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Forum Index : Microcontroller and PC projects : Beta tester anyone? MMBasic V2.3A
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Geoffg Guru  Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
A fix for the video noise issue in V2.3 has been found - this was reported by Glenn in a previous post. This noise, or glitch on the video output, was evident when a BASIC program was running. It did not show up if MMBasic was waiting for user input. The noise was caused by the CPU keeping the memory bus busy which caused the DMA transfer to the SPI peripheral (which in turn generates the video) to start a little late. The solution (which is a bit of a kludge) is to keep the CPU spinning doing nothing until the DMA transfer has started. This has a small performance hit but as we can now use a higher level of compiler optimisation the end result is that programs now run a little faster than in ver 2.3. So, it is a win-win solution. I am looking for some Beta testers to try it out. The update can be download from here: http://geoffg.net/Downloads/Maximite/Maximite_Update_V2.3A.z ip If you find any issues please let me know by posting here or emailing me at projects@geoffg.net If it does cause trouble you can always revert to Ver 2.3 using the bootloader. If no bugs are reported after a few days I will post it on my website for everyone to download. Thanks Geoff Geoff Graham - http://geoffg.net |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
I think thats fixed it Geoff. 
I'll run a few programs and see if it plays up, but it looks like you wont need to buy a VGA monitor after all. I edited you post and turned that url into a clickable link. The forum sofware inserts random spacing into all posts as part of its security, so long links break. The button  turns a url into a working clickable link.
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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BobDevries Senior Member  Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Thanks, Geoff, I've grabbed the V2.3A also, and will flash it tomorrow. Regards, Bob Devries Dalby, QLD, Australia |
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VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hi Geoff, Donwloaded and flashed the maximite with the V2.3A and used a few of the programms from the library and the noise issue may still a problem. Noise is evedent when maximite is waiting for user input when playing the MMFOUR.BAS, however using all the other programmes in the library and a few that I have written myself, this noise issue is not a problem. Hope is helps. Regards, Matthew Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
Hi Matthew Did you try mmfour with 2.2 or 2.3? It was really bad with 2.3. The 2.3A has cleaned it up heaps, maybe a little more noise than 2.2, but vastly better than 2.3. MMFour has lots of vertical lines, easy to spot the interference. I stopped the program (CRTL C) and the interference can still be seen on the vertical lines, so its not the program itself. Either way, 2.3A is a big improvement. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Hi Glenn, I've just re-flashed the Maximite with V2.3 and run the mmfour program and i must say that the noise is not as bad. I'm sorry if this is throwing a spanner in the works, but maybe the way I have the maximite configured or something else is contributing to the noise. I have also re-flashed back to V2.2, run MMFOUR with no noise at all. OK. I've gone back to V2.3A. Try running KEYBOARD.BAS with version 2.3A. Typing in a few characters into the keyboard to see extra lines of text on the screen and it gets worse. Major noise. Regards, Matthew Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
Yeah I see what you mean. Thats actually a different effect to what I was seeing in 2.3. I've uploaded a 1 second video of the effect I was seeing with 2.3, cleared up with 2.3A. 2011-06-08_233817_Maximite23.zip But I can confirm I do see a different effect when running KeyBoard.bas under 2.3A, sort of like a shift to the right by about 50 pixels if a singe random line, if that makes any sense. Only one per video frame. Looks like Geoff will need to buy/borrow/steal that VGA monitor after all. Its only a glitch, nothing to worry about too much and I'm sure Geoff will sort it out. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
Thanks Glenn for the Vid. I'm not to worried about this minor problem, i'm happy with the glitch. As you said, I'm sure given some time Geoff will have a solution. Regards, Matthew Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
When running MMFOUR, I get glitches using V2.3A, but those were there in V2.3 also, and I don't think they're worse. Regards, Bob Devries Dalby, QLD, Australia |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
