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Forum Index : Microcontroller and PC projects : MaxiMite initial build discoveries
| Author | Message | ||||
| planet42 Newbie  Joined: 25/08/2011 Location: AustraliaPosts: 5 |
Hi all, finished building the MaxiMite yesterday, so I thought I'd just fire it up straightaway to see how it went. I'm aware there's new firmware but I just wanted to see what the altronics kit default settings were like. Looked good at first, got a steady green led. Then tried an LCD monitor (Dell 2407WP UltraSharp) and got nothing, so I tried a Samsung 172X and got horrible looking scan lines everywhere. (I don't actually have any old CRT monitors anymore - they went to e-waste a long time ago at the wife's insistence :( ). Then tried the composite output, and that worked, so my confidence was restored! I then measured the frequency of the Vertical and Horizontal sync. lines and got 50Hz and 15.62kHz respectively. Now 15.62kHz is pretty close to being exactly half of 31.5kHz, so I guessed that 15.75kHz must be some sort of standard that my LCD monitors couldn't handle. Did a search in google on 'vga 15.75kHz' and got lots of hits and indeed it is some sort of standard, but not one that my LCD monitors can handle. I guessed now that the firmware was the issue, so I then proceeded to update to v2.7, and that fixed the problem. Now have a lovely VGA output that works well on the Samsung monitor. I just wanted to mention this since I couldn't find any reference to this particular point in the forums, and Geoff's SC article does say it should work with LCDs, but it obviously doesn't work on all LCDs at v2.1. Everything else also checked out ok, the keyboard and SD card running autorun.bas all worked perfectly. Now it's time to have fun with this unit! Btw, the composite mentioned earlier was the composite-in of my tv tuner/capture card. Using this it would be possible to record a MaxiMite 'session' as a .mpg file. I'll have a play with this when I get some time. cheers rob [happy little VegeMite on the MaxiMite :)] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ search keywords: vga issue vga problem 50Hz 15.75kHz |
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| aargee Senior Member  Joined: 21/08/2008 Location: AustraliaPosts: 255 |
The frequency you measured, sounds like you've forgotten about the composite jumper select pins, i.e. the firmware is running in composite video mode. Is your Maximite on the original PCB? If so, the jumper is pretty hard to miss. Leaving the jumper in/out and forgetting about it can be a problem if you're using the UBW32 method or one of the breakout boards to build a Maximite. - Rob. For crying out loud, all I wanted to do was flash this blasted LED. |
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Geoffg Guru  Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
I actually have a Dell 2407WP and that is what I tested 2.1 on. So it does work. Geoff Graham - http://geoffg.net |
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