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Forum Index : Microcontroller and PC projects : [MM] CGColorMax2/MMBasic 4.4B bricking
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psergiu Regular Member  Joined: 09/02/2013 Location: United StatesPosts: 83 |
Hi, I have left my CGColorMax2 with MMBasic 4.4B running a sprite-intensive program for about 3 weeks non-stop and when i checked on it yesterday it was bricked - all leds off, no VGA output, not detected as a USB device. Tried powering up from either USB or external power - still dead. Fortunately the bootloader still worked, and i was able to re-flash 4.4B on it and everything seems okay now. The program was not doing any I/O, just doing SPRITE COPY and SPRITE MOVE in a loop. It was powered from a 5V 1A "power brick", i did have a couple of very short power brown-outs during this period (Laser printer start-up) but no other device rebooted/complained. Anyone had something similar happening to their 'Mite before ? Any idea why this happened and how it can be prevented ? Thanks. |
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| hitsware Guru  Joined: 23/11/2012 Location: United StatesPosts: 535 |
I'd suspect the "brown-outs" .... |
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| psergiu Regular Member Joined: 09/02/2013 Location: United StatesPosts: 83 |
Can a voltage dip corrupt the PIC32 flash memory ? Bad information above: I am using a 12V 1A power brick, the CGColorMax has a step-down DC-DC converter (8-18V input). Those "brown-outs", caused by the laser printer, are detected only by a APC UPS on the most sensitive setting. Even if the power dipped too much, i don't think the output voltage of the power brick ever went under 8V (min required by CGColorMax's DC-DC converter. Shall i add a big capacitor ( 1000 - 2200 uF ) to the power lines ? |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9066 |
Is the 12v plug-pack you are using, a regulated one, or just a cheapie which may only have an AC-DC rectifier in it and nothing else? You should not have any issues with a regulated plug-pack feeding the CMM2, but I would not really encourage use of a cheap non-regulated plugpack. If you stick your multimeter on the plugpack output, even with no-load, the voltage should be about 12v. If it is about 14-15v no-load, then it is unregulated. The CMM2 has onboard rectification and regulation, so I would imagine that you can feed it with just about anything, but I still prefer feeding things with a regulated plugpack. You could try putting a 1000uF cap across the power input on the CMM2 - it would help if there was a voltage drop or large ripple causing you your problems. Smoke makes things work. When the smoke gets out, it stops! |
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Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
I cannot see how this could happen, although I an not denying that it did. The PIC32 has a brownout protection that would reset the processor in the event of a power dip. To change the flash you have to go through a software unlock routine so the firmware could not have done this accidentally. Perhaps it was a glitch on the power line or a stray cosmic ray particle flipping a memory bit (it can happen). Geoff Graham - http://geoffg.net |
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| hitsware Guru Joined: 23/11/2012 Location: United StatesPosts: 535 |
I'd inspect all my connections and wait and see if it happens again ........... |
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| psergiu Regular Member Joined: 09/02/2013 Location: United StatesPosts: 83 |
Facepalm. 
no load: 18V CGColorMax2 as load: 15V On the cover it says: 12V 1.6A I took a better look at the power brick - it's not a flimsy one but its chunky & heavy. In my book heavier ones were considered better than lighter ones. I opened-it and inside there's a transformer, 4 diodes and a 2200uF cap.  I never even thought that such things are still being made.
I'll replace it with a switching mode one. Moral of the story: Don't be lazy to use that darn multimeter. Thank you very much guys. PS: The "cosmic rays" mentioned by Geoff are not a joke. I happen to take care, during my day job, of lots of servers with lots of ECC RAM. And after every solar storm, you see the Single-Bit memory error counts increasing here and there. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9066 |
If it makes you feel any better, there are still quite a lot of those transformer based plug-packs about the place. The thing is, they are only rated for 12v, at the specified load current. So for example, if yours was rated at 12v 1.6A, then you'd need to be sucking about 1.6A of current for the voltage to be around 12v. Less then that current consumption, and the voltage will be higher(to a point). This is one of the reasons I always use regulated plug-packs, as their output voltage will always be 12v or so, regardless of the current you are sucking out of it. In other words - regulated! 
If the input voltage drops to 15v or so once the CMM2 is connected, that is still within the limits of the input voltage to the CMM2, so I would still have expected it to work OK, but it would be well worth your effort to connect a regulated 12v plug-pack to the CMM2, and see what happens then. Smoke makes things work. When the smoke gets out, it stops! |
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panky Guru Joined: 02/10/2012 Location: AustraliaPosts: 1097 |
Sergiu, I have been running a CGCMM2 as my caravan battery minitor for over 200 days continuous - while not doing any SPRITE work, it does wiggle around the graphics memory fairly severely. It has run 24/7 for this whole period powered straight off the caravan batteries with voltage ranging from 12.1v up to 14.4v with quite a bit of charger "noise" on the line. Like the others, I would suspect either Geoff's random bit flip or perhaps a "dirty" connection somewhere in the power wiring. Cheers, Doug. ... almost all of the Maximites, the MicromMites, the MM Extremes, the ArmMites, the PicoMite and loving it! |
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vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
Then, for continuous work, someone will recommend encasing the Maximite (or any PIC32 micro) in a Pb (lead) case? I also I'm not joking. Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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atmega8 Guru Joined: 19/11/2013 Location: GermanyPosts: 712 |
Read this: Memory errors, cosmic, elektromagnetic fields... |
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