It seems as if we have two types of glitches or noise. The noise that I fixed was created in the video generation system and resulted in a whole horizontal line of pixels being intermittently shifted 8 pixels to the right. It struck different lines each time and flickered over the screen. The noise shown in Glenn's video is different. It looks like ringing on the video line and seems to shows up only on the trailing edge of a video pulse. I bet that if you wrote a program that generated a single vertical line and used an oscilloscope you would see some ringing (if not then suspect the monitor). I don't know what is causing it (it did not show up on any of the prototypes). It could be caused by the VGA connector, the VGA cable or components like the clamping diode. I hope that this helps. Geoff Geoff Graham - http://geoffg.net |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
OK, did some more tests today. I fixed up my old monochrome crt VGA monitor and plugged it in to the Maximite. To make is easier to explain, I'll call the noise I saw initially and video'd as Effect A, and the timing interference Mathew noticed as Effect B. Tests performed with the old CRT monitor. Flashed the Maximite with Ver 2.3, and didn't see the Effect A I was seeing previously with 2.3 on the LCD monitors ( tried two LCD monitors ), as shown in that video. Loaded the mmfour, and noticed the Effect B Mathew mentioned above. Loaded Keyboard.bas and the Effect B was quite bad. Once the programs are stopped, the image is rock solid. Flashed to 2.3A. Again no Efect A as I was seeing with the LCD monitors, and the Effect B is vastly better, but still there. Most noticable in Keyboard.bas. So from my testing, Effect B, 2.3A is better than 2.3, on my crt monitor. On the LCD monitors I see Effect A on 2.3, and not 2.3A The Maximites screen resolution is not the LCD native resolution, so that may have been causing some of the problems I was seeing. The LCD's processor could be struggling with the Maximites timing signals, and these may have been different in 2.3A, which is why I noticed a differenece. I tried cleaning it up with the controls but didn't help much. The good old analogue crt monitor is rock steady. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
Well, this just demonstrated the benefit of having lots of eyes looking for bugs. Firstly, this is the type B noise that Glenn referred to (a random horizontal line of pixels is intermittently shifted to the right by 8 pixels). Since your reports I have discovered that the 2.3A version fixed just part of the issue. What I did not realise was that a related issue occurred if the Maximite was running a BASIC program while the USB was NOT plugged in. It is difficult to explain the cause but the end result was that this issue also stopped the DMA from starting on time and produces the exact same noise that I had thought I had fixed in V2.3A. I did not spot this new issue because I was testing the Maximite with the USB connected to my laptop (to avoid digging out my keyboard). It was only when I went exploring for the noise that you reported did I uncovered the new cause. So, thank you very much. A new version (2.3B) is available for download from: http://geoffg.net/Downloads/Maximite/Maximite_Update_V2.3B.z ip Could you please give it a run and let me know what you think. Thanks Geoff BTW I bought a cheap monitor in Katherine so I can see exactly what is happening. Geoff Graham - http://geoffg.net |
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| VK6MRG Guru Joined: 08/06/2011 Location: AustraliaPosts: 347 |
OK, looks good. I've run a few programs and no more noise. Good job Geoff, thank you for the quick fix! Regards, Matthew Just so very one knows, i'm running my maximite off usb power.  Its easier to ask forgiveness than to seek permission! ............VK6MRG.............VK3MGR............ |
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donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1310 |
Great, I'll tell my daughter in Darwin (Farrar) to stand down then Geoff. She was asking me when you would arrive. Cheers Don... https://www.32v8.com/1 |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3165 |
Sorry Don, I thought that I had let you know. The monitor was small and cheap ($150) so was too good to pass up. Geoff Geoff Graham - http://geoffg.net |
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jman Guru Joined: 12/06/2011 Location: New ZealandPosts: 711 |
Perfect All the video noise is now gone Thanks for quick update John |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1310 |
No wukkers Geoff. (Technical term my daughter taught me.)
Cheers Don... https://www.32v8.com/1 |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
All good here to Geoff, both CRT and LCD are rock solid. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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