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Forum Index : Microcontroller and PC projects : CMM2: Overclock to 504MHz?

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matherp
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Posted: 10:00am 27 Jan 2021
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  Quote  will the overclock mode disappear after a firmware update?


Overclock is not an OPTION. It is set by the presence (or absence) of the link between pins 37 and 39 on any given reset or power up.

CPU clock speed has to be set before the firmware is able to read in the options.
Edited 2021-01-27 20:01 by matherp
 
twofingers
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Posted: 11:23am 27 Jan 2021
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  matherp said  Overclock is not an OPTION. It is set by the presence (or absence) of the link between pins 37 and 39 on any given reset or power up.

CPU clock speed has to be set before the firmware is able to read in the options.
Thx Peter!

I think I can insert a TURBO switch (On/Off) between pins 37 and 39.

Best Regards
Michael
 
thwill

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Posted: 11:39am 27 Jan 2021
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Can someone point me to a photo of what the external oscillator mod looks like ? I suspect @WhiteWizzard did mine:

  WhiteWizzard said  ... we have a mod that I will implement for you (makes the vga signal rock solid and eliminates any 'jitter' no matter what screen you use.

but I'd like to be able to confirm.

Thanks,

Tom
Game*Mite, CMM2 Welcome Tape, Creaky old text adventures
 
matherp
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Posted: 11:48am 27 Jan 2021
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Do you have a Waveshare version or the single board? If the latter then it isn't a mod it is standard. If the Waveshare then there should be a rectangular silver device on the motherboard located under the Waveshare PCB
 
thwill

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Posted: 11:51am 27 Jan 2021
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  matherp said  Do you have a Waveshare version or the single board? If the latter then it isn't a mod it is standard. If the Waveshare then there should be a rectangular silver device on the motherboard located under the Waveshare PCB


Waveshare with resistor packs - I know the mod isn't standard, but the quote from @WhiteWizzard suggests to me he probably did it before shipping. I will take a look later, now I know what I am looking for.

Thanks,

Tom
Edited 2021-01-27 21:54 by thwill
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matherp
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Posted: 12:01pm 27 Jan 2021
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thwill

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Posted: 12:26pm 27 Jan 2021
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Thanks for the photo. The oscillator is indeed installed and I've tested over-clocking without any smoke being generated ;-) - just need to add a toggle to my expansion board.

Lovely job Peter,

Tom
Game*Mite, CMM2 Welcome Tape, Creaky old text adventures
 
thwill

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Posted: 12:27pm 27 Jan 2021
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Suggestion: could the firmware indicate that overclocking is ON in its "splash" message ?

Tom
Edited 2021-01-27 22:39 by thwill
Game*Mite, CMM2 Welcome Tape, Creaky old text adventures
 
matherp
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Posted: 02:23pm 27 Jan 2021
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  Quote  Suggestion: could the firmware indicate that overclocking is ON in its "splash" message ?


Done in V5.07.00b9 just posted together with fixes for various bugs Jim found in profiling after AUTOSAVE

http://geoffg.net/Downloads/Maximite/CMM2_Beta.zip
 
twofingers
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Posted: 02:25pm 27 Jan 2021
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During the execution (>30x) of Peter's stress test, the CPUs surface of my overclocked CMM2/504MHz/MMBasic 5.07.00b8 only reached ~46 degrees Celsius (compared to ~38 degrees Celsius for 400MHz). That should be totally okay!

Enclosure open, room temperature 20.3 degrees Celsius.

Stress test: 19946 grains



An observation:
The CMM2 (at 504MHz and 400MHz) freezes when I run my Life program with OPTION RAM.

Michael
 
toml_12953
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Joined: 13/02/2015
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Posted: 03:46pm 27 Jan 2021
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  lizby said  
  twofingers said  Which symbol do you use for this in your country?


Same.

Some of us use U + 2248. It looks like a wavy equal sign.
I can't include the actual character in a message because the forum software won't let me.
 
mclout999
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Posted: 05:24pm 27 Jan 2021
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Look my Mouse adapter has grown a turbo pigtail.

This works very well and It is nice that you can switch speeds on the fly with "CPU RESTART".  I used PIN 34 for my ground because I did not want to undo the heat-shrink on the cable to get to PIN 39. I am running 40 degrees on idol at 480 with "? PIN("TEMP")" and I have a rather hefty aluminum heatsink on it and the case is closed. Is that reasonable or is something wrong? Is it a good idea to maybe put some vent holes above the CPU? Thank you for any input.
 
TassyJim

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Posted: 09:14pm 27 Jan 2021
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  mclout999 said  I am running 40 degrees on idol at 480 with "? PIN("TEMP")" and I have a rather hefty aluminum heatsink on it and the case is closed. Is that reasonable or is something wrong? Is it a good idea to maybe put some vent holes above the CPU? Thank you for any input.

That is on the cold side. My systems run around 50 degrees in normal room temperature.
You have nothing to worry about.
Load doesn't really come into play. its running at full speed all the time. There may be some activity that warms up the video resistors more than others etc but basically, things will not change much.


Jim
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mclout999
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Posted: 04:24am 28 Jan 2021
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  Quote  You have nothing to worry about.
Thanks, Jim.

I mentioned that MauroXavier's masterful demo crashes right after the SD card insertion screen. I was wonder if He might chime in on why he thinks it does. Also can others please verify if it craps out for them and report any other programs that hang with the overclock running? I am going to start running every program I can with it overclocked and report what I find. Thanks.
 
yock1960
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Joined: 18/08/2020
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Posted: 06:25pm 28 Jan 2021
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  mclout999 said  
  Quote  You have nothing to worry about.
Thanks, Jim.

I mentioned that MauroXavier's masterful demo crashes right after the SD card insertion screen. I was wonder if He might chime in on why he thinks it does. Also can others please verify if it craps out for them and report any other programs that hang with the overclock running? I am going to start running every program I can with it overclocked and report what I find. Thanks.


Yesterday, the demo crashed during the spiraling rectangular tunnel effect, today it played all the way through (twice). Temperature after the demo was 46.1, a few minutes later, the temp was 47....must be the breeze from the race car, cooling it down...

Steve
 
George H
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Posted: 02:22am 29 Jan 2021
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Working well for me on a single board CG CMM2, the original one, not the Retromax (yet).  Was a 400mhz version.  Runs Mauro's demo fine.  Shows over 570,000 lines of BASIC per second (!) on the old speedtest program.


-G
 
mclout999
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Posted: 05:20am 29 Jan 2021
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Update mine just crashes on turbo at random so that is not so cool, and it is not the Demo. Oh well, too bad.  I have the 480 micromite.org single board unit.  I put a nice size aluminum heatsink on it with 3M thermal transfer tape. I used an old salvaged PC northbridge heatsink.
Edited 2021-01-29 15:24 by mclout999
 
Nelno

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Joined: 22/01/2021
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Posted: 05:39am 29 Jan 2021
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Worked for me on a Retromax board.

I don't have a lot of software yet to try, so, not sure that's saying much.

It's at least reporting 504 MHz.

The page copy times look marginally faster but nothing to write home about. That's pretty much the extent of what I have handy to test :)
 
RetroJoe

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Joined: 06/08/2020
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Posted: 07:02am 29 Jan 2021
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"Luckily", I had the 400MHz part so the overclocking has been trouble-free so far. I haven't done any timing tests, but everything feels a little "snappier".
Enjoy Every Sandwich / Joe P.
 
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