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Forum Index : Microcontroller and PC projects : New version of MMBasic (ver 4.0A)
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Geoffg Guru  Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
I have discovered a small bug in the Colour Maximite. In the design I tried to be smart and use pin 9 of the VGA connector to signal to the firmware that composite video timing should be generated. My VGA documentation showed that pin 9 was unused so I thought that I was safe in using it. However it turns out that others use pin 9 for their own purposes, particularly Hewlett Packard who connect pin 9 to ground on their VGA monitors. This means that when you plug in one of these monitors the Colour Maximite will switch to composite on power up and the monitor will report "signal out of range" or "cable disconnected". The solution is to disable composite video (ie, ignore pin 9) in the new version of MMBasic for the Colour Maximite unless it is specifically enabled by a command. The command is: CONFIG COMPOSITE PAL -or- CONFIG COMPOSITE NTSC Either will enable pin 9 on the VGA connector and set the correct timing. If you have used one of these commands and want to go back to the default situation of ignoring pin 9 you can use the command: CONFIG COMPOSITE DISABLED All these commands only need to be run once as they are saved in flash and will be kept even when the power is off. I have implemented this in a new version of MMBasic (ver 4.0A) which is available for download from http://geoffg.net/maximite.html#Downloads While I was at it I also fixed a similar issue with the DuinoMite where it went into composite mode when a monitor was not plugged in on power up. This also caused a switch to composite mode with the result that the full screen editor (working over USB) would annoyingly only edit lines up to 50 characters long. Similar to the Colour Maximite, composite is now disabled by default and you now need to run one of the CONFIG COMPOSITE commands to enable the automatic switch to composite video. This update also fixes the bug that prevented the display of sprites on the original (monochrome) Maximite - so they now work. You do not need to upgrade if you are unaffected by these issues. The Change Log (included in the update download) details the changes. Geoff Geoff Graham - http://geoffg.net |
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| cosmic frog Senior Member  Joined: 09/02/2012 Location: United KingdomPosts: 284 |
This was happening to me with my HP monitor, all I did was to press the reset button on my UBW32 and then it would work ok. Thanks for the info. |
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
Welcome back! I hope you had a great trip! Micromites and Maximites! - Beginning Maximite |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2914 |
That shows up an oversight on the UBW32-MCC PCB as well, The Schematic I followed for the VGA section was the UBW32 Circuit included in the document `Colour Maximite on the UBW32' which shows this pin 9 as un-connected. I was under the impression that Composite was not supported anymore on the CMM, I was wrong... 
The fix is easy though... If you wish to use pin 9 as a composite/VGA select pin on the UBW32-MCC PCB then you will need to run a jumper from VGA pin 9 to UBW-C14 (about a 1" link). Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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