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

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matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 8579
Posted: 10:20am 26 Jan 2021
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Please try V5.07.00b8

http://geoffg.net/Downloads/Maximite/CMM2_Beta.zip

In the spirit of hackers everywhere this version has the ability to overclock the CPU to 504MHz for both 400 and 480 MHz models. It may not work for you but it works reliably on the 4 CMM2 I've tested (2 Waveshare and 2 Singleboard)

To enable the overclocked mode put a link between pins 37 and 39 and then power on or reset the processor. You can then remove the link.

Use MM.INFO(CPUSPEED) to confirm the new speed

If it doesn't work simply remove the link and reboot. Use at your own risk!!!!

It is interesting that the 400MHz part has much more headroom for overclocking and this is something ArmmiteH7 users have had available and been doing for some time

504MHz is the highest speed, compatible with creating the USB clock, that I see as reliable on all the processors I've tried so far.
Edited 2021-01-26 20:24 by matherp
 
MauroXavier
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Joined: 06/03/2016
Location: Brazil
Posts: 303
Posted: 11:28am 26 Jan 2021
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Did you notice any temperature increase in the 400 Mhz CPU?

I'm thinking it's a very good idea, but I want to take some precautions, such as placing a heat sink if necessary.

Did you get some random crashes or something like that in some version of the CPU?

I'm sorry to bother you with these questions but is that if the overclock proves to be stable, I can really enjoy the speed gain positively.
 
jirsoft

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Joined: 18/09/2020
Location: Czech Republic
Posts: 532
Posted: 11:44am 26 Jan 2021
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I first thought to overclock my slower CMM2 to 480 MHz to have both with the same speed, but until everybody has the faster (overclocked?) version, is good for me to be able to test my apps also with slower version.
Anyway, it will be nice to have possibility to just overclock to 480 MHz...
Jiri
Napoleon Commander and SimplEd for CMM2 (GitHub),  CMM2.fun
 
Plasmamac

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Joined: 31/01/2019
Location: Germany
Posts: 501
Posted: 11:48am 26 Jan 2021
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Iam seaching for a  Stresstest program
Plasma
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 8579
Posted: 12:47pm 26 Jan 2021
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  Quote  Iam seaching for a  Stresstest program


The CMM2 sits in a tight loop at full speed at all times so there is little you can do to stress it more. Possibly the only thing is to run something with lots of FP

here is what I use to stress everything. You need a suitable picture and some mp3 files on the disk to run it (mp3 decoding use FP)

Mode 1,12 has a memory bandwidth of 115,200,000 bytes per second continuous

Print "MMBASIC benchmark (C) KnivD 2016"
mode 1,12
play mp3 ""
load jpg "tiger-3"
page write 1
List commands
List functions

Dim integer t, i=0
Dim float x(1000), f=0.0
Dim string s=""
Print "Calculating... ";
Do
s=""
f=0.0
i=0
Timer =0
Do While Timer<30000
 i=i+2 : f=f+2.0002
 If (i MOD 2)=0 Then
   i=i*2 : i=i\2
   f=f*2.0002 : f=f/2.0002
 EndIf
 i=i-1
 For t=1 To 100
   f=f-1.0001
   If (f-Int(f))>=0.5 Then
     f=Sin(f*Log(i))
     s=Str$(f,6,6)
   EndIf
   f=(f-Tan(i))*(Rnd(0)/i)
   If Instr(s,Left$(Str$(i),2))>0 Then s=s+"0"
 Next
 x(1+(i MOD 1000))=f
Loop
Print Chr$(13)+"Performance: "+Str$((i*1024)\286,8,0)+" grains"
Loop
End
 
Pilot352
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Joined: 12/08/2020
Location: United States
Posts: 34
Posted: 03:42pm 26 Jan 2021
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If we do this, is there any recommendation on adding additional heat sinks?
 
mclout999
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Joined: 05/07/2020
Location: United States
Posts: 430
Posted: 05:15pm 26 Jan 2021
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Do you have to leave the jumper on or short it every time?  Is there a way to default to that speed?  My mouse cable has is a full 40 pin and I can not have the jumper installed with the mouse plugged in.  I guess I could take it apart and put a momentary switch on those two pins.  Maybe it could eventually be set up with an option command and use the shorted pins to go back to default chip speed. My CMM2 works fine at that speed but MauroXavier's DEMOX crashes and hangs up the machine just after the SD card insert screen.  I know his demo is very reliant on CPU timing so that was my first test. Thanks for a wonderful new feature.
Edited 2021-01-27 03:16 by mclout999
 
twofingers
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Joined: 02/06/2014
Location: Germany
Posts: 1133
Posted: 05:37pm 26 Jan 2021
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  Pilot352 said  If we do this, is there any recommendation on adding additional heat sinks?

