Friday, October 10, 2008

It lives! But its blind

Well, worked out all the problems and have solutions for them all !
nILS sugegsted it was the bridge rectifier that was dropping the extra volt out of my 5v DC. He suggested that I connect the power to J2 rather than J1 as this bypasses the power regulation part of the circuit, which I dont need because Im using the optimized power supply. Does mean that becuase there is no bridge rectifier that you HAVE to get the polarity round the right way though :)

So I did as nILS suggested and I then connected up the core to my Mac using the USB-Midi interface I bought. Had a few problems with working out MIOS Studio, mostly because the the archiver utility thats comes with MacOSX decided that what I wanted it to do when I double clicked the downloaded .ZIP file of MIOS Studio was to unzip the .ZIP file and the unzip the .JAR file it contained, giving me the contents fo the .JAR file in a folder, which I took ages to work out what to do with (which was delete it and use Stuffit to unpack the .ZIP)

So difficulties with over zealous software aside, I managed to get the expeted string upon boot when monitoring the midi ports in MIOS studio, which means its alive!
Uploaded a couple of test apps and they uploaded fine.
Also worked out that I had mis-read the LCD wiring schematic and it was backwards :) De-soldered and re-soldered that and now I haev LCD backlight ! But no characters, even when using the LCD test in MIOS Studio and when using any of the LCD test apps.
As it turns out 2 of the 3 LCDs I bought from CrystalFontz are negative contrast, meaning they need -5v to control contrast. Oh dear.

Fortunatly I have tracked down a schematic to create an inverter that will take between 6 and 12v AC and turn it into 5v+ and 5v-, which is whats needed here. So, another trip to Jaycar required this weekend to build this up, also, I am goign to attempt to add external pots for contrast and brightness control, which will be a nice feature to have.
In the meantime though, I am going to wire up the LCD that isnt negative contrast just to get this going. Its one I plan to use for my green MB_6582, which is the last one I am building so will need it wired up to a plug anyway.

Oh and the rare parts kit for the x0xb0x arrived yesterday.

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