[Coco] OT: Composite display rolling

[Salvador Garcia]

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