I doubt if a heat sink is necessary. During the execution (>30x) of Peter's stress test, the CPU of my CMM2/400MHz/MMBasic 5.06.00 only reached ~40 degrees Celsius.

Edited 2021-01-27 03:40 by twofingers
 
Pilot352
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Joined: 12/08/2020
Location: United States
Posts: 34
Posted: 08:15pm 26 Jan 2021
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-40? Are you sure you don't mean 40? -40 is colder than the arctic. LOL
 
twofingers
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Joined: 02/06/2014
Location: Germany
Posts: 1133
Posted: 08:35pm 26 Jan 2021
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  Pilot352 said  -40? Are you sure you don't mean 40? -40 is colder than the arctic. LOL

Please read it again! "~" (= ASCII 126) is not "-" (= ASCII 45)!
~40 means approximately 40 degrees Celsius.

Which symbol do you use for this in your country?

Michael


  Quote  Usage
Common use

This symbol (in US English) informally[7] means "approximately", "about", or "around", such as "~30 minutes before", meaning "approximately 30 minutes before".[8][9] It can mean "similar to",[10] including "of the same order of magnitude as",[7]  ...
https://en.wikipedia.org/wiki/Tilde

I hope this helps!
Edited 2021-01-27 06:48 by twofingers
 
lizby
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Joined: 17/05/2016
Location: United States
Posts: 3015
Posted: 08:50pm 26 Jan 2021
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  twofingers said  Which symbol do you use for this in your country?


Same.
PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed
 
twofingers
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Joined: 02/06/2014
Location: Germany
Posts: 1133
Posted: 09:02pm 26 Jan 2021
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  lizby said  Same.

Thanks! I wasn't sure.
Michael
 
Pilot352
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Joined: 12/08/2020
Location: United States
Posts: 34
Posted: 09:17pm 26 Jan 2021
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Must be my browser... I don't see a Tilda. I see a minus sign. Odd. Good to know. I wouldn't want my MM2 to freeze. LOL      
 
Pilot352
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Joined: 12/08/2020
Location: United States
Posts: 34
Posted: 09:18pm 26 Jan 2021
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Correction.... I need glasses. LMAO
 
Plasmamac

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Joined: 31/01/2019
Location: Germany
Posts: 501
Posted: 09:32pm 26 Jan 2021
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runs fine here  on 504 000000   thx matherp
Edited 2021-01-27 07:34 by Plasmamac
Plasma
 
MauroXavier
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Joined: 06/03/2016
Location: Brazil
Posts: 303
Posted: 10:23pm 26 Jan 2021
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For me unfortunately did not work as I expected.

I have a 400 Mhz CPU, in my tests, the Wolf3D show corrupted textures after a while and Into The Darkness freeze the system before even loading the stage.

matherp, any chance to change the overclock to 480 Mhz instead 504 Mhz on the 400 Mhz CPUs?
 
matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 8579
Posted: 10:48pm 26 Jan 2021
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  Quote  For me unfortunately did not work as I expected.


You can try this


CMM2V1.5.zip

Have you done the oscillator mod? Probably essential to get the stability
 
MauroXavier
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Joined: 06/03/2016
Location: Brazil
Posts: 303
Posted: 03:54am 27 Jan 2021
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  matherp said  Have you done the oscillator mod? Probably essential to get the stability


The difference in speed of 400 Mhz to overclocked 480Mhz in the Into the Darkness is very noticeable, but it freezes the system running only about 30 seconds... But as I do not have the oscillator mod, probably this is the cause of the instability.

Anyway, thanks for your support.
Edited 2021-01-27 13:55 by MauroXavier
 
LeoNicolas

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Joined: 07/10/2020
Location: Canada
Posts: 444
Posted: 07:45am 27 Jan 2021
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Tomorrow I will try it in my CMM2 waveshare with the oscillator mod.
I will post the results soon.
 
twofingers
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Joined: 02/06/2014
Location: Germany
Posts: 1133
Posted: 09:46am 27 Jan 2021
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Hi Peter,
will the overclock mode disappear after a firmware update?

Regards
Michael
 
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