of the MMU library that I've installed. Using the MMU tools I've mapped the ROM to fast ram which is then write protected causing the test to crash. I could be wrong but thats my best guess.