[Coco] OT: Composite display rolling

[Salvador Garcia]

How about a crude video hack? :-)

http://youtu.be/txGOjIsNgQg

Yes, I can see the correct image on the screen.

Hookup is as follows:

AV out from AVR computer to AV in on LCD screen driver board.

Power IN to AVR computer and daisy chained to LCD driver board

Power iN: 12VDC at 1.4 A

Salvador


 

 

 

-----Original Message-----
From: Zippster <zippster278 at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Mon, Mar 9, 2015 9:08 pm
Subject: Re: [Coco] OT: Composite display rolling


Hi Salvador,

I’m not sure exactly how you hooked up things, or exactly what you
are hooking up, but….

If by rolling composite display you mean you can see an
image of what the screen should be,
but instead of staying centered in the
screen, it is rolling vertically, this would indicate 
the display is not
receiving (or locking onto) the vertical sync.

Maybe some pics of what you are
connecting and the output would help.

- Ed

 
> On Mar 9, 2015, at 8:55 PM,
Salvador Garcia  wrote:
> 
> Hi all,
> 
> Although this is not directly related
to a CoCo issue, information was posted here initially. A few months back (third
quarter 2014) someone placed a post promoting an 8 bit AVR BASIC computer:
> 
>
http://hackaday.io/project/2428-single-chip-avr-basic-computer-v03
> 
> I
thought it would be an interesting project and built it. To make it portable for
demos I looked on eBay and located a small 7" LCD similar to this one:
> 
>
http://www.ebay.com/itm/7inch-LCD-Screen-Display-Monitor-for-Raspberry-Pi-B-B-HDMI-VGA-2AV-Driver-Board-/391022497553
>

> Te major difference is that the one I found last year did not include the
control panel pictured to the right of the main image. The driver board is
basically the same one. The small AVR PC has been connected to two different
composite devices (actually TVs) and works fine. When the LCD arrived I powered
it up and found that the default input was set to HDMI. I figured that it had
auto sensing input, but no. I could not get it to switch to the AV input.
Finally I ordered the control board, but the connectors on the driver and
controller board's cable do not match, so I can't plug in the controller board's
cable to the driver board. I reversed engineered the control board and managed a
hack to switch the driver board's input from HDMI to AV.
> 
> When I connected
the AVR BASIC PC to the AV input I found that the screen rolls fast enough to
make the text on screen illegible. To test I connected the LCD to other AV
sources and the image is fantastic! I don't have the expertise to be able to
debug this and am hoping that perhaps someone here can orient me on what to do
next. Thanks! Salvador
> 